diff --git a/plans/build-graph-dashboard.md b/plans/build-graph-dashboard.md
index 4877bc1..0f379ba 100644
--- a/plans/build-graph-dashboard.md
+++ b/plans/build-graph-dashboard.md
@@ -10,7 +10,7 @@
 - Simplicity is absolutely critical here
 - Use mithril
 - Use typescript
-- Rely on client generated from protobuf interface definitions
+- Rely on client generated from OpenAPI interface definitions
 
 ## Minimal Design
 
@@ -166,7 +166,7 @@ Polling-based updates with Page Visibility API integration:
 - Mithril: ~10KB
 - Custom code: ~20KB
 - CSS: ~5KB
-- Protobuf client: ~15KB
+- OpenAPI client: ~15KB
 
 ### Data Flow
 
@@ -198,7 +198,7 @@ npm run typecheck
 This dashboard implementation is broken into 9 incremental, testable chunks:
 
 ### Phase 1: Foundation & Infrastructure
-- **[Chunk 1: TypeScript Client Generation](./webapp_v1/chunk-1-client-generation.md)** - Generate typed client from proto
+- **[Chunk 1: TypeScript Client Generation](./webapp_v1/chunk-1-client-generation.md)** - Generate typed client from OpenAPI spec
 - **[Chunk 2: Hello World App](./webapp_v1/chunk-2-hello-world-app.md)** - Bazel-built TypeScript + Mithril app
 - **[Chunk 3: Routing Framework](./webapp_v1/chunk-3-routing-framework.md)** - Multi-page routing and layout
 
diff --git a/plans/webapp_v1/chunk-1-client-generation.md b/plans/webapp_v1/chunk-1-client-generation.md
index 7b2308d..6554133 100644
--- a/plans/webapp_v1/chunk-1-client-generation.md
+++ b/plans/webapp_v1/chunk-1-client-generation.md
@@ -22,81 +22,95 @@ Generate TypeScript client code from the DataBuild protobuf definitions to provi
 
 ## Technical Approach
 
-### Proto Analysis
-Key messages to generate TypeScript for:
-- `BuildEvent` and related event types
-- `PartitionRef`, `JobLabel`, `GraphLabel`
-- `BuildRequestStatus`, `PartitionStatus`, `JobStatus`
-- `JobGraph`, `Task`, `JobConfig`
-- Service request/response types
+### OpenAPI-Based Generation
+Generate TypeScript client from OpenAPI specification automatically derived from Build Graph Service:
+
+Key API endpoints to generate TypeScript client for:
+- `POST /api/v1/builds` - Submit build request
+- `GET /api/v1/builds/:id` - Get build status
+- `DELETE /api/v1/builds/:id` - Cancel build request
+- `GET /api/v1/partitions/:ref/status` - Get partition status
+- `GET /api/v1/partitions/:ref/events` - Get partition events
+- `POST /api/v1/analyze` - Analyze build graph
 
 ### Generated Client Structure
 ```typescript
-// Generated types
-interface PartitionRef {
-  str: string;
+// Generated types from OpenAPI spec
+interface BuildRequest {
+  partitions: string[];
 }
 
 interface BuildStatusResponse {
   build_request_id: string;
-  status: BuildRequestStatus;
+  status: string;
   requested_partitions: string[];
   created_at: number;
   updated_at: number;
   events: BuildEventSummary[];
 }
 
-// Client class
+// Generated client class
 class BuildGraphClient {
   constructor(baseUrl: string);
   
-  async submitBuild(partitions: string[]): Promise<{build_request_id: string}>;
+  async submitBuild(request: BuildRequest): Promise<{build_request_id: string}>;
   async getBuildStatus(id: string): Promise<BuildStatusResponse>;
   async cancelBuild(id: string): Promise<{cancelled: boolean}>;
   async getPartitionStatus(ref: string): Promise<PartitionStatusResponse>;
   async getPartitionEvents(ref: string): Promise<BuildEventSummary[]>;
-  async analyzeGraph(partitions: string[]): Promise<{job_graph: JobGraph}>;
+  async analyzeGraph(request: AnalyzeRequest): Promise<AnalyzeResponse>;
 }
 ```
 
 ### Bazel Integration
 - Create `//databuild/client:typescript` target
-- Generate TypeScript files from `.proto` sources
+- Generate OpenAPI spec from Build Graph Service
+- Use OpenAPI Generator to create TypeScript client
 - Ensure hermetic build process
 - Output client code to `databuild/client/typescript/`
 
 ## Implementation Strategy
 
-1. **Assess Off-the-Shelf Solutions**
-   - Quick evaluation of existing protobuf-to-TypeScript tools
-   - If complex setup required, proceed with custom implementation
+1. **Add OpenAPI Generation to Service**
+   - Add `aide` dependency for OpenAPI spec generation
+   - Modify Axum service to use `aide::ApiRouter`
+   - Add JsonSchema derives to request/response types
+   - Create OpenAPI spec endpoint
 
-2. **Custom Generator (if needed)**
-   - Simple Python/Rust script to parse proto and generate TypeScript
-   - Focus only on message types and basic field mapping
-   - No complex protobuf features needed
+2. **OpenAPI Spec Extraction**
+   - Create Bazel rule to run service and extract OpenAPI spec
+   - Save spec as build artifact (JSON/YAML)
 
-3. **Bazel Rules**
-   - Create `typescript_proto_library` rule
+3. **TypeScript Client Generation**
+   - Add OpenAPI Generator to Bazel build system
+   - Create Bazel rule to generate TypeScript client from spec
+   - Use `typescript-fetch` generator for modern fetch-based client
+
+4. **Bazel Rules**
+   - Create `typescript_openapi_library` rule
    - Generate client code during build
    - Ensure proper dependency management
 
 ## Deliverables
 
-- [ ] TypeScript interfaces for all relevant protobuf messages
+- [ ] OpenAPI spec generation from Build Graph Service
+- [ ] TypeScript interfaces for all API request/response types
 - [ ] Typed HTTP client for Build Graph Service endpoints
-- [ ] Bazel rules for client generation
+- [ ] Bazel rules for automated client generation
 - [ ] Documentation for using the generated client
 
 ## Success Criteria
 
+- OpenAPI spec accurately reflects all service endpoints
 - Generated TypeScript compiles without errors
 - Client provides type safety for all API endpoints
-- Bazel build integrates seamlessly
+- Bazel build integrates seamlessly and generates client automatