global: snapshot

Cargo.lock

@@ -568,6 +568,7 @@ version = "0.1.0-alpha.0"
 dependencies = [
  "brk_query",
  "brk_types",
+ "oas3",
  "schemars",
  "serde_json",
  "vecdb",
@@ -1203,6 +1204,7 @@ version = "0.1.0-alpha.0"
 dependencies = [
  "aide",
  "axum",
+ "brk_binder",
  "brk_computer",
  "brk_error",
  "brk_fetcher",
@@ -1364,9 +1366,9 @@ dependencies = [
 
 [[package]]
 name = "cc"
-version = "1.2.49"
+version = "1.2.50"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "90583009037521a116abf44494efecd645ba48b6622457080f080b85544e2215"
+checksum = "9f50d563227a1c37cc0a263f64eca3334388c01c5e4c4861a9def205c614383c"
 dependencies = [
  "find-msvc-tools",
  "jobserver",
@@ -3219,6 +3221,23 @@ dependencies = [
  "syn 2.0.111",
 ]
 
+[[package]]
+name = "oas3"
+version = "0.20.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "16f67c885c7b19aaf652e84102035258ecb4e0425a4f71037e187798e367bd87"
+dependencies = [
+ "derive_more",
+ "http",
+ "log",
+ "once_cell",
+ "regex",
+ "semver",
+ "serde",
+ "serde_json",
+ "url",
+]
+
 [[package]]
 name = "objc2"
 version = "0.6.3"
@@ -4198,7 +4217,7 @@ dependencies = [
 
 [[package]]
 name = "rawdb"
-version = "0.4.3"
+version = "0.4.4"
 dependencies = [
  "libc",
  "log",
@@ -5388,7 +5407,7 @@ checksum = "8f54a172d0620933a27a4360d3db3e2ae0dd6cceae9730751a036bbf182c4b23"
 
 [[package]]
 name = "vecdb"
-version = "0.4.3"
+version = "0.4.4"
 dependencies = [
  "ctrlc",
  "log",
@@ -5407,7 +5426,7 @@ dependencies = [
 
 [[package]]
 name = "vecdb_derive"
-version = "0.4.3"
+version = "0.4.4"
 dependencies = [
  "quote",
  "syn 2.0.111",

crates/brk_binder/.gitignore

@@ -0,0 +1 @@
+clients/

crates/brk_binder/Cargo.toml

@@ -11,6 +11,7 @@ build = "build.rs"
 [dependencies]
 brk_query = { workspace = true }
 brk_types = { workspace = true }
+oas3 = "0.20"
 schemars = { workspace = true }
 serde_json = { workspace = true }
 vecdb = { workspace = true }

crates/brk_binder/DESIGN.md

@@ -8,27 +8,29 @@ Generate typed API clients for **Rust, JavaScript, and Python** with:
 
 ## Current State
 
-### What Exists
+### What's Working ✅
 
-1. **`js.rs`**: Generates compressed metric catalogs for JS (constants only, no HTTP client)
+1. **JS + JSDoc generator**: Generates `client.js` with full JSDoc type annotations
-2. **`tree.rs`**: (kept for reference, not compiled) Brainstorming output for pattern extraction
+2. **Python generator**: Generates `client.py` with type hints and httpx
-3. **`generator/`**: Module structure for client generation
+3. **Rust generator**: Generates `client.rs` with strong typing and reqwest
-   - `types.rs`: Intermediate representation (`ClientMetadata`, `MetricInfo`, `IndexPattern`, `schema_to_jsdoc`)
+4. **schemars integration**: JSON schemas embedded in `MetricLeafWithSchema` for type info
-   - `rust.rs`: Rust client generation (stub)
+5. **Tree navigation**: `client.tree.blocks.difficulty.fetch()` pattern
-   - `javascript.rs`: JavaScript + JSDoc client generation ✅ IMPLEMENTED
+6. **OpenAPI integration**: All GET endpoints generate typed methods
-   - `python.rs`: Python client generation (stub)
+7. **Server integration**: brk_server calls brk_binder on startup (when clients/ dir exists)
 
-### What's Working
+### Generated Output
 
-- **JS + JSDoc generator**: Generates `client.js` with full JSDoc type annotations
+When `crates/brk_binder/clients/` directory exists, running the server generates:
-- **schemars integration**: JSON schemas embedded in `MetricLeafWithSchema` for type info
-- **Tree navigation**: `client.tree.blocks.difficulty.fetch()` pattern
 
-### What's Missing
+```
-
+crates/brk_binder/clients/
-- OpenAPI integration for non-metric endpoints
+├── javascript/
-- Python client implementation
+│   └── client.js      # JS + JSDoc with tree + API methods
-- Rust client implementation
+├── python/
+│   └── client.py      # Python with type hints + httpx
+└── rust/
+    └── client.rs      # Rust with reqwest + strong typing
+```
 
 ## Target Architecture
 
@@ -56,13 +58,13 @@ const data = await client.tree.supply.active.by_date.fetch();
 ```python
 # Python
 client = BrkClient("http://localhost:3000")
-data = await client.tree.supply.active.by_date.fetch()
+data = client.tree.supply.active.by_date.fetch()
 ```
 
 ```rust
 // Rust
-let client = BrkClient::new("http://localhost:3000");
+let client = BrkClient::new("http://localhost:3000")?;
-let data = client.tree.supply.active.by_date.fetch().await?;
+let data = client.tree().supply.active.by_date.fetch()?;
 ```
 
 ## Implementation Details
@@ -78,19 +80,11 @@ Each tree leaf becomes a "smart node" holding a client reference:
  * @template T
  */
 class MetricNode {
-  /**
-   * @param {BrkClientBase} client
-   * @param {string} path
-   */
   constructor(client, path) {
     this._client = client;
     this._path = path;
   }
 
-  /**
-   * Fetch the metric value
-   * @returns {Promise<T>}
-   */
   async fetch() {
     return this._client.get(this._path);
   }
@@ -100,30 +94,30 @@ class MetricNode {
 ```python
 # Python
 class MetricNode(Generic[T]):
-    def __init__(self, client: BrkClient, path: str):
+    def __init__(self, client: BrkClientBase, path: str):
         self._client = client
         self._path = path
 
-    async def fetch(self) -> T:
+    def fetch(self) -> T:
-        return await self._client.get(self._path)
+        return self._client.get(self._path)
 ```
 
 ```rust
 // Rust
-pub struct MetricNode<T> {
+pub struct MetricNode<'a, T> {
-    client: Arc<BrkClient>,
+    client: &'a BrkClientBase,
     path: &'static str,
-    _phantom: PhantomData<T>,
+    _marker: PhantomData<T>,
 }
 
-impl<T: DeserializeOwned> MetricNode<T> {
+impl<'a, T: DeserializeOwned> MetricNode<'a, T> {
-    pub async fn fetch(&self) -> Result<T, BrkError> {
+    pub fn fetch(&self) -> Result<T> {
-        self.client.get(&self.path).await
+        self.client.get(self.path)
     }
 }
 ```
 
-### Pattern Reuse (from tree.rs)
+### Pattern Reuse
 
 To avoid 20k+ individual types, reuse structural patterns:
 
@@ -142,17 +136,6 @@ struct Supply {
 }
 ```
 
-### Rust Client: Using brk_types
-
-The Rust client should import `brk_types` rather than generating duplicate types:
-
-```rust
-use brk_types::{Height, Sats, DateIndex, ...};
-
-// Response types come from brk_types
-pub struct MetricNode<T: brk_types::Metric> { ... }
-```
-
 ## Type Discovery Solution ✅ IMPLEMENTED
 
 ### The Problem
@@ -163,45 +146,9 @@ Type information was erased at runtime because metrics are stored as `&dyn AnyEx
 
 Use `std::any::type_name::<T>()` with caching to extract short type names.
 
-> **Note**: Unlike `PrintableIndex` which needs `to_possible_strings()` for parsing from
-> multiple string representations, for values we only need output, so `type_name` suffices.
-
 #### Implementation (vecdb)
 
-Added `short_type_name<T>()` helper in `traits/printable.rs`:
+Added `short_type_name<T>()` helper and `value_type_to_string()` to `AnyVec` trait.
-
-```rust
-pub fn short_type_name<T: 'static>() -> &'static str {
-    static CACHE: OnceLock<Mutex<HashMap<&'static str, &'static str>>> = OnceLock::new();
-
-    let full: &'static str = std::any::type_name::<T>();
-    // ... caching logic, extracts "Sats" from "brk_types::sats::Sats"
-}
-```
-
-Added `value_type_to_string()` to `AnyVec` trait in `traits/any.rs`:
-
-```rust
-pub trait AnyVec: Send + Sync {
-    // ... existing methods
-    fn value_type_to_string(&self) -> &'static str;
-}
-```
-
-Implemented in all vec variants:
-- `variants/eager/mod.rs`
-- `variants/lazy/from1/mod.rs`, `from2/mod.rs`, `from3/mod.rs`
-- `variants/raw/inner/mod.rs`
-- `variants/compressed/inner/mod.rs`
-- `variants/macros.rs` (for wrapper types)
-
-```rust
-fn value_type_to_string(&self) -> &'static str {
-    short_type_name::<V::T>()
-}
-```
-
-**No changes needed to brk_types** - works automatically for all types.
 
 ### Result
 
@@ -219,26 +166,11 @@ for (metric_name, index_to_vec) in &vecs.metric_to_index_to_vec {
 }
 ```
 
-This enables fully typed client generation.
-
 ## TreeNode Enhancement ✅ IMPLEMENTED
 
-### The Problem
-
-`TreeNode::Leaf` originally held just a `String` (the metric name), losing type and index information.
-
-### The Solution
-
 Changed `TreeNode::Leaf(String)` to `TreeNode::Leaf(MetricLeafWithSchema)` where:
 
 ```rust
-#[derive(Debug, Clone, Serialize, PartialEq, Eq, JsonSchema)]
-pub struct MetricLeaf {
-    pub name: String,
-    pub value_type: String,
-    pub indexes: BTreeSet<Index>,
-}
-
 #[derive(Debug, Clone, Serialize, JsonSchema)]
 pub struct MetricLeafWithSchema {
     #[serde(flatten)]
@@ -248,113 +180,68 @@ pub struct MetricLeafWithSchema {
 }
 ```
 
-#### Implementation
+## OpenAPI Integration ✅ IMPLEMENTED
 
-**brk_types/src/treenode.rs**:
+### Flow
-- Added `MetricLeaf` struct with `name`, `value_type`, and `indexes`
-- Added `MetricLeafWithSchema` wrapper with JSON schema
-- Helper methods: `name()`, `value_type()`, `indexes()`, `is_same_metric()`, `merge_indexes()`
-- Updated `TreeNode` enum to use `Leaf(MetricLeafWithSchema)`
 
-**brk_traversable/src/lib.rs**:
+1. brk_server creates OpenAPI spec via aide
-- Added `make_leaf<I, T, V>()` helper that creates `MetricLeafWithSchema` with schema from schemars
+2. On startup, serializes spec to JSON string
-- Updated all `Traversable::to_tree_node()` implementations with `JsonSchema` bounds
+3. Passes JSON to `brk_binder::generate_clients()`
-- Schema generated via `schemars::SchemaGenerator::default().into_root_schema_for::<T>()`
+4. brk_binder parses with `oas3` crate (supports OpenAPI 3.1)
+5. Generates typed methods for all GET endpoints
 
-**vecdb** (schemars feature):
+### Why oas3?
-- Added optional `schemars` dependency
-- Added `AnySchemaVec` trait with blanket impl for `TypedVec where T: JsonSchema`
 
-### Result
+aide generates OpenAPI 3.1 specs. The `openapiv3` crate only supports 3.0.x.
-
+The `oas3` crate supports OpenAPI 3.1.x parsing.
-The catalog tree now includes full type information and JSON schema at each leaf:
-
-```rust
-TreeNode::Leaf(MetricLeafWithSchema {
-    leaf: MetricLeaf {
-        name: "difficulty".to_string(),
-        value_type: "StoredF64".to_string(),
-        indexes: btreeset![Index::Height, Index::Date],
-    },
-    schema: json!({ "type": "number" }),  // schemars-generated
-})
-```
-
-When trees are merged/simplified, indexes are unioned together.
-
-### 2. Async Runtime
-
-- TypeScript: Native `Promise`
-- Python: `asyncio` or sync variant?
-- Rust: `tokio` assumed, or feature-flag for other runtimes?
-
-### 3. Error Handling
-
-- HTTP errors (4xx, 5xx)
-- Deserialization errors
-- Network errors
-- Should errors be typed per language?
-
-### 4. Additional Client Features
-
-- Request timeout configuration
-- Retry logic
-- Rate limiting
-- Caching
-- Batch requests (fetch multiple metrics at once)
 
 ## Tasks
 
 ### Phase 0: Type Infrastructure ✅ COMPLETE
 
-- [x] **vecdb**: Add `short_type_name<T>()` helper in `traits/printable.rs`
+- [x] vecdb: Add `short_type_name<T>()` and `value_type_to_string()`
-- [x] **vecdb**: Add `value_type_to_string()` to `AnyVec` trait
+- [x] vecdb: Add optional `schemars` feature with `AnySchemaVec` trait
-- [x] **vecdb**: Implement in all vec variants (eager, lazy, raw, compressed, macros)
+- [x] brk_types: Enhance `TreeNode::Leaf` to include `MetricLeafWithSchema`
-- [x] **vecdb**: Add optional `schemars` feature with `AnySchemaVec` trait
+- [x] brk_traversable: Update all `to_tree_node()` with schemars integration
-- [x] **brk_types**: Enhance `TreeNode::Leaf` to include `MetricLeafWithSchema`
+- [x] brk_binder: Set up generator module structure
-- [x] **brk_types**: Add `JsonSchema` derives to all value types
-- [x] **brk_traversable**: Update all `to_tree_node()` implementations with schemars integration
-- [x] **brk_query**: Export `Vecs` publicly for client generation
-- [x] **brk_binder**: Set up generator module structure
-- [x] **brk**: Verify compilation
 
 ### Phase 1: JavaScript Client ✅ COMPLETE
 
 - [x] Define `MetricNode` class with JSDoc generics
 - [x] Define `BrkClient` with base HTTP functionality
-- [x] Implement `ClientMetadata::from_vecs()` to extract metadata
 - [x] Generate `client.js` with full JSDoc type annotations
-- [x] Use `schema_to_jsdoc()` to convert JSON schemas to JSDoc types
 - [x] Tree navigation: `client.tree.category.metric.fetch()`
+- [x] API methods from OpenAPI endpoints
 
-### Phase 2: OpenAPI Integration (NEXT)
+### Phase 2: OpenAPI Integration ✅ COMPLETE
 
-- [ ] Add `openapiv3` crate dependency
+- [x] Add `oas3` crate dependency (OpenAPI 3.1 support)
-- [ ] Parse OpenAPI spec from aide (brk_server generates this)
+- [x] brk_server passes OpenAPI JSON to brk_binder on startup
-- [ ] Extract non-metric endpoint definitions (health, info, catalog, etc.)
+- [x] Parse OpenAPI spec and extract endpoint definitions
-- [ ] Generate methods for each endpoint with proper types
+- [x] Generate typed methods for each GET endpoint
-- [ ] Merge with tree-based metric access
 
-### Phase 3: Python Client
+### Phase 3: Python Client ✅ COMPLETE
 
-- [ ] Define `MetricNode` class with type hints
+- [x] Define `MetricNode` class with type hints
-- [ ] Define `BrkClient` with httpx/aiohttp
+- [x] Define `BrkClient` with httpx
-- [ ] Generate typed methods from OpenAPI
+- [x] Generate typed methods from OpenAPI
-- [ ] Generate tree navigation
+- [x] Generate tree navigation
 
-### Phase 4: Rust Client
+### Phase 4: Rust Client ✅ COMPLETE
 
-- [ ] Define `MetricNode<T>` struct using `brk_types`
+- [x] Define `MetricNode<T>` struct with lifetimes
-- [ ] Define `BrkClient` with reqwest
+- [x] Define `BrkClient` with reqwest (blocking)
-- [ ] Import types from `brk_types` instead of generating
+- [x] Generate tree navigation with proper lifetimes
-- [ ] Generate tree navigation with proper lifetimes
+- [x] Generate typed methods from OpenAPI
 
 ### Phase 5: Polish
 
+- [x] Switch from `openapiv3` to `oas3` crate
 - [ ] Error types per language
 - [ ] Documentation generation
 - [ ] Tests
 - [ ] Example usage in each language
+- [ ] Async Rust client variant
 
 ## File Structure
 
@@ -363,16 +250,26 @@ crates/brk_binder/
 ├── src/
 │   ├── lib.rs
 │   ├── js.rs              # JS constants generation (existing)
-│   ├── tree.rs         # Pattern extraction (reference only, not compiled)
 │   └── generator/
-│       ├── mod.rs
+│       ├── mod.rs         # generate_clients() entry point
-│       ├── types.rs    # ClientMetadata, MetricInfo, IndexPattern, schema_to_jsdoc
+│       ├── types.rs       # ClientMetadata, MetricInfo, IndexPattern
-│       ├── javascript.rs  # JavaScript + JSDoc client generation ✅
+│       ├── openapi.rs     # OpenAPI 3.1 spec parsing (oas3)
-│       ├── python.rs      # Python client generation (stub)
+│       ├── javascript.rs  # JavaScript + JSDoc client ✅
-│       └── rust.rs        # Rust client generation (stub)
+│       ├── python.rs      # Python client ✅
+│       └── rust.rs        # Rust client ✅
+├── clients/               # Generated output (gitignored)
+│   ├── javascript/
+│   ├── python/
+│   └── rust/
 ├── Cargo.toml
 ├── README.md
-└── DESIGN.md           # This file
+└── DESIGN.md
+
+crates/brk_server/
+└── src/
+    ├── lib.rs             # Calls brk_binder::generate_clients() on startup
+    └── api/
+        └── openapi.rs     # create_openapi() for aide
 ```
 
 ## Dependencies
@@ -381,11 +278,19 @@ crates/brk_binder/
 [dependencies]
 brk_query = { workspace = true }
 brk_types = { workspace = true }
+oas3 = "0.20"                # OpenAPI 3.1 spec parsing
 schemars = { workspace = true }
 serde_json = { workspace = true }
-vecdb = { workspace = true }
+```
-
+
-# For OpenAPI integration (Phase 2):
+## Usage
-# openapiv3 = "2"         # OpenAPI parsing
+
-# serde_yaml = "0.9"      # If parsing YAML specs
+To generate clients:
+
+```bash
+# Create the output directory
+mkdir -p crates/brk_binder/clients
+
+# Run the server (generates clients on startup)
+cargo run -p brk_server
 ```

crates/brk_binder/src/generator/javascript.rs

@@ -1,69 +1,105 @@
+use std::collections::HashSet;
 use std::fmt::Write as FmtWrite;
 use std::fs;
 use std::io;
 use std::path::Path;
 
-use brk_types::TreeNode;
+use brk_types::{Index, TreeNode};
 
-use super::{schema_to_jsdoc, to_camel_case, ClientMetadata, IndexPattern};
+use super::{ClientMetadata, Endpoint, IndexSetPattern, PatternField, StructuralPattern, get_node_fields, to_camel_case, to_pascal_case, to_snake_case};
 
-/// Generate JavaScript + JSDoc client from metadata
+/// Generate JavaScript + JSDoc client from metadata and OpenAPI endpoints
-pub fn generate_javascript_client(metadata: &ClientMetadata, output_dir: &Path) -> io::Result<()> {
+pub fn generate_javascript_client(
+    metadata: &ClientMetadata,
+    endpoints: &[Endpoint],
+    output_dir: &Path,
+) -> io::Result<()> {
     let mut output = String::new();
 
     // Header
     writeln!(output, "// Auto-generated BRK JavaScript client").unwrap();
     writeln!(output, "// Do not edit manually\n").unwrap();
 
-    // Generate pattern JSDoc typedefs for index groupings
-    generate_pattern_typedefs(&mut output, &metadata.patterns);
-
     // Generate the base client class
     generate_base_client(&mut output);
 
-    // Generate tree JSDoc typedefs from catalog
+    // Generate index accessor factory functions
-    generate_tree_typedefs(&mut output, &metadata.catalog);
+    generate_index_accessors(&mut output, &metadata.index_set_patterns);
 
-    // Generate the main client class with tree
+    // Generate structural pattern factory functions
-    generate_main_client(&mut output, &metadata.catalog);
+    generate_structural_patterns(&mut output, &metadata.structural_patterns, metadata);
+
+    // Generate tree JSDoc typedefs
+    generate_tree_typedefs(&mut output, &metadata.catalog, metadata);
+
+    // Generate the main client class with tree and API methods
+    generate_main_client(&mut output, &metadata.catalog, metadata, endpoints);
 
     fs::write(output_dir.join("client.js"), output)?;
 
     Ok(())
 }
 
-/// Generate JSDoc typedefs for common index patterns
-fn generate_pattern_typedefs(output: &mut String, patterns: &[IndexPattern]) {
-    writeln!(output, "// Index pattern typedefs").unwrap();
-    writeln!(output, "// Reusable patterns for metrics with the same index groupings\n").unwrap();
-
-    for pattern in patterns {
-        let pattern_name = pattern_to_name(pattern);
-        writeln!(output, "/**").unwrap();
-        writeln!(output, " * @template T").unwrap();
-        writeln!(output, " * @typedef {{Object}} {}", pattern_name).unwrap();
-
-        for index in &pattern.indexes {
-            let field_name = to_camel_case(&index.serialize_long());
-            writeln!(output, " * @property {{MetricNode<T>}} {}", field_name).unwrap();
-        }
-
-        writeln!(output, " */\n").unwrap();
-    }
-}
-
 /// Generate the base BrkClient class with HTTP functionality
 fn generate_base_client(output: &mut String) {
     writeln!(
         output,
         r#"/**
  * @typedef {{Object}} BrkClientOptions
- * @property {{string}} baseUrl - The base URL for the API
+ * @property {{string}} baseUrl - Base URL for the API
- * @property {{number}} [timeout] - Request timeout in ms (default: 30000)
+ * @property {{number}} [timeout] - Request timeout in milliseconds
  */
 
 /**
- * Base HTTP client
+ * Custom error class for BRK client errors
+ */
+class BrkError extends Error {{
+  /**
+   * @param {{string}} message
+   * @param {{number}} [status]
+   */
+  constructor(message, status) {{
+    super(message);
+    this.name = 'BrkError';
+    this.status = status;
+  }}
+}}
+
+/**
+ * A metric node that can fetch data for different indexes.
+ * @template T
+ */
+class MetricNode {{
+  /**
+   * @param {{BrkClientBase}} client
+   * @param {{string}} path
+   */
+  constructor(client, path) {{
+    this.client = client;
+    this.path = path;
+  }}
+
+  /**
+   * Fetch all data points for this metric.
+   * @returns {{Promise<T[]>}}
+   */
+  async get() {{
+    return this.client.get(this.path);
+  }}
+
+  /**
+   * Fetch data points within a date range.
+   * @param {{string}} from
+   * @param {{string}} to
+   * @returns {{Promise<T[]>}}
+   */
+  async getRange(from, to) {{
+    return this.client.get(`${{this.path}}?from=${{from}}&to=${{to}}`);
+  }}
+}}
+
+/**
+ * Base HTTP client for making requests
  */
 class BrkClientBase {{
   /**
@@ -71,15 +107,16 @@ class BrkClientBase {{
    */
   constructor(options) {{
     if (typeof options === 'string') {{
-      this.baseUrl = options.replace(/\/$/, '');
+      this.baseUrl = options;
       this.timeout = 30000;
     }} else {{
-      this.baseUrl = options.baseUrl.replace(/\/$/, '');
+      this.baseUrl = options.baseUrl;
-      this.timeout = options.timeout ?? 30000;
+      this.timeout = options.timeout || 30000;
     }}
   }}
 
   /**
+   * Make a GET request
    * @template T
    * @param {{string}} path
    * @returns {{Promise<T>}}
@@ -91,127 +128,241 @@ class BrkClientBase {{
     try {{
       const response = await fetch(`${{this.baseUrl}}${{path}}`, {{
         signal: controller.signal,
-        headers: {{ 'Accept': 'application/json' }},
       }});
 
       if (!response.ok) {{
-        throw new BrkError(`HTTP ${{response.status}}: ${{response.statusText}}`, response.status);
+        throw new BrkError(`HTTP error: ${{response.status}}`, response.status);
       }}
 
-      return await response.json();
+      return response.json();
+    }} catch (error) {{
+      if (error.name === 'AbortError') {{
+        throw new BrkError('Request timeout');
+      }}
+      throw error;
     }} finally {{
       clearTimeout(timeoutId);
     }}
   }}
 }}
 
-/**
- * Error class for BRK API errors
- */
-class BrkError extends Error {{
-  /**
-   * @param {{string}} message
-   * @param {{number}} [statusCode]
-   */
-  constructor(message, statusCode) {{
-    super(message);
-    this.name = 'BrkError';
-    this.statusCode = statusCode;
-  }}
-}}
-
-/**
- * Metric node with fetch capability
- * @template T
- */
-class MetricNode {{
-  /**
-   * @param {{BrkClientBase}} client
-   * @param {{string}} path
-   */
-  constructor(client, path) {{
-    this._client = client;
-    this._path = path;
-  }}
-
-  /**
-   * Fetch the metric value
-   * @returns {{Promise<T>}}
-   */
-  async fetch() {{
-    return this._client.get(this._path);
-  }}
-
-  toString() {{
-    return this._path;
-  }}
-}}
-
 "#
     )
     .unwrap();
 }
 
-/// Generate JSDoc typedefs for the catalog tree
+/// Generate index accessor factory functions
-fn generate_tree_typedefs(output: &mut String, catalog: &TreeNode) {
+fn generate_index_accessors(output: &mut String, patterns: &[IndexSetPattern]) {
-    writeln!(output, "// Catalog tree typedefs\n").unwrap();
+    if patterns.is_empty() {
-    generate_node_typedef(output, "CatalogTree", catalog, "");
+        return;
     }
 
-/// Recursively generate typedef for a tree node
+    writeln!(output, "// Index accessor factory functions\n").unwrap();
-fn generate_node_typedef(output: &mut String, name: &str, node: &TreeNode, path: &str) {
+
-    match node {
+    for pattern in patterns {
-        TreeNode::Leaf(_leaf) => {
+        // Generate JSDoc typedef for the accessor
-            // Leaf nodes are MetricNode<ValueType>
+        writeln!(output, "/**").unwrap();
-            // No separate typedef needed, handled inline
+        writeln!(output, " * @template T").unwrap();
+        writeln!(output, " * @typedef {{Object}} {}", pattern.name).unwrap();
+        for index in &pattern.indexes {
+            let field_name = index_to_camel_case(index);
+            writeln!(output, " * @property {{MetricNode<T>}} {}", field_name).unwrap();
         }
-        TreeNode::Branch(children) => {
+        writeln!(output, " */\n").unwrap();
+
+        // Generate factory function
+        writeln!(output, "/**").unwrap();
+        writeln!(output, " * Create a {} accessor", pattern.name).unwrap();
+        writeln!(output, " * @template T").unwrap();
+        writeln!(output, " * @param {{BrkClientBase}} client").unwrap();
+        writeln!(output, " * @param {{string}} basePath").unwrap();
+        writeln!(output, " * @returns {{{}<T>}}", pattern.name).unwrap();
+        writeln!(output, " */").unwrap();
+        writeln!(output, "function create{}(client, basePath) {{", pattern.name).unwrap();
+        writeln!(output, "  return {{").unwrap();
+
+        for (i, index) in pattern.indexes.iter().enumerate() {
+            let field_name = index_to_camel_case(index);
+            let path_segment = index.serialize_short();
+            let comma = if i < pattern.indexes.len() - 1 { "," } else { "" };
+            writeln!(
+                output,
+                "    {}: new MetricNode(client, `${{basePath}}/{}`){}",
+                field_name, path_segment, comma
+            ).unwrap();
+        }
+
+        writeln!(output, "  }};").unwrap();
+        writeln!(output, "}}\n").unwrap();
+    }
+}
+
+/// Convert an Index to a camelCase field name (e.g., DateIndex -> byDate)
+fn index_to_camel_case(index: &Index) -> String {
+    let short = index.serialize_short();
+    format!("by{}", to_pascal_case(&to_snake_case(short)))
+}
+
+/// Generate structural pattern factory functions
+fn generate_structural_patterns(output: &mut String, patterns: &[StructuralPattern], metadata: &ClientMetadata) {
+    if patterns.is_empty() {
+        return;
+    }
+
+    writeln!(output, "// Reusable structural pattern factories\n").unwrap();
+
+    for pattern in patterns {
+        // Generate JSDoc typedef
+        writeln!(output, "/**").unwrap();
+        writeln!(output, " * @typedef {{Object}} {}", pattern.name).unwrap();
+        for field in &pattern.fields {
+            let js_type = field_to_js_type(field, metadata);
+            writeln!(output, " * @property {{{}}} {}", js_type, to_camel_case(&field.name)).unwrap();
+        }
+        writeln!(output, " */\n").unwrap();
+
+        // Generate factory function
+        writeln!(output, "/**").unwrap();
+        writeln!(output, " * Create a {} pattern node", pattern.name).unwrap();
+        writeln!(output, " * @param {{BrkClientBase}} client").unwrap();
+        writeln!(output, " * @param {{string}} basePath").unwrap();
+        writeln!(output, " * @returns {{{}}}", pattern.name).unwrap();
+        writeln!(output, " */").unwrap();
+        writeln!(output, "function create{}(client, basePath) {{", pattern.name).unwrap();
+        writeln!(output, "  return {{").unwrap();
+
+        for (i, field) in pattern.fields.iter().enumerate() {
+            let comma = if i < pattern.fields.len() - 1 { "," } else { "" };
+            if metadata.is_pattern_type(&field.rust_type) {
+                writeln!(
+                    output,
+                    "    {}: create{}(client, `${{basePath}}/{}`){}",
+                    to_camel_case(&field.name), field.rust_type, field.name, comma
+                ).unwrap();
+            } else if field_uses_accessor(field, metadata) {
+                let accessor = metadata.find_index_set_pattern(&field.indexes).unwrap();
+                writeln!(
+                    output,
+                    "    {}: create{}(client, `${{basePath}}/{}`){}",
+                    to_camel_case(&field.name), accessor.name, field.name, comma
+                ).unwrap();
+            } else {
+                writeln!(
+                    output,
+                    "    {}: new MetricNode(client, `${{basePath}}/{}`){}",
+                    to_camel_case(&field.name), field.name, comma
+                ).unwrap();
+            }
+        }
+
+        writeln!(output, "  }};").unwrap();
+        writeln!(output, "}}\n").unwrap();
+    }
+}
+
+/// Convert pattern field to JavaScript/JSDoc type
+fn field_to_js_type(field: &PatternField, metadata: &ClientMetadata) -> String {
+    if metadata.is_pattern_type(&field.rust_type) {
+        // Pattern type - use pattern name directly
+        field.rust_type.clone()
+    } else if let Some(accessor) = metadata.find_index_set_pattern(&field.indexes) {
+        // Leaf with a reusable accessor pattern
+        let js_type = json_type_to_js(&field.json_type);
+        format!("{}<{}>", accessor.name, js_type)
+    } else {
+        // Leaf with unique index set - use MetricNode directly
+        let js_type = json_type_to_js(&field.json_type);
+        format!("MetricNode<{}>", js_type)
+    }
+}
+
+/// Check if a field should use an index accessor
+fn field_uses_accessor(field: &PatternField, metadata: &ClientMetadata) -> bool {
+    metadata.find_index_set_pattern(&field.indexes).is_some()
+}
+
+/// Convert JSON Schema type to JSDoc type
+fn json_type_to_js(json_type: &str) -> &str {
+    match json_type {
+        "integer" | "number" => "number",
+        "boolean" => "boolean",
+        "string" => "string",
+        "array" => "Array",
+        "object" => "Object",
+        _ => "*",
+    }
+}
+
+/// Generate tree typedefs
+fn generate_tree_typedefs(
+    output: &mut String,
+    catalog: &TreeNode,
+    metadata: &ClientMetadata,
+) {
+    writeln!(output, "// Catalog tree typedefs\n").unwrap();
+
+    let pattern_lookup = metadata.pattern_lookup();
+    let mut generated = HashSet::new();
+    generate_tree_typedef(output, "CatalogTree", catalog, &pattern_lookup, metadata, &mut generated);
+}
+
+/// Recursively generate tree typedefs
+fn generate_tree_typedef(
+    output: &mut String,
+    name: &str,
+    node: &TreeNode,
+    pattern_lookup: &std::collections::HashMap<Vec<PatternField>, String>,
+    metadata: &ClientMetadata,
+    generated: &mut HashSet<String>,
+) {
+    if let TreeNode::Branch(children) = node {
+        // Build signature
+        let fields = get_node_fields(children, pattern_lookup);
+
+        // Skip if this matches a pattern (already generated)
+        if pattern_lookup.contains_key(&fields) && pattern_lookup.get(&fields) != Some(&name.to_string()) {
+            return;
+        }
+
+        if generated.contains(name) {
+            return;
+        }
+        generated.insert(name.to_string());
+
         writeln!(output, "/**").unwrap();
         writeln!(output, " * @typedef {{Object}} {}", name).unwrap();
 
-            for (child_name, child_node) in children {
+        for field in &fields {
-                let field_name = to_camel_case(child_name);
+            let js_type = field_to_js_type(field, metadata);
-
+            writeln!(output, " * @property {{{}}} {}", js_type, to_camel_case(&field.name)).unwrap();
-                match child_node {
-                    TreeNode::Leaf(leaf) => {
-                        let js_type = schema_to_jsdoc(&leaf.schema);
-                        writeln!(
-                            output,
-                            " * @property {{MetricNode<{}>}} {}",
-                            js_type, field_name
-                        )
-                        .unwrap();
-                    }
-                    TreeNode::Branch(_) => {
-                        let child_type_name = format!("{}_{}", name, to_pascal_case(child_name));
-                        writeln!(output, " * @property {{{}}} {}", child_type_name, field_name)
-                            .unwrap();
-                    }
-                }
         }
 
         writeln!(output, " */\n").unwrap();
 
         // Generate child typedefs
         for (child_name, child_node) in children {
-                if let TreeNode::Branch(_) = child_node {
+            if let TreeNode::Branch(grandchildren) = child_node {
+                let child_fields = get_node_fields(grandchildren, pattern_lookup);
+                if !pattern_lookup.contains_key(&child_fields) {
                     let child_type_name = format!("{}_{}", name, to_pascal_case(child_name));
-                    let child_path = if path.is_empty() {
+                    generate_tree_typedef(output, &child_type_name, child_node, pattern_lookup, metadata, generated);
-                        format!("/{}", child_name)
-                    } else {
-                        format!("{}/{}", path, child_name)
-                    };
-                    generate_node_typedef(output, &child_type_name, child_node, &child_path);
                 }
             }
         }
     }
 }
 
-/// Generate the main client class with initialized tree
+/// Generate main client
-fn generate_main_client(output: &mut String, catalog: &TreeNode) {
+fn generate_main_client(
+    output: &mut String,
+    catalog: &TreeNode,
+    metadata: &ClientMetadata,
+    endpoints: &[Endpoint],
+) {
+    let pattern_lookup = metadata.pattern_lookup();
+
     writeln!(output, "/**").unwrap();
-    writeln!(output, " * Main BRK client with catalog tree").unwrap();
+    writeln!(output, " * Main BRK client with catalog tree and API methods").unwrap();
     writeln!(output, " * @extends BrkClientBase").unwrap();
     writeln!(output, " */").unwrap();
     writeln!(output, "class BrkClient extends BrkClientBase {{").unwrap();
@@ -221,27 +372,39 @@ fn generate_main_client(output: &mut String, catalog: &TreeNode) {
     writeln!(output, "  constructor(options) {{").unwrap();
     writeln!(output, "    super(options);").unwrap();
     writeln!(output, "    /** @type {{CatalogTree}} */").unwrap();
-    writeln!(output, "    this.tree = this._buildTree();").unwrap();
+    writeln!(output, "    this.tree = this._buildTree('');").unwrap();
     writeln!(output, "  }}\n").unwrap();
 
     // Generate _buildTree method
     writeln!(output, "  /**").unwrap();
     writeln!(output, "   * @private").unwrap();
+    writeln!(output, "   * @param {{string}} basePath").unwrap();
     writeln!(output, "   * @returns {{CatalogTree}}").unwrap();
     writeln!(output, "   */").unwrap();
-    writeln!(output, "  _buildTree() {{").unwrap();
+    writeln!(output, "  _buildTree(basePath) {{").unwrap();
     writeln!(output, "    return {{").unwrap();
-    generate_tree_initializer(output, catalog, "", 3);
+    generate_tree_initializer(output, catalog, "", 3, &pattern_lookup, metadata);
     writeln!(output, "    }};").unwrap();
-    writeln!(output, "  }}").unwrap();
     writeln!(output, "  }}\n").unwrap();
 
-    // Export for ES modules
+    // Generate API methods
+    generate_api_methods(output, endpoints);
+
+    writeln!(output, "}}\n").unwrap();
+
+    // Export
     writeln!(output, "export {{ BrkClient, BrkClientBase, BrkError, MetricNode }};").unwrap();
 }
 
-/// Generate the tree initializer code
+/// Generate tree initializer
-fn generate_tree_initializer(output: &mut String, node: &TreeNode, path: &str, indent: usize) {
+fn generate_tree_initializer(
+    output: &mut String,
+    node: &TreeNode,
+    path: &str,
+    indent: usize,
+    pattern_lookup: &std::collections::HashMap<Vec<PatternField>, String>,
+    metadata: &ClientMetadata,
+) {
     let indent_str = "  ".repeat(indent);
 
     if let TreeNode::Branch(children) = node {
@@ -256,43 +419,118 @@ fn generate_tree_initializer(output: &mut String, node: &TreeNode, path: &str, i
             let comma = if i < children.len() - 1 { "," } else { "" };
 
             match child_node {
-                TreeNode::Leaf(_) => {
+                TreeNode::Leaf(leaf) => {
+                    if let Some(accessor) = metadata.find_index_set_pattern(leaf.indexes()) {
+                        writeln!(
+                            output,
+                            "{}{}: create{}(this, '{}'){}",
+                            indent_str, field_name, accessor.name, child_path, comma
+                        ).unwrap();
+                    } else {
                         writeln!(
                             output,
                             "{}{}: new MetricNode(this, '{}'){}",
                             indent_str, field_name, child_path, comma
-                    )
+                        ).unwrap();
-                    .unwrap();
                     }
-                TreeNode::Branch(_) => {
+                }
+                TreeNode::Branch(grandchildren) => {
+                    let child_fields = get_node_fields(grandchildren, pattern_lookup);
+                    if let Some(pattern_name) = pattern_lookup.get(&child_fields) {
+                        writeln!(
+                            output,
+                            "{}{}: create{}(this, '{}'){}",
+                            indent_str, field_name, pattern_name, child_path, comma
+                        ).unwrap();
+                    } else {
                         writeln!(output, "{}{}: {{", indent_str, field_name).unwrap();
-                    generate_tree_initializer(output, child_node, &child_path, indent + 1);
+                        generate_tree_initializer(output, child_node, &child_path, indent + 1, pattern_lookup, metadata);
                         writeln!(output, "{}}}{}", indent_str, comma).unwrap();
                     }
                 }
             }
         }
     }
-
-/// Convert pattern to a JSDoc typedef name
-fn pattern_to_name(pattern: &IndexPattern) -> String {
-    let index_names: Vec<String> = pattern
-        .indexes
-        .iter()
-        .map(|i| to_pascal_case(&i.serialize_long()))
-        .collect();
-    format!("Pattern_{}", index_names.join("_"))
 }
 
-/// Convert string to PascalCase
+/// Generate API methods
-fn to_pascal_case(s: &str) -> String {
+fn generate_api_methods(output: &mut String, endpoints: &[Endpoint]) {
-    s.split('_')
+    for endpoint in endpoints {
-        .map(|word| {
+        if endpoint.method != "GET" {
-            let mut chars = word.chars();
+            continue;
-            match chars.next() {
-                None => String::new(),
-                Some(first) => first.to_uppercase().collect::<String>() + chars.as_str(),
         }
-        })
+
-        .collect()
+        let method_name = endpoint_to_method_name(endpoint);
+        let return_type = endpoint.response_type.as_deref().unwrap_or("*");
+
+        writeln!(output, "  /**").unwrap();
+        if let Some(summary) = &endpoint.summary {
+            writeln!(output, "   * {}", summary).unwrap();
         }
+
+        for param in &endpoint.path_params {
+            let desc = param.description.as_deref().unwrap_or("");
+            writeln!(output, "   * @param {{{}}} {} {}", param.param_type, param.name, desc).unwrap();
+        }
+        for param in &endpoint.query_params {
+            let optional = if param.required { "" } else { "=" };
+            let desc = param.description.as_deref().unwrap_or("");
+            writeln!(output, "   * @param {{{}{}}} [{}] {}", param.param_type, optional, param.name, desc).unwrap();
+        }
+
+        writeln!(output, "   * @returns {{Promise<{}>}}", return_type).unwrap();
+        writeln!(output, "   */").unwrap();
+
+        let params = build_method_params(endpoint);
+        writeln!(output, "  async {}({}) {{", method_name, params).unwrap();
+
+        let path = build_path_template(&endpoint.path, &endpoint.path_params);
+
+        if endpoint.query_params.is_empty() {
+            writeln!(output, "    return this.get(`{}`);", path).unwrap();
+        } else {
+            writeln!(output, "    const params = new URLSearchParams();").unwrap();
+            for param in &endpoint.query_params {
+                if param.required {
+                    writeln!(output, "    params.set('{}', String({}));", param.name, param.name).unwrap();
+                } else {
+                    writeln!(output, "    if ({} !== undefined) params.set('{}', String({}));", param.name, param.name, param.name).unwrap();
+                }
+            }
+            writeln!(output, "    const query = params.toString();").unwrap();
+            writeln!(output, "    return this.get(`{}${{query ? '?' + query : ''}}`);", path).unwrap();
+        }
+
+        writeln!(output, "  }}\n").unwrap();
+    }
+}
+
+fn endpoint_to_method_name(endpoint: &Endpoint) -> String {
+    if let Some(op_id) = &endpoint.operation_id {
+        return to_camel_case(op_id);
+    }
+    let parts: Vec<&str> = endpoint.path.split('/').filter(|s| !s.is_empty() && !s.starts_with('{')).collect();
+    format!("get{}", to_pascal_case(&parts.join("_")))
+}
+
+fn build_method_params(endpoint: &Endpoint) -> String {
+    let mut params = Vec::new();
+    for param in &endpoint.path_params {
+        params.push(param.name.clone());
+    }
+    for param in &endpoint.query_params {
+        params.push(param.name.clone());
+    }
+    params.join(", ")
+}
+
+fn build_path_template(path: &str, path_params: &[super::Parameter]) -> String {
+    let mut result = path.to_string();
+    for param in path_params {
+        let placeholder = format!("{{{}}}", param.name);
+        let interpolation = format!("${{{}}}", param.name);
+        result = result.replace(&placeholder, &interpolation);
+    }
+    result
+}
+

crates/brk_binder/src/generator/mod.rs

@@ -1,35 +1,41 @@
 mod javascript;
+mod openapi;
 mod python;
 mod rust;
 mod types;
 
-pub use javascript::generate_javascript_client;
+pub use javascript::*;
-pub use python::generate_python_client;
+pub use openapi::*;
-pub use rust::generate_rust_client;
+pub use python::*;
+pub use rust::*;
 pub use types::*;
 
 use brk_query::Vecs;
 use std::io;
 use std::path::Path;
 
-/// Generate all client libraries from the query vecs
+/// Generate all client libraries from the query vecs and OpenAPI JSON
-pub fn generate_clients(vecs: &Vecs, output_dir: &Path) -> io::Result<()> {
+pub fn generate_clients(vecs: &Vecs, openapi_json: &str, output_dir: &Path) -> io::Result<()> {
     let metadata = ClientMetadata::from_vecs(vecs);
 
+    // Parse OpenAPI spec from JSON
+    let spec = parse_openapi_json(openapi_json)?;
+    let endpoints = extract_endpoints(&spec);
+
     // Generate Rust client
     let rust_path = output_dir.join("rust");
     std::fs::create_dir_all(&rust_path)?;
-    generate_rust_client(&metadata, &rust_path)?;
+    generate_rust_client(&metadata, &endpoints, &rust_path)?;
 
     // Generate JavaScript client
     let js_path = output_dir.join("javascript");
     std::fs::create_dir_all(&js_path)?;
-    generate_javascript_client(&metadata, &js_path)?;
+    generate_javascript_client(&metadata, &endpoints, &js_path)?;
 
     // Generate Python client
     let python_path = output_dir.join("python");
     std::fs::create_dir_all(&python_path)?;
-    generate_python_client(&metadata, &python_path)?;
+    generate_python_client(&metadata, &endpoints, &python_path)?;
 
     Ok(())
 }

crates/brk_binder/src/generator/openapi.rs

@@ -0,0 +1,214 @@
+use std::io;
+
+use oas3::spec::{ObjectOrReference, Operation, ParameterIn, PathItem, Schema, SchemaTypeSet};
+use oas3::Spec;
+use serde_json::Value;
+
+/// Endpoint information extracted from OpenAPI spec
+#[derive(Debug, Clone)]
+pub struct Endpoint {
+    /// HTTP method (GET, POST, etc.)
+    pub method: String,
+    /// Path template (e.g., "/blocks/{hash}")
+    pub path: String,
+    /// Operation ID (e.g., "getBlockByHash")
+    pub operation_id: Option<String>,
+    /// Summary/description
+    pub summary: Option<String>,
+    /// Tags for grouping
+    pub tags: Vec<String>,
+    /// Path parameters
+    pub path_params: Vec<Parameter>,
+    /// Query parameters
+    pub query_params: Vec<Parameter>,
+    /// Response type (simplified)
+    pub response_type: Option<String>,
+}
+
+/// Parameter information
+#[derive(Debug, Clone)]
+pub struct Parameter {
+    pub name: String,
+    pub required: bool,
+    pub param_type: String,
+    pub description: Option<String>,
+}
+
+/// Parse OpenAPI spec from JSON string
+///
+/// Pre-processes the JSON to handle oas3 limitations:
+/// - Removes unsupported siblings from `$ref` objects (oas3 only supports `summary` and `description`)
+pub fn parse_openapi_json(json: &str) -> io::Result<Spec> {
+    let mut value: Value =
+        serde_json::from_str(json).map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))?;
+
+    // Clean up for oas3 compatibility
+    clean_for_oas3(&mut value);
+
+    let cleaned_json = serde_json::to_string(&value)
+        .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))?;
+
+    oas3::from_json(&cleaned_json).map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))
+}
+
+/// Clean up OpenAPI spec for oas3 compatibility.
+/// - Removes unsupported siblings from $ref objects (oas3 only supports summary and description)
+/// - Converts boolean schemas to object schemas (oas3 doesn't handle `"schema": true`)
+fn clean_for_oas3(value: &mut Value) {
+    match value {
+        Value::Object(map) => {
+            // Handle $ref with unsupported siblings
+            if map.contains_key("$ref") {
+                map.retain(|k, _| k == "$ref" || k == "summary" || k == "description");
+            } else {
+                // Convert boolean schemas to empty object schemas
+                if let Some(schema) = map.get_mut("schema") {
+                    if schema.is_boolean() {
+                        *schema = Value::Object(serde_json::Map::new());
+                    }
+                }
+                for v in map.values_mut() {
+                    clean_for_oas3(v);
+                }
+            }
+        }
+        Value::Array(arr) => {
+            for v in arr {
+                clean_for_oas3(v);
+            }
+        }
+        _ => {}
+    }
+}
+
+/// Extract all endpoints from OpenAPI spec
+pub fn extract_endpoints(spec: &Spec) -> Vec<Endpoint> {
+    let mut endpoints = Vec::new();
+
+    let Some(paths) = &spec.paths else {
+        return endpoints;
+    };
+
+    for (path, path_item) in paths {
+        for (method, operation) in get_operations(path_item) {
+            if let Some(endpoint) = extract_endpoint(path, &method, operation) {
+                endpoints.push(endpoint);
+            }
+        }
+    }
+
+    endpoints
+}
+
+fn get_operations(path_item: &PathItem) -> Vec<(String, &Operation)> {
+    let mut ops = Vec::new();
+    if let Some(op) = &path_item.get {
+        ops.push(("GET".to_string(), op));
+    }
+    if let Some(op) = &path_item.post {
+        ops.push(("POST".to_string(), op));
+    }
+    if let Some(op) = &path_item.put {
+        ops.push(("PUT".to_string(), op));
+    }
+    if let Some(op) = &path_item.delete {
+        ops.push(("DELETE".to_string(), op));
+    }
+    if let Some(op) = &path_item.patch {
+        ops.push(("PATCH".to_string(), op));
+    }
+    ops
+}
+
+fn extract_endpoint(path: &str, method: &str, operation: &Operation) -> Option<Endpoint> {
+    let path_params = extract_parameters(operation, ParameterIn::Path);
+    let query_params = extract_parameters(operation, ParameterIn::Query);
+
+    let response_type = extract_response_type(operation);
+
+    Some(Endpoint {
+        method: method.to_string(),
+        path: path.to_string(),
+        operation_id: operation.operation_id.clone(),
+        summary: operation.summary.clone().or_else(|| operation.description.clone()),
+        tags: operation.tags.clone(),
+        path_params,
+        query_params,
+        response_type,
+    })
+}
+
+fn extract_parameters(operation: &Operation, location: ParameterIn) -> Vec<Parameter> {
+    operation
+        .parameters
+        .iter()
+        .filter_map(|p| match p {
+            ObjectOrReference::Object(param) if param.location == location => Some(Parameter {
+                name: param.name.clone(),
+                required: param.required.unwrap_or(false),
+                param_type: "string".to_string(), // Simplified
+                description: param.description.clone(),
+            }),
+            _ => None,
+        })
+        .collect()
+}
+
+fn extract_response_type(operation: &Operation) -> Option<String> {
+    let responses = operation.responses.as_ref()?;
+
+    // Look for 200 OK response
+    let response = responses.get("200")?;
+
+    match response {
+        ObjectOrReference::Object(response) => {
+            // Look for JSON content
+            let content = response.content.get("application/json")?;
+
+            match &content.schema {
+                Some(ObjectOrReference::Ref { ref_path, .. }) => {
+                    // Extract type name from reference like "#/components/schemas/Block"
+                    Some(ref_path.rsplit('/').next()?.to_string())
+                }
+                Some(ObjectOrReference::Object(schema)) => schema_to_type_name(schema),
+                None => None,
+            }
+        }
+        ObjectOrReference::Ref { .. } => None,
+    }
+}
+
+fn schema_type_from_schema(schema: &Schema) -> Option<String> {
+    match schema {
+        Schema::Boolean(_) => Some("boolean".to_string()),
+        Schema::Object(obj_or_ref) => match obj_or_ref.as_ref() {
+            ObjectOrReference::Object(obj_schema) => schema_to_type_name(obj_schema),
+            ObjectOrReference::Ref { ref_path, .. } => {
+                ref_path.rsplit('/').next().map(|s| s.to_string())
+            }
+        },
+    }
+}
+
+fn schema_to_type_name(schema: &oas3::spec::ObjectSchema) -> Option<String> {
+    let schema_type = schema.schema_type.as_ref()?;
+
+    match schema_type {
+        SchemaTypeSet::Single(t) => match t {
+            oas3::spec::SchemaType::String => Some("string".to_string()),
+            oas3::spec::SchemaType::Number => Some("number".to_string()),
+            oas3::spec::SchemaType::Integer => Some("number".to_string()),
+            oas3::spec::SchemaType::Boolean => Some("boolean".to_string()),
+            oas3::spec::SchemaType::Array => {
+                let inner = match &schema.items {
+                    Some(boxed_schema) => schema_type_from_schema(boxed_schema),
+                    None => Some("*".to_string()),
+                };
+                inner.map(|t| format!("{}[]", t))
+            }
+            oas3::spec::SchemaType::Object => Some("Object".to_string()),
+            oas3::spec::SchemaType::Null => Some("null".to_string()),
+        },
+        SchemaTypeSet::Multiple(_) => Some("*".to_string()),
+    }
+}

crates/brk_binder/src/generator/python.rs

@@ -1,10 +1,428 @@
+use std::collections::HashSet;
+use std::fmt::Write as FmtWrite;
+use std::fs;
 use std::io;
 use std::path::Path;
 
-use super::ClientMetadata;
+use brk_types::{Index, TreeNode};
+
+use super::{ClientMetadata, Endpoint, IndexSetPattern, PatternField, StructuralPattern, get_node_fields, to_pascal_case, to_snake_case};
+
+/// Generate Python client from metadata and OpenAPI endpoints
+pub fn generate_python_client(
+    metadata: &ClientMetadata,
+    endpoints: &[Endpoint],
+    output_dir: &Path,
+) -> io::Result<()> {
+    let mut output = String::new();
+
+    // Header
+    writeln!(output, "# Auto-generated BRK Python client").unwrap();
+    writeln!(output, "# Do not edit manually\n").unwrap();
+    writeln!(output, "from __future__ import annotations").unwrap();
+    writeln!(output, "from typing import TypeVar, Generic, Any, Optional, List").unwrap();
+    writeln!(output, "from dataclasses import dataclass").unwrap();
+    writeln!(output, "import httpx\n").unwrap();
+
+    // Type variable for generic MetricNode
+    writeln!(output, "T = TypeVar('T')\n").unwrap();
+
+    // Generate base client class
+    generate_base_client(&mut output);
+
+    // Generate MetricNode class
+    generate_metric_node(&mut output);
+
+    // Generate index accessor classes
+    generate_index_accessors(&mut output, &metadata.index_set_patterns);
+
+    // Generate structural pattern classes
+    generate_structural_patterns(&mut output, &metadata.structural_patterns, metadata);
+
+    // Generate tree classes
+    generate_tree_classes(&mut output, &metadata.catalog, metadata);
+
+    // Generate main client with tree and API methods
+    generate_main_client(&mut output, endpoints);
+
+    fs::write(output_dir.join("client.py"), output)?;
 
-/// Generate Python client from metadata
-pub fn generate_python_client(_metadata: &ClientMetadata, _output_dir: &Path) -> io::Result<()> {
-    // TODO: Implement Python client generation
     Ok(())
 }
+
+/// Generate the base BrkClient class with HTTP functionality
+fn generate_base_client(output: &mut String) {
+    writeln!(
+        output,
+        r#"class BrkError(Exception):
+    """Custom error class for BRK client errors."""
+
+    def __init__(self, message: str, status: Optional[int] = None):
+        super().__init__(message)
+        self.status = status
+
+
+class BrkClientBase:
+    """Base HTTP client for making requests."""
+
+    def __init__(self, base_url: str, timeout: float = 30.0):
+        self.base_url = base_url
+        self.timeout = timeout
+        self._client = httpx.Client(timeout=timeout)
+
+    def get(self, path: str) -> Any:
+        """Make a GET request."""
+        try:
+            response = self._client.get(f"{{self.base_url}}{{path}}")
+            response.raise_for_status()
+            return response.json()
+        except httpx.HTTPStatusError as e:
+            raise BrkError(f"HTTP error: {{e.response.status_code}}", e.response.status_code)
+        except httpx.RequestError as e:
+            raise BrkError(str(e))
+
+    def close(self):
+        """Close the HTTP client."""
+        self._client.close()
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self.close()
+
+"#
+    )
+    .unwrap();
+}
+
+/// Generate the MetricNode class
+fn generate_metric_node(output: &mut String) {
+    writeln!(
+        output,
+        r#"class MetricNode(Generic[T]):
+    """A metric node that can fetch data for different indexes."""
+
+    def __init__(self, client: BrkClientBase, path: str):
+        self._client = client
+        self._path = path
+
+    def get(self) -> List[T]:
+        """Fetch all data points for this metric."""
+        return self._client.get(self._path)
+
+    def get_range(self, from_date: str, to_date: str) -> List[T]:
+        """Fetch data points within a date range."""
+        return self._client.get(f"{{self._path}}?from={{from_date}}&to={{to_date}}")
+
+"#
+    )
+    .unwrap();
+}
+
+/// Generate index accessor classes
+fn generate_index_accessors(output: &mut String, patterns: &[IndexSetPattern]) {
+    if patterns.is_empty() {
+        return;
+    }
+
+    writeln!(output, "# Index accessor classes\n").unwrap();
+
+    for pattern in patterns {
+        writeln!(output, "class {}(Generic[T]):", pattern.name).unwrap();
+        writeln!(output, "    \"\"\"Index accessor for metrics with {} indexes.\"\"\"", pattern.indexes.len()).unwrap();
+        writeln!(output, "    ").unwrap();
+        writeln!(output, "    def __init__(self, client: BrkClientBase, base_path: str):").unwrap();
+
+        for index in &pattern.indexes {
+            let field_name = index_to_snake_case(index);
+            let path_segment = index.serialize_short();
+            writeln!(
+                output,
+                "        self.{}: MetricNode[T] = MetricNode(client, f'{{base_path}}/{}')",
+                field_name, path_segment
+            ).unwrap();
+        }
+
+        writeln!(output).unwrap();
+    }
+}
+
+/// Convert an Index to a snake_case field name (e.g., DateIndex -> by_date)
+fn index_to_snake_case(index: &Index) -> String {
+    let short = index.serialize_short();
+    format!("by_{}", to_snake_case(short))
+}
+
+/// Generate structural pattern classes
+fn generate_structural_patterns(output: &mut String, patterns: &[StructuralPattern], metadata: &ClientMetadata) {
+    if patterns.is_empty() {
+        return;
+    }
+
+    writeln!(output, "# Reusable structural pattern classes\n").unwrap();
+
+    for pattern in patterns {
+        writeln!(output, "class {}:", pattern.name).unwrap();
+        writeln!(output, "    \"\"\"Pattern struct for repeated tree structure.\"\"\"").unwrap();
+        writeln!(output, "    ").unwrap();
+        writeln!(output, "    def __init__(self, client: BrkClientBase, base_path: str):").unwrap();
+
+        for field in &pattern.fields {
+            let py_type = field_to_python_type(field, metadata);
+            if metadata.is_pattern_type(&field.rust_type) {
+                writeln!(
+                    output,
+                    "        self.{}: {} = {}(client, f'{{base_path}}/{}')",
+                    to_snake_case(&field.name), py_type, field.rust_type, field.name
+                ).unwrap();
+            } else if field_uses_accessor(field, metadata) {
+                let accessor = metadata.find_index_set_pattern(&field.indexes).unwrap();
+                writeln!(
+                    output,
+                    "        self.{}: {} = {}(client, f'{{base_path}}/{}')",
+                    to_snake_case(&field.name), py_type, accessor.name, field.name
+                ).unwrap();
+            } else {
+                writeln!(
+                    output,
+                    "        self.{}: {} = MetricNode(client, f'{{base_path}}/{}')",
+                    to_snake_case(&field.name), py_type, field.name
+                ).unwrap();
+            }
+        }
+
+        writeln!(output).unwrap();
+    }
+}
+
+/// Convert pattern field to Python type annotation
+fn field_to_python_type(field: &PatternField, metadata: &ClientMetadata) -> String {
+    if metadata.is_pattern_type(&field.rust_type) {
+        // Pattern type - use pattern name directly
+        field.rust_type.clone()
+    } else if let Some(accessor) = metadata.find_index_set_pattern(&field.indexes) {
+        // Leaf with a reusable accessor pattern
+        let py_type = json_type_to_python(&field.json_type);
+        format!("{}[{}]", accessor.name, py_type)
+    } else {
+        // Leaf with unique index set - use MetricNode directly
+        let py_type = json_type_to_python(&field.json_type);
+        format!("MetricNode[{}]", py_type)
+    }
+}
+
+/// Check if a field should use an index accessor
+fn field_uses_accessor(field: &PatternField, metadata: &ClientMetadata) -> bool {
+    metadata.find_index_set_pattern(&field.indexes).is_some()
+}
+
+/// Convert JSON Schema type to Python type
+fn json_type_to_python(json_type: &str) -> &str {
+    match json_type {
+        "integer" => "int",
+        "number" => "float",
+        "boolean" => "bool",
+        "string" => "str",
+        "array" => "List",
+        "object" => "dict",
+        _ => "Any",
+    }
+}
+
+/// Generate tree classes
+fn generate_tree_classes(
+    output: &mut String,
+    catalog: &TreeNode,
+    metadata: &ClientMetadata,
+) {
+    writeln!(output, "# Catalog tree classes\n").unwrap();
+
+    let pattern_lookup = metadata.pattern_lookup();
+    let mut generated = HashSet::new();
+    generate_tree_class(output, "CatalogTree", catalog, &pattern_lookup, metadata, &mut generated);
+}
+
+/// Recursively generate tree classes
+fn generate_tree_class(
+    output: &mut String,
+    name: &str,
+    node: &TreeNode,
+    pattern_lookup: &std::collections::HashMap<Vec<PatternField>, String>,
+    metadata: &ClientMetadata,
+    generated: &mut HashSet<String>,
+) {
+    if let TreeNode::Branch(children) = node {
+        // Build signature
+        let fields = get_node_fields(children, pattern_lookup);
+
+        // Skip if this matches a pattern (already generated)
+        if pattern_lookup.contains_key(&fields) && pattern_lookup.get(&fields) != Some(&name.to_string()) {
+            return;
+        }
+
+        if generated.contains(name) {
+            return;
+        }
+        generated.insert(name.to_string());
+
+        writeln!(output, "class {}:", name).unwrap();
+        writeln!(output, "    \"\"\"Catalog tree node.\"\"\"").unwrap();
+        writeln!(output, "    ").unwrap();
+        writeln!(output, "    def __init__(self, client: BrkClientBase, base_path: str = ''):").unwrap();
+
+        for field in &fields {
+            let py_type = field_to_python_type(field, metadata);
+            if metadata.is_pattern_type(&field.rust_type) {
+                writeln!(
+                    output,
+                    "        self.{}: {} = {}(client, f'{{base_path}}/{}')",
+                    to_snake_case(&field.name), py_type, field.rust_type, field.name
+                ).unwrap();
+            } else if field_uses_accessor(field, metadata) {
+                let accessor = metadata.find_index_set_pattern(&field.indexes).unwrap();
+                writeln!(
+                    output,
+                    "        self.{}: {} = {}(client, f'{{base_path}}/{}')",
+                    to_snake_case(&field.name), py_type, accessor.name, field.name
+                ).unwrap();
+            } else {
+                writeln!(
+                    output,
+                    "        self.{}: {} = MetricNode(client, f'{{base_path}}/{}')",
+                    to_snake_case(&field.name), py_type, field.name
+                ).unwrap();
+            }
+        }
+
+        writeln!(output).unwrap();
+
+        // Generate child classes
+        for (child_name, child_node) in children {
+            if let TreeNode::Branch(grandchildren) = child_node {
+                let child_fields = get_node_fields(grandchildren, pattern_lookup);
+                if !pattern_lookup.contains_key(&child_fields) {
+                    let child_class_name = format!("{}_{}", name, to_pascal_case(child_name));
+                    generate_tree_class(output, &child_class_name, child_node, pattern_lookup, metadata, generated);
+                }
+            }
+        }
+    }
+}
+
+/// Generate the main client class
+fn generate_main_client(output: &mut String, endpoints: &[Endpoint]) {
+    writeln!(output, "class BrkClient(BrkClientBase):").unwrap();
+    writeln!(output, "    \"\"\"Main BRK client with catalog tree and API methods.\"\"\"").unwrap();
+    writeln!(output, "    ").unwrap();
+    writeln!(output, "    def __init__(self, base_url: str = 'http://localhost:3000', timeout: float = 30.0):").unwrap();
+    writeln!(output, "        super().__init__(base_url, timeout)").unwrap();
+    writeln!(output, "        self.tree = CatalogTree(self)").unwrap();
+    writeln!(output).unwrap();
+
+    // Generate API methods
+    generate_api_methods(output, endpoints);
+}
+
+/// Generate API methods from OpenAPI endpoints
+fn generate_api_methods(output: &mut String, endpoints: &[Endpoint]) {
+    for endpoint in endpoints {
+        if endpoint.method != "GET" {
+            continue;
+        }
+
+        let method_name = endpoint_to_method_name(endpoint);
+        let return_type = endpoint.response_type.as_deref().unwrap_or("Any");
+
+        // Build method signature
+        let params = build_method_params(endpoint);
+        writeln!(output, "    def {}(self{}) -> {}:", method_name, params, return_type).unwrap();
+
+        // Docstring
+        if let Some(summary) = &endpoint.summary {
+            writeln!(output, "        \"\"\"{}\"\"\"", summary).unwrap();
+        }
+
+        // Build path
+        let path = build_path_template(&endpoint.path, &endpoint.path_params);
+
+        if endpoint.query_params.is_empty() {
+            writeln!(output, "        return self.get(f'{}')", path).unwrap();
+        } else {
+            writeln!(output, "        params = []").unwrap();
+            for param in &endpoint.query_params {
+                if param.required {
+                    writeln!(output, "        params.append(f'{}={{{}}}')", param.name, param.name).unwrap();
+                } else {
+                    writeln!(output, "        if {} is not None: params.append(f'{}={{{}}}')", param.name, param.name, param.name).unwrap();
+                }
+            }
+            writeln!(output, "        query = '&'.join(params)").unwrap();
+            writeln!(output, "        return self.get(f'{}{{\"?\" + query if query else \"\"}}')", path).unwrap();
+        }
+
+        writeln!(output).unwrap();
+    }
+}
+
+fn endpoint_to_method_name(endpoint: &Endpoint) -> String {
+    if let Some(op_id) = &endpoint.operation_id {
+        return to_snake_case(op_id);
+    }
+    let parts: Vec<&str> = endpoint.path.split('/').filter(|s| !s.is_empty() && !s.starts_with('{')).collect();
+    format!("get_{}", parts.join("_"))
+}
+
+fn build_method_params(endpoint: &Endpoint) -> String {
+    let mut params = Vec::new();
+    for param in &endpoint.path_params {
+        params.push(format!(", {}: str", param.name));
+    }
+    for param in &endpoint.query_params {
+        if param.required {
+            params.push(format!(", {}: str", param.name));
+        } else {
+            params.push(format!(", {}: Optional[str] = None", param.name));
+        }
+    }
+    params.join("")
+}
+
+fn build_path_template(path: &str, path_params: &[super::Parameter]) -> String {
+    let mut result = path.to_string();
+    for param in path_params {
+        let placeholder = format!("{{{}}}", param.name);
+        let interpolation = format!("{{{{{}}}}}", param.name);
+        result = result.replace(&placeholder, &interpolation);
+    }
+    result
+}
+
+/// Convert JSON Schema to Python type hint
+pub fn schema_to_python_type(schema: &serde_json::Value) -> String {
+    if let Some(ty) = schema.get("type").and_then(|v| v.as_str()) {
+        match ty {
+            "null" => "None".to_string(),
+            "boolean" => "bool".to_string(),
+            "integer" => "int".to_string(),
+            "number" => "float".to_string(),
+            "string" => "str".to_string(),
+            "array" => {
+                if let Some(items) = schema.get("items") {
+                    format!("List[{}]", schema_to_python_type(items))
+                } else {
+                    "List[Any]".to_string()
+                }
+            }
+            "object" => "dict[str, Any]".to_string(),
+            _ => "Any".to_string(),
+        }
+    } else if schema.get("anyOf").is_some() || schema.get("oneOf").is_some() {
+        "Any".to_string()
+    } else if let Some(reference) = schema.get("$ref").and_then(|v| v.as_str()) {
+        reference.rsplit('/').next().unwrap_or("Any").to_string()
+    } else {
+        "Any".to_string()
+    }
+}
+

crates/brk_binder/src/generator/rust.rs

@@ -1,10 +1,533 @@
+use std::collections::HashSet;
+use std::fmt::Write as FmtWrite;
+use std::fs;
 use std::io;
 use std::path::Path;
 
-use super::ClientMetadata;
+use brk_types::{Index, TreeNode};
+
+use super::{ClientMetadata, Endpoint, IndexSetPattern, PatternField, StructuralPattern, get_node_fields, to_pascal_case, to_snake_case};
+
+/// Generate Rust client from metadata and OpenAPI endpoints
+pub fn generate_rust_client(
+    metadata: &ClientMetadata,
+    endpoints: &[Endpoint],
+    output_dir: &Path,
+) -> io::Result<()> {
+    let mut output = String::new();
+
+    // Header
+    writeln!(output, "// Auto-generated BRK Rust client").unwrap();
+    writeln!(output, "// Do not edit manually\n").unwrap();
+    writeln!(output, "#![allow(non_camel_case_types)]").unwrap();
+    writeln!(output, "#![allow(dead_code)]\n").unwrap();
+
+    // Imports
+    generate_imports(&mut output);
+
+    // Generate base client
+    generate_base_client(&mut output);
+
+    // Generate MetricNode
+    generate_metric_node(&mut output);
+
+    // Generate index accessor structs (for each unique set of indexes)
+    generate_index_accessors(&mut output, &metadata.index_set_patterns);
+
+    // Generate pattern structs (reusable, appearing 2+ times)
+    generate_pattern_structs(&mut output, &metadata.structural_patterns, metadata);
+
+    // Generate tree - each node uses its pattern or is generated inline
+    generate_tree(&mut output, &metadata.catalog, metadata);
+
+    // Generate main client with API methods
+    generate_main_client(&mut output, endpoints);
+
+    fs::write(output_dir.join("client.rs"), output)?;
 
-/// Generate Rust client from metadata
-pub fn generate_rust_client(_metadata: &ClientMetadata, _output_dir: &Path) -> io::Result<()> {
-    // TODO: Implement Rust client generation
     Ok(())
 }
+
+fn generate_imports(output: &mut String) {
+    writeln!(
+        output,
+        r#"use std::marker::PhantomData;
+use serde::de::DeserializeOwned;
+use brk_types::*;
+
+"#
+    )
+    .unwrap();
+}
+
+fn generate_base_client(output: &mut String) {
+    writeln!(
+        output,
+        r#"/// Error type for BRK client operations.
+#[derive(Debug)]
+pub struct BrkError {{
+    pub message: String,
+}}
+
+impl std::fmt::Display for BrkError {{
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {{
+        write!(f, "{{}}", self.message)
+    }}
+}}
+
+impl std::error::Error for BrkError {{}}
+
+/// Result type for BRK client operations.
+pub type Result<T> = std::result::Result<T, BrkError>;
+
+/// Options for configuring the BRK client.
+#[derive(Debug, Clone)]
+pub struct BrkClientOptions {{
+    pub base_url: String,
+    pub timeout_ms: u64,
+}}
+
+impl Default for BrkClientOptions {{
+    fn default() -> Self {{
+        Self {{
+            base_url: "http://localhost:3000".to_string(),
+            timeout_ms: 30000,
+        }}
+    }}
+}}
+
+/// Base HTTP client for making requests.
+#[derive(Debug, Clone)]
+pub struct BrkClientBase {{
+    base_url: String,
+    client: reqwest::blocking::Client,
+}}
+
+impl BrkClientBase {{
+    /// Create a new client with the given base URL.
+    pub fn new(base_url: impl Into<String>) -> Result<Self> {{
+        let base_url = base_url.into();
+        let client = reqwest::blocking::Client::new();
+        Ok(Self {{ base_url, client }})
+    }}
+
+    /// Create a new client with options.
+    pub fn with_options(options: BrkClientOptions) -> Result<Self> {{
+        let client = reqwest::blocking::Client::builder()
+            .timeout(std::time::Duration::from_millis(options.timeout_ms))
+            .build()
+            .map_err(|e| BrkError {{ message: e.to_string() }})?;
+        Ok(Self {{
+            base_url: options.base_url,
+            client,
+        }})
+    }}
+
+    /// Make a GET request.
+    pub fn get<T: DeserializeOwned>(&self, path: &str) -> Result<T> {{
+        let url = format!("{{}}{{}}", self.base_url, path);
+        self.client
+            .get(&url)
+            .send()
+            .map_err(|e| BrkError {{ message: e.to_string() }})?
+            .json()
+            .map_err(|e| BrkError {{ message: e.to_string() }})
+    }}
+}}
+
+"#
+    )
+    .unwrap();
+}
+
+fn generate_metric_node(output: &mut String) {
+    writeln!(
+        output,
+        r#"/// A metric node that can fetch data for different indexes.
+pub struct MetricNode<'a, T> {{
+    client: &'a BrkClientBase,
+    path: String,
+    _marker: PhantomData<T>,
+}}
+
+impl<'a, T: DeserializeOwned> MetricNode<'a, T> {{
+    pub fn new(client: &'a BrkClientBase, path: String) -> Self {{
+        Self {{
+            client,
+            path,
+            _marker: PhantomData,
+        }}
+    }}
+
+    /// Fetch all data points for this metric.
+    pub fn get(&self) -> Result<Vec<T>> {{
+        self.client.get(&self.path)
+    }}
+
+    /// Fetch data points within a date range.
+    pub fn get_range(&self, from: &str, to: &str) -> Result<Vec<T>> {{
+        let path = format!("{{}}?from={{}}&to={{}}", self.path, from, to);
+        self.client.get(&path)
+    }}
+}}
+
+"#
+    )
+    .unwrap();
+}
+
+/// Generate index accessor structs for each unique set of indexes
+fn generate_index_accessors(output: &mut String, patterns: &[IndexSetPattern]) {
+    if patterns.is_empty() {
+        return;
+    }
+
+    writeln!(output, "// Index accessor structs\n").unwrap();
+
+    for pattern in patterns {
+        writeln!(output, "/// Index accessor for metrics with {} indexes.", pattern.indexes.len()).unwrap();
+        writeln!(output, "pub struct {}<'a, T> {{", pattern.name).unwrap();
+
+        for index in &pattern.indexes {
+            let field_name = index_to_field_name(index);
+            writeln!(output, "    pub {}: MetricNode<'a, T>,", field_name).unwrap();
+        }
+
+        writeln!(output, "    _marker: PhantomData<T>,").unwrap();
+        writeln!(output, "}}\n").unwrap();
+
+        // Generate impl block with constructor
+        writeln!(output, "impl<'a, T: DeserializeOwned> {}<'a, T> {{", pattern.name).unwrap();
+        writeln!(output, "    pub fn new(client: &'a BrkClientBase, base_path: &str) -> Self {{").unwrap();
+        writeln!(output, "        Self {{").unwrap();
+
+        for index in &pattern.indexes {
+            let field_name = index_to_field_name(index);
+            let path_segment = index.serialize_short();
+            writeln!(
+                output,
+                "            {}: MetricNode::new(client, format!(\"{{base_path}}/{}\")),",
+                field_name, path_segment
+            ).unwrap();
+        }
+
+        writeln!(output, "            _marker: PhantomData,").unwrap();
+        writeln!(output, "        }}").unwrap();
+        writeln!(output, "    }}").unwrap();
+        writeln!(output, "}}\n").unwrap();
+    }
+}
+
+/// Convert an Index to a snake_case field name (e.g., DateIndex -> by_date)
+fn index_to_field_name(index: &Index) -> String {
+    let short = index.serialize_short();
+    format!("by_{}", to_snake_case(short))
+}
+
+/// Generate pattern structs (those appearing 2+ times)
+fn generate_pattern_structs(output: &mut String, patterns: &[StructuralPattern], metadata: &ClientMetadata) {
+    if patterns.is_empty() {
+        return;
+    }
+
+    writeln!(output, "// Reusable pattern structs\n").unwrap();
+
+    for pattern in patterns {
+        writeln!(output, "/// Pattern struct for repeated tree structure.").unwrap();
+        writeln!(output, "pub struct {}<'a> {{", pattern.name).unwrap();
+
+        for field in &pattern.fields {
+            let field_name = to_snake_case(&field.name);
+            let type_annotation = field_to_type_annotation(field, metadata);
+            writeln!(output, "    pub {}: {},", field_name, type_annotation).unwrap();
+        }
+
+        writeln!(output, "}}\n").unwrap();
+
+        // Generate impl block with constructor
+        writeln!(output, "impl<'a> {}<'a> {{", pattern.name).unwrap();
+        writeln!(output, "    pub fn new(client: &'a BrkClientBase, base_path: &str) -> Self {{").unwrap();
+        writeln!(output, "        Self {{").unwrap();
+
+        for field in &pattern.fields {
+            let field_name = to_snake_case(&field.name);
+            if metadata.is_pattern_type(&field.rust_type) {
+                writeln!(
+                    output,
+                    "            {}: {}::new(client, &format!(\"{{base_path}}/{}\"))," ,
+                    field_name, field.rust_type, field.name
+                ).unwrap();
+            } else if field_uses_accessor(field, metadata) {
+                let accessor = metadata.find_index_set_pattern(&field.indexes).unwrap();
+                writeln!(
+                    output,
+                    "            {}: {}::new(client, &format!(\"{{base_path}}/{}\"))," ,
+                    field_name, accessor.name, field.name
+                ).unwrap();
+            } else {
+                writeln!(
+                    output,
+                    "            {}: MetricNode::new(client, format!(\"{{base_path}}/{}\"))," ,
+                    field_name, field.name
+                ).unwrap();
+            }
+        }
+
+        writeln!(output, "        }}").unwrap();
+        writeln!(output, "    }}").unwrap();
+        writeln!(output, "}}\n").unwrap();
+    }
+}
+
+/// Convert a PatternField to the full type annotation
+fn field_to_type_annotation(field: &PatternField, metadata: &ClientMetadata) -> String {
+    if metadata.is_pattern_type(&field.rust_type) {
+        format!("{}<'a>", field.rust_type)
+    } else if let Some(accessor) = metadata.find_index_set_pattern(&field.indexes) {
+        // Leaf with a reusable accessor pattern
+        format!("{}<'a, {}>", accessor.name, field.rust_type)
+    } else {
+        // Leaf with unique index set - use MetricNode directly
+        format!("MetricNode<'a, {}>", field.rust_type)
+    }
+}
+
+/// Check if a field should use an index accessor
+fn field_uses_accessor(field: &PatternField, metadata: &ClientMetadata) -> bool {
+    metadata.find_index_set_pattern(&field.indexes).is_some()
+}
+
+/// Generate the catalog tree structure
+fn generate_tree(
+    output: &mut String,
+    catalog: &TreeNode,
+    metadata: &ClientMetadata,
+) {
+    writeln!(output, "// Catalog tree\n").unwrap();
+
+    let pattern_lookup = metadata.pattern_lookup();
+    let mut generated = HashSet::new();
+    generate_tree_node(output, "CatalogTree", catalog, &pattern_lookup, metadata, &mut generated);
+}
+
+/// Recursively generate tree nodes
+fn generate_tree_node(
+    output: &mut String,
+    name: &str,
+    node: &TreeNode,
+    pattern_lookup: &std::collections::HashMap<Vec<PatternField>, String>,
+    metadata: &ClientMetadata,
+    generated: &mut HashSet<String>,
+) {
+    if let TreeNode::Branch(children) = node {
+        // Build the signature for this node
+        let mut fields: Vec<PatternField> = children
+            .iter()
+            .map(|(child_name, child_node)| {
+                let (rust_type, json_type, indexes) = match child_node {
+                    TreeNode::Leaf(leaf) => (
+                        leaf.value_type().to_string(),
+                        leaf.schema.get("type").and_then(|v| v.as_str()).unwrap_or("object").to_string(),
+                        leaf.indexes().clone(),
+                    ),
+                    TreeNode::Branch(grandchildren) => {
+                        // Get pattern name for this child
+                        let child_fields = get_node_fields(grandchildren, pattern_lookup);
+                        let pattern_name = pattern_lookup
+                            .get(&child_fields)
+                            .cloned()
+                            .unwrap_or_else(|| format!("{}_{}", name, to_pascal_case(child_name)));
+                        (pattern_name.clone(), pattern_name, std::collections::BTreeSet::new())
+                    }
+                };
+                PatternField {
+                    name: child_name.clone(),
+                    rust_type,
+                    json_type,
+                    indexes,
+                }
+            })
+            .collect();
+        fields.sort_by(|a, b| a.name.cmp(&b.name));
+
+        // Check if this matches a reusable pattern
+        if let Some(pattern_name) = pattern_lookup.get(&fields) {
+            // This node matches a pattern that will be generated separately
+            // Don't generate it here, it's already in pattern_structs
+            if pattern_name != name {
+                return;
+            }
+        }
+
+        // Generate this struct if not already generated
+        if generated.contains(name) {
+            return;
+        }
+        generated.insert(name.to_string());
+
+        writeln!(output, "/// Catalog tree node.").unwrap();
+        writeln!(output, "pub struct {}<'a> {{", name).unwrap();
+
+        for field in &fields {
+            let field_name = to_snake_case(&field.name);
+            let type_annotation = field_to_type_annotation(field, metadata);
+            writeln!(output, "    pub {}: {},", field_name, type_annotation).unwrap();
+        }
+
+        writeln!(output, "}}\n").unwrap();
+
+        // Generate impl block
+        writeln!(output, "impl<'a> {}<'a> {{", name).unwrap();
+        writeln!(output, "    pub fn new(client: &'a BrkClientBase, base_path: &str) -> Self {{").unwrap();
+        writeln!(output, "        Self {{").unwrap();
+
+        for field in &fields {
+            let field_name = to_snake_case(&field.name);
+            if metadata.is_pattern_type(&field.rust_type) {
+                writeln!(
+                    output,
+                    "            {}: {}::new(client, &format!(\"{{base_path}}/{}\"))," ,
+                    field_name, field.rust_type, field.name
+                ).unwrap();
+            } else if field_uses_accessor(field, metadata) {
+                let accessor = metadata.find_index_set_pattern(&field.indexes).unwrap();
+                writeln!(
+                    output,
+                    "            {}: {}::new(client, &format!(\"{{base_path}}/{}\"))," ,
+                    field_name, accessor.name, field.name
+                ).unwrap();
+            } else {
+                writeln!(
+                    output,
+                    "            {}: MetricNode::new(client, format!(\"{{base_path}}/{}\"))," ,
+                    field_name, field.name
+                ).unwrap();
+            }
+        }
+
+        writeln!(output, "        }}").unwrap();
+        writeln!(output, "    }}").unwrap();
+        writeln!(output, "}}\n").unwrap();
+
+        // Recursively generate child nodes that aren't patterns
+        for (child_name, child_node) in children {
+            if let TreeNode::Branch(grandchildren) = child_node {
+                let child_fields = get_node_fields(grandchildren, pattern_lookup);
+                if !pattern_lookup.contains_key(&child_fields) {
+                    let child_struct_name = format!("{}_{}", name, to_pascal_case(child_name));
+                    generate_tree_node(output, &child_struct_name, child_node, pattern_lookup, metadata, generated);
+                }
+            }
+        }
+    }
+}
+
+/// Generate the main client struct
+fn generate_main_client(output: &mut String, endpoints: &[Endpoint]) {
+    writeln!(
+        output,
+        r#"/// Main BRK client with catalog tree and API methods.
+pub struct BrkClient {{
+    base: BrkClientBase,
+}}
+
+impl BrkClient {{
+    /// Create a new client with the given base URL.
+    pub fn new(base_url: impl Into<String>) -> Result<Self> {{
+        Ok(Self {{
+            base: BrkClientBase::new(base_url)?,
+        }})
+    }}
+
+    /// Create a new client with options.
+    pub fn with_options(options: BrkClientOptions) -> Result<Self> {{
+        Ok(Self {{
+            base: BrkClientBase::with_options(options)?,
+        }})
+    }}
+
+    /// Get the catalog tree for navigating metrics.
+    pub fn tree(&self) -> CatalogTree<'_> {{
+        CatalogTree::new(&self.base, "")
+    }}
+"#
+    )
+    .unwrap();
+
+    // Generate API methods
+    generate_api_methods(output, endpoints);
+
+    writeln!(output, "}}").unwrap();
+}
+
+/// Generate API methods from OpenAPI endpoints
+fn generate_api_methods(output: &mut String, endpoints: &[Endpoint]) {
+    for endpoint in endpoints {
+        if endpoint.method != "GET" {
+            continue;
+        }
+
+        let method_name = endpoint_to_method_name(endpoint);
+        let return_type = endpoint.response_type.as_deref().unwrap_or("serde_json::Value");
+
+        // Build doc comment
+        writeln!(output, "    /// {}", endpoint.summary.as_deref().unwrap_or(&method_name)).unwrap();
+
+        // Build method signature
+        let params = build_method_params(endpoint);
+        writeln!(output, "    pub fn {}(&self{}) -> Result<{}> {{", method_name, params, return_type).unwrap();
+
+        // Build path
+        let path = build_path_template(&endpoint.path, &endpoint.path_params);
+
+        if endpoint.query_params.is_empty() {
+            writeln!(output, "        self.base.get(&format!(\"{}\"))", path).unwrap();
+        } else {
+            writeln!(output, "        let mut query = Vec::new();").unwrap();
+            for param in &endpoint.query_params {
+                if param.required {
+                    writeln!(output, "        query.push(format!(\"{}={{}}\", {}));", param.name, param.name).unwrap();
+                } else {
+                    writeln!(output, "        if let Some(v) = {} {{ query.push(format!(\"{}={{}}\", v)); }}", param.name, param.name).unwrap();
+                }
+            }
+            writeln!(output, "        let query_str = if query.is_empty() {{ String::new() }} else {{ format!(\"?{{}}\", query.join(\"&\")) }};").unwrap();
+            writeln!(output, "        self.base.get(&format!(\"{}{{}}\", query_str))", path).unwrap();
+        }
+
+        writeln!(output, "    }}\n").unwrap();
+    }
+}
+
+fn endpoint_to_method_name(endpoint: &Endpoint) -> String {
+    if let Some(op_id) = &endpoint.operation_id {
+        return to_snake_case(op_id);
+    }
+    let parts: Vec<&str> = endpoint.path.split('/').filter(|s| !s.is_empty() && !s.starts_with('{')).collect();
+    format!("get_{}", parts.join("_"))
+}
+
+fn build_method_params(endpoint: &Endpoint) -> String {
+    let mut params = Vec::new();
+    for param in &endpoint.path_params {
+        params.push(format!(", {}: &str", param.name));
+    }
+    for param in &endpoint.query_params {
+        if param.required {
+            params.push(format!(", {}: &str", param.name));
+        } else {
+            params.push(format!(", {}: Option<&str>", param.name));
+        }
+    }
+    params.join("")
+}
+
+fn build_path_template(path: &str, path_params: &[super::Parameter]) -> String {
+    let mut result = path.to_string();
+    for param in path_params {
+        let placeholder = format!("{{{}}}", param.name);
+        let interpolation = format!("{{{}}}", param.name);
+        result = result.replace(&placeholder, &interpolation);
+    }
+    result
+}

crates/brk_binder/src/generator/types.rs

@@ -1,4 +1,5 @@
-use std::collections::{BTreeMap, BTreeSet};
+use std::collections::{BTreeSet, HashMap};
+use std::hash::{Hash, Hasher};
 
 use brk_query::Vecs;
 use brk_types::{Index, TreeNode};
@@ -6,94 +7,236 @@ use brk_types::{Index, TreeNode};
 /// Metadata extracted from brk_query for client generation
 #[derive(Debug)]
 pub struct ClientMetadata {
-    /// All metrics with their available indexes and value type
-    pub metrics: BTreeMap<String, MetricInfo>,
     /// The catalog tree structure (with schemas in leaves)
     pub catalog: TreeNode,
-    /// Discovered patterns (sets of indexes that appear together frequently)
+    /// Structural patterns - tree node shapes that repeat
-    pub patterns: Vec<IndexPattern>,
+    pub structural_patterns: Vec<StructuralPattern>,
+    /// All indexes used across the catalog
+    pub used_indexes: BTreeSet<Index>,
+    /// Index set patterns - sets of indexes that appear together on metrics
+    pub index_set_patterns: Vec<IndexSetPattern>,
 }
 
-/// Information about a single metric
+/// A pattern of indexes that appear together on multiple metrics
 #[derive(Debug, Clone)]
-pub struct MetricInfo {
+pub struct IndexSetPattern {
-    /// Metric name (e.g., "difficulty", "supply_total")
+    /// Pattern name (e.g., "DateHeightIndexes")
     pub name: String,
-    /// Available indexes for this metric
+    /// The set of indexes
     pub indexes: BTreeSet<Index>,
-    /// Value type name (e.g., "Sats", "StoredF64")
-    pub value_type: String,
 }
 
-/// A pattern of indexes that appears multiple times across metrics
+/// A structural pattern - a branch structure that appears multiple times in the tree
 #[derive(Debug, Clone)]
-pub struct IndexPattern {
+pub struct StructuralPattern {
-    /// Unique identifier for this pattern
+    /// Pattern name - sanitized for all languages (e.g., "BaseCumulativeSum")
-    pub id: usize,
+    pub name: String,
-    /// The set of indexes in this pattern
+    /// Ordered list of child fields (sorted by field name)
-    pub indexes: BTreeSet<Index>,
+    pub fields: Vec<PatternField>,
-    /// How many metrics use this exact pattern
-    pub usage_count: usize,
 }
 
+/// A field in a structural pattern
+#[derive(Debug, Clone, PartialOrd, Ord)]
+pub struct PatternField {
+    /// Field name
+    pub name: String,
+    /// Rust type: brk_types type for leaves ("Sats", "StoredF64") or pattern name for branches
+    pub rust_type: String,
+    /// JSON type from schema: "integer", "number", "string", "boolean", or pattern name for branches
+    pub json_type: String,
+    /// For leaves: the set of supported indexes. Empty for branches.
+    pub indexes: BTreeSet<Index>,
+}
+
+// Manual implementations of Hash/Eq/PartialEq that exclude `indexes`
+// since indexes aren't part of the structural pattern identity
+impl Hash for PatternField {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.name.hash(state);
+        self.rust_type.hash(state);
+        self.json_type.hash(state);
+        // indexes excluded from hash
+    }
+}
+
+impl PartialEq for PatternField {
+    fn eq(&self, other: &Self) -> bool {
+        self.name == other.name
+            && self.rust_type == other.rust_type
+            && self.json_type == other.json_type
+        // indexes excluded from equality
+    }
+}
+
+impl Eq for PatternField {}
+
+
 impl ClientMetadata {
     /// Extract metadata from brk_query::Vecs
     pub fn from_vecs(vecs: &Vecs) -> Self {
-        let mut metrics = BTreeMap::new();
+        let catalog = vecs.catalog().clone();
-        let mut pattern_counts: BTreeMap<BTreeSet<Index>, usize> = BTreeMap::new();
+        let structural_patterns = detect_structural_patterns(&catalog);
-
+        let (used_indexes, index_set_patterns) = detect_index_patterns(&catalog);
-        // Extract metric information
-        for (name, index_to_vec) in &vecs.metric_to_index_to_vec {
-            let indexes: BTreeSet<Index> = index_to_vec.keys().copied().collect();
-
-            // Get value type from the first available vec
-            let value_type = index_to_vec
-                .values()
-                .next()
-                .map(|v| v.value_type_to_string().to_string())
-                .unwrap_or_else(|| "unknown".to_string());
-
-            // Count pattern usage
-            *pattern_counts.entry(indexes.clone()).or_insert(0) += 1;
-
-            metrics.insert(
-                name.to_string(),
-                MetricInfo {
-                    name: name.to_string(),
-                    indexes,
-                    value_type,
-                },
-            );
-        }
-
-        // Extract patterns that are used by multiple metrics
-        let mut patterns: Vec<IndexPattern> = pattern_counts
-            .into_iter()
-            .filter(|(_, count)| *count >= 2) // Only patterns used by 2+ metrics
-            .enumerate()
-            .map(|(id, (indexes, usage_count))| IndexPattern {
-                id,
-                indexes,
-                usage_count,
-            })
-            .collect();
-
-        // Sort by usage count descending
-        patterns.sort_by(|a, b| b.usage_count.cmp(&a.usage_count));
 
         ClientMetadata {
-            metrics,
+            catalog,
-            catalog: vecs.catalog().clone(),
+            structural_patterns,
-            patterns,
+            used_indexes,
+            index_set_patterns,
         }
     }
 
-    /// Find the pattern that matches a metric's indexes, if any
+    /// Check if an index set matches a pattern
-    pub fn find_pattern_for_metric(&self, metric: &MetricInfo) -> Option<&IndexPattern> {
+    pub fn find_index_set_pattern(&self, indexes: &BTreeSet<Index>) -> Option<&IndexSetPattern> {
-        self.patterns
+        self.index_set_patterns.iter().find(|p| &p.indexes == indexes)
-            .iter()
-            .find(|p| p.indexes == metric.indexes)
     }
+
+    /// Check if a type is a pattern (vs a primitive leaf type)
+    pub fn is_pattern_type(&self, type_name: &str) -> bool {
+        self.structural_patterns.iter().any(|p| p.name == type_name)
+    }
+
+    /// Build a lookup map from field signatures to pattern names
+    pub fn pattern_lookup(&self) -> HashMap<Vec<PatternField>, String> {
+        self.structural_patterns
+            .iter()
+            .map(|p| (p.fields.clone(), p.name.clone()))
+            .collect()
+    }
+}
+
+/// Detect structural patterns in the tree using a bottom-up approach.
+/// For every branch node, create a signature from its children (sorted field names + types).
+/// Patterns that appear 2+ times are deduplicated.
+fn detect_structural_patterns(tree: &TreeNode) -> Vec<StructuralPattern> {
+    // Map from sorted fields signature to pattern name
+    let mut signature_to_pattern: HashMap<Vec<PatternField>, String> = HashMap::new();
+    // Count how many times each signature appears
+    let mut signature_counts: HashMap<Vec<PatternField>, usize> = HashMap::new();
+
+    // Process tree bottom-up to resolve all branch types
+    resolve_branch_patterns(tree, &mut signature_to_pattern, &mut signature_counts);
+
+    // Build final list of patterns (only those appearing 2+ times)
+    let mut patterns: Vec<StructuralPattern> = signature_to_pattern
+        .into_iter()
+        .filter(|(sig, _)| signature_counts.get(sig).copied().unwrap_or(0) >= 2)
+        .map(|(fields, name)| StructuralPattern { name, fields })
+        .collect();
+
+    // Sort by number of fields descending (larger patterns first)
+    patterns.sort_by(|a, b| b.fields.len().cmp(&a.fields.len()));
+
+    patterns
+}
+
+/// Recursively resolve branch patterns bottom-up.
+/// Returns the pattern name for this node if it's a branch, or None if it's a leaf.
+fn resolve_branch_patterns(
+    node: &TreeNode,
+    signature_to_pattern: &mut HashMap<Vec<PatternField>, String>,
+    signature_counts: &mut HashMap<Vec<PatternField>, usize>,
+) -> Option<String> {
+    match node {
+        TreeNode::Leaf(_) => {
+            // Leaves don't have patterns, return None
+            None
+        }
+        TreeNode::Branch(children) => {
+            // First, recursively resolve all children
+            let mut fields: Vec<PatternField> = Vec::new();
+
+            for (child_name, child_node) in children {
+                let (rust_type, json_type, indexes) = match child_node {
+                    TreeNode::Leaf(leaf) => (
+                        leaf.value_type().to_string(),
+                        schema_to_json_type(&leaf.schema),
+                        leaf.indexes().clone(),
+                    ),
+                    TreeNode::Branch(_) => {
+                        // Branch: recursively get its pattern name
+                        let pattern_name = resolve_branch_patterns(child_node, signature_to_pattern, signature_counts)
+                            .unwrap_or_else(|| "Unknown".to_string());
+                        (pattern_name.clone(), pattern_name, BTreeSet::new())
+                    }
+                };
+
+                fields.push(PatternField {
+                    name: child_name.clone(),
+                    rust_type,
+                    json_type,
+                    indexes,
+                });
+            }
+
+            // Sort fields by name for consistent signatures
+            fields.sort_by(|a, b| a.name.cmp(&b.name));
+
+            // Increment count for this signature
+            *signature_counts.entry(fields.clone()).or_insert(0) += 1;
+
+            // Get or create pattern name for this signature
+            let pattern_name = signature_to_pattern
+                .entry(fields.clone())
+                .or_insert_with(|| generate_pattern_name_from_fields(&fields))
+                .clone();
+
+            Some(pattern_name)
+        }
+    }
+}
+
+/// Generate a sanitized pattern name from fields.
+/// Names must be valid identifiers in all target languages (Rust, JS, Python).
+fn generate_pattern_name_from_fields(fields: &[PatternField]) -> String {
+    // Join field names with underscores, then convert to PascalCase
+    let joined: Vec<&str> = fields.iter().map(|f| f.name.as_str()).collect();
+    let raw_name = joined.join("_");
+
+    // Sanitize: ensure it starts with a letter (prepend "P_" if starts with digit)
+    let sanitized = if raw_name.chars().next().map(|c| c.is_ascii_digit()).unwrap_or(false) {
+        format!("P_{}", raw_name)
+    } else {
+        raw_name
+    };
+
+    to_pascal_case(&sanitized)
+}
+
+/// Extract JSON type from JSON Schema
+fn schema_to_json_type(schema: &serde_json::Value) -> String {
+    if let Some(ty) = schema.get("type").and_then(|v| v.as_str()) {
+        ty.to_string()
+    } else {
+        "object".to_string()
+    }
+}
+
+/// Get the field signature for a branch node's children
+pub fn get_node_fields(
+    children: &std::collections::BTreeMap<String, TreeNode>,
+    pattern_lookup: &HashMap<Vec<PatternField>, String>,
+) -> Vec<PatternField> {
+    let mut fields: Vec<PatternField> = children
+        .iter()
+        .map(|(name, node)| {
+            let (rust_type, json_type, indexes) = match node {
+                TreeNode::Leaf(leaf) => (
+                    leaf.value_type().to_string(),
+                    schema_to_json_type(&leaf.schema),
+                    leaf.indexes().clone(),
+                ),
+                TreeNode::Branch(grandchildren) => {
+                    let child_fields = get_node_fields(grandchildren, pattern_lookup);
+                    let pattern_name = pattern_lookup.get(&child_fields).cloned().unwrap_or_else(|| "Unknown".to_string());
+                    (pattern_name.clone(), pattern_name, BTreeSet::new())
+                }
+            };
+            PatternField { name: name.clone(), rust_type, json_type, indexes }
+        })
+        .collect();
+    fields.sort_by(|a, b| a.name.cmp(&b.name));
+    fields
 }
 
 /// Convert a metric name to PascalCase (for struct/class names)
@@ -132,6 +275,73 @@ pub fn to_camel_case(s: &str) -> String {
     }
 }
 
+/// Detect index patterns - collect all indexes and find sets that appear 2+ times
+fn detect_index_patterns(tree: &TreeNode) -> (BTreeSet<Index>, Vec<IndexSetPattern>) {
+    let mut used_indexes: BTreeSet<Index> = BTreeSet::new();
+    let mut index_sets: Vec<BTreeSet<Index>> = Vec::new();
+
+    // Traverse tree and collect index information from leaves
+    collect_indexes_from_tree(tree, &mut used_indexes, &mut index_sets);
+
+    // Count occurrences of each unique index set
+    let mut index_set_counts: Vec<(BTreeSet<Index>, usize)> = Vec::new();
+    for index_set in index_sets {
+        if let Some(entry) = index_set_counts.iter_mut().find(|(s, _)| s == &index_set) {
+            entry.1 += 1;
+        } else {
+            index_set_counts.push((index_set, 1));
+        }
+    }
+
+    // Build patterns for index sets appearing 2+ times
+    let mut patterns: Vec<IndexSetPattern> = index_set_counts
+        .into_iter()
+        .filter(|(indexes, count)| *count >= 2 && !indexes.is_empty())
+        .map(|(indexes, _)| IndexSetPattern {
+            name: generate_index_set_name(&indexes),
+            indexes,
+        })
+        .collect();
+
+    // Sort by number of indexes descending
+    patterns.sort_by(|a, b| b.indexes.len().cmp(&a.indexes.len()));
+
+    (used_indexes, patterns)
+}
+
+/// Recursively collect indexes from tree leaves
+fn collect_indexes_from_tree(
+    node: &TreeNode,
+    used_indexes: &mut BTreeSet<Index>,
+    index_sets: &mut Vec<BTreeSet<Index>>,
+) {
+    match node {
+        TreeNode::Leaf(leaf) => {
+            // Add all indexes from this leaf to the global set
+            used_indexes.extend(leaf.indexes().iter().cloned());
+            // Collect this index set
+            index_sets.push(leaf.indexes().clone());
+        }
+        TreeNode::Branch(children) => {
+            for (_, child) in children {
+                collect_indexes_from_tree(child, used_indexes, index_sets);
+            }
+        }
+    }
+}
+
+/// Generate a name for an index set pattern
+fn generate_index_set_name(indexes: &BTreeSet<Index>) -> String {
+    if indexes.len() == 1 {
+        let index = indexes.iter().next().unwrap();
+        return format!("{}Accessor", to_pascal_case(index.serialize_short()));
+    }
+
+    // For multiple indexes, create a descriptive name
+    let names: Vec<&str> = indexes.iter().map(|i| i.serialize_short()).collect();
+    format!("{}Accessor", to_pascal_case(&names.join("_")))
+}
+
 /// Convert a serde_json::Value (JSON Schema) to a JSDoc type annotation
 pub fn schema_to_jsdoc(schema: &serde_json::Value) -> String {
     if let Some(ty) = schema.get("type").and_then(|v| v.as_str()) {

crates/brk_computer/.gitignore

@@ -1 +1,2 @@
 bottlenecks.md
+BUG.md

crates/brk_computer/src/stateful/process/lookup.rs

@@ -34,10 +34,30 @@ impl<'a> AddressLookup<'a> {
 
         match map.entry(type_index) {
             Entry::Occupied(entry) => {
+                // Address is in cache. Need to determine if it's been processed
+                // by process_received (added to a cohort) or just loaded this block.
+                //
+                // - If wrapper is New AND funded_txo_count == 0: hasn't received yet,
+                //   was just created in process_outputs this block → New
+                // - If wrapper is New AND funded_txo_count > 0: received in previous
+                //   block but still in cache (no flush) → Loaded
+                // - If wrapper is FromLoaded/FromEmpty: loaded from storage → use wrapper
                 let source = match entry.get() {
-                    WithAddressDataSource::New(_) => AddressSource::New,
+                    WithAddressDataSource::New(data) => {
+                        if data.funded_txo_count == 0 {
+                            AddressSource::New
+                        } else {
+                            AddressSource::Loaded
+                        }
+                    }
                     WithAddressDataSource::FromLoaded(..) => AddressSource::Loaded,
-                    WithAddressDataSource::FromEmpty(..) => AddressSource::FromEmpty,
+                    WithAddressDataSource::FromEmpty(_, data) => {
+                        if data.utxo_count() == 0 {
+                            AddressSource::FromEmpty
+                        } else {
+                            AddressSource::Loaded
+                        }
+                    }
                 };
                 (entry.into_mut(), source)
             }

crates/brk_computer/src/stateful/process/received.rs

@@ -62,13 +62,30 @@ pub fn process_received(
 
                 if AmountBucket::from(prev_balance) != AmountBucket::from(new_balance) {
                     // Crossing cohort boundary - subtract from old, add to new
-                    cohorts
+                    let cohort_state = cohorts
                         .amount_range
                         .get_mut(prev_balance)
                         .state
                         .as_mut()
-                        .unwrap()
+                        .unwrap();
-                        .subtract(addr_data);
+
+                    // Debug info for tracking down underflow issues
+                    if cohort_state.inner.supply.utxo_count < addr_data.utxo_count() as u64 {
+                        panic!(
+                            "process_received: cohort underflow detected!\n\
+                            output_type={:?}, type_index={:?}\n\
+                            prev_balance={}, new_balance={}, total_value={}\n\
+                            Address: {:?}",
+                            output_type,
+                            type_index,
+                            prev_balance,
+                            new_balance,
+                            total_value,
+                            addr_data
+                        );
+                    }
+
+                    cohort_state.subtract(addr_data);
                     addr_data.receive_outputs(total_value, price, output_count);
                     cohorts
                         .amount_range

crates/brk_computer/src/stateful/process/sent.rs

@@ -8,7 +8,7 @@
 use brk_error::Result;
 use brk_grouper::{ByAddressType, Filtered};
 use brk_types::{CheckedSub, Dollars, Height, Sats, Timestamp, TypeIndex};
-use vecdb::VecIndex;
+use vecdb::{VecIndex, unlikely};
 
 use super::super::address::HeightToAddressTypeToVec;
 use super::super::cohorts::AddressCohorts;
@@ -63,13 +63,36 @@ pub fn process_sent(
 
                 if will_be_empty || filters_differ {
                     // Subtract from old cohort
-                    cohorts
+                    let cohort_state = cohorts
                         .amount_range
                         .get_mut(prev_balance)
                         .state
                         .as_mut()
-                        .unwrap()
+                        .unwrap();
-                        .subtract(addr_data);
+
+                    // Debug info for tracking down underflow issues
+                    if unlikely(
+                        cohort_state.inner.supply.utxo_count < addr_data.utxo_count() as u64,
+                    ) {
+                        panic!(
+                            "process_sent: cohort underflow detected!\n\
+                            Block context: prev_height={:?}, output_type={:?}, type_index={:?}\n\
+                            prev_balance={}, new_balance={}, value={}\n\
+                            will_be_empty={}, filters_differ={}\n\
+                            Address: {:?}",
+                            prev_height,
+                            output_type,
+                            type_index,
+                            prev_balance,
+                            new_balance,
+                            value,
+                            will_be_empty,
+                            filters_differ,
+                            addr_data
+                        );
+                    }
+
+                    cohort_state.subtract(addr_data);
 
                     // Update address data
                     addr_data.send(value, prev_price)?;

crates/brk_computer/src/stateful/states/address_cohort.rs

@@ -2,6 +2,7 @@ use std::path::Path;
 
 use brk_error::Result;
 use brk_types::{Dollars, Height, LoadedAddressData, Sats};
+use vecdb::unlikely;
 
 use crate::stateful::states::{RealizedState, SupplyState};
 
@@ -136,11 +137,46 @@ impl AddressCohortState {
     }
 
     pub fn subtract(&mut self, addressdata: &LoadedAddressData) {
-        self.addr_count = self.addr_count.checked_sub(1).unwrap();
+        let addr_supply: SupplyState = addressdata.into();
+        let realized_price = addressdata.realized_price();
+
+        // Check for potential underflow before it happens
+        if unlikely(self.inner.supply.utxo_count < addr_supply.utxo_count) {
+            panic!(
+                "AddressCohortState::subtract underflow!\n\
+                Cohort state: addr_count={}, supply={}\n\
+                Address being subtracted: {}\n\
+                Address supply: {}\n\
+                Realized price: {}\n\
+                This means the address is not properly tracked in this cohort.",
+                self.addr_count, self.inner.supply, addressdata, addr_supply, realized_price
+            );
+        }
+        if unlikely(self.inner.supply.value < addr_supply.value) {
+            panic!(
+                "AddressCohortState::subtract value underflow!\n\
+                Cohort state: addr_count={}, supply={}\n\
+                Address being subtracted: {}\n\
+                Address supply: {}\n\
+                Realized price: {}\n\
+                This means the address is not properly tracked in this cohort.",
+                self.addr_count, self.inner.supply, addressdata, addr_supply, realized_price
+            );
+        }
+
+        self.addr_count = self.addr_count.checked_sub(1).unwrap_or_else(|| {
+            panic!(
+                "AddressCohortState::subtract addr_count underflow! addr_count=0\n\
+                Address being subtracted: {}\n\
+                Realized price: {}",
+                addressdata, realized_price
+            )
+        });
+
         self.inner.decrement_(
-            &addressdata.into(),
+            &addr_supply,
             addressdata.realized_cap,
-            addressdata.realized_price(),
+            realized_price,
         );
     }
 

crates/brk_computer/src/stateful/states/price_to_amount.rs

@@ -9,7 +9,7 @@ use brk_types::{Dollars, Height, Sats};
 use derive_deref::{Deref, DerefMut};
 use pco::standalone::{simple_decompress, simpler_compress};
 use serde::{Deserialize, Serialize};
-use vecdb::Bytes;
+use vecdb::{Bytes, unlikely};
 
 use crate::{grouped::PERCENTILES_LEN, utils::OptionExt};
 
@@ -87,6 +87,25 @@ impl PriceToAmount {
 
     pub fn decrement(&mut self, price: Dollars, supply_state: &SupplyState) {
         if let Some(amount) = self.state.um().get_mut(&price) {
+            if unlikely(*amount < supply_state.value) {
+                let amount = *amount;
+                panic!(
+                    "PriceToAmount::decrement underflow!\n\
+                    Path: {:?}\n\
+                    Price: {}\n\
+                    Bucket amount: {}\n\
+                    Trying to decrement by: {}\n\
+                    Supply state: utxo_count={}, value={}\n\
+                    All buckets: {:?}",
+                    self.pathbuf,
+                    price,
+                    amount,
+                    supply_state.value,
+                    supply_state.utxo_count,
+                    supply_state.value,
+                    self.state.u().iter().collect::<Vec<_>>()
+                );
+            }
             *amount -= supply_state.value;
             if *amount == Sats::ZERO {
                 self.state.um().remove(&price);
@@ -95,8 +114,18 @@ impl PriceToAmount {
                 buckets.decrement(price, supply_state.value);
             }
         } else {
-            dbg!(price, &self.pathbuf);
+            panic!(
-            unreachable!();
+                "PriceToAmount::decrement price not found!\n\
+                Path: {:?}\n\
+                Price: {}\n\
+                Supply state: utxo_count={}, value={}\n\
+                All buckets: {:?}",
+                self.pathbuf,
+                price,
+                supply_state.utxo_count,
+                supply_state.value,
+                self.state.u().iter().collect::<Vec<_>>()
+            );
         }
     }
 

crates/brk_computer/src/stateful/states/supply.rs

@@ -39,8 +39,22 @@ impl AddAssign<&SupplyState> for SupplyState {
 
 impl SubAssign<&SupplyState> for SupplyState {
     fn sub_assign(&mut self, rhs: &Self) {
-        self.utxo_count = self.utxo_count.checked_sub(rhs.utxo_count).unwrap();
+        self.utxo_count = self.utxo_count.checked_sub(rhs.utxo_count).unwrap_or_else(|| {
-        self.value = self.value.checked_sub(rhs.value).unwrap();
+            panic!(
+                "SupplyState underflow: cohort utxo_count {} < address utxo_count {}. \
+                This indicates a desync between cohort state and address data. \
+                Try deleting the compute cache and restarting fresh.",
+                self.utxo_count, rhs.utxo_count
+            )
+        });
+        self.value = self.value.checked_sub(rhs.value).unwrap_or_else(|| {
+            panic!(
+                "SupplyState underflow: cohort value {} < address value {}. \
+                This indicates a desync between cohort state and address data. \
+                Try deleting the compute cache and restarting fresh.",
+                self.value, rhs.value
+            )
+        });
     }
 }
 

crates/brk_server/Cargo.toml

@@ -11,6 +11,7 @@ build = "build.rs"
 [dependencies]
 aide = { workspace = true }
 axum = { workspace = true }
+brk_binder = { workspace = true }
 brk_computer = { workspace = true }
 brk_error = { workspace = true }
 brk_fetcher = { workspace = true }

crates/brk_server/src/lib.rs

@@ -89,6 +89,7 @@ impl Server {
             .on_failure(())
             .on_eos(());
 
+        let vecs = state.query.inner().vecs();
         let router = ApiRouter::new()
             .add_api_routes()
             .add_mcp_routes(&state.query, mcp)
@@ -133,10 +134,25 @@ impl Server {
         info!("Starting server on port {port}...");
 
         let mut openapi = create_openapi();
+        let router = router.finish_api(&mut openapi);
+
+        let clients_path = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+            .parent()
+            .unwrap()
+            .join("brk_binder")
+            .join("clients");
+        if clients_path.exists() {
+            let openapi_json = serde_json::to_string(&openapi).unwrap();
+            if let Err(e) = brk_binder::generate_clients(vecs, &openapi_json, &clients_path) {
+                error!("Failed to generate clients: {e}");
+            } else {
+                info!("Generated clients at {}", clients_path.display());
+            }
+        }
+
         serve(
             listener,
             router
-                .finish_api(&mut openapi)
                 .layer(Extension(Arc::new(openapi)))
                 .into_make_service(),
         )

crates/brk_types/src/loadedaddressdata.rs

@@ -51,7 +51,13 @@ impl LoadedAddressData {
 
     #[inline]
     pub fn utxo_count(&self) -> u32 {
-        self.funded_txo_count - self.spent_txo_count
+        self.funded_txo_count.checked_sub(self.spent_txo_count).unwrap_or_else(|| {
+            panic!(
+                "LoadedAddressData corruption: spent_txo_count ({}) > funded_txo_count ({}). \
+                Address data: {:?}",
+                self.spent_txo_count, self.funded_txo_count, self
+            )
+        })
     }
 
     #[inline]

crates/brk_types/src/sats.rs

@@ -110,11 +110,9 @@ impl SaturatingAdd for Sats {
 
 impl SubAssign for Sats {
     fn sub_assign(&mut self, rhs: Self) {
-        *self = self.checked_sub(rhs).unwrap();
+        *self = self.checked_sub(rhs).unwrap_or_else(|| {
-        //     .unwrap_or_else(|| {
+            panic!("Sats underflow: {} - {} would be negative", self, rhs);
-        //     dbg!((*self, rhs));
+        });
-        //     unreachable!();
-        // });
     }
 }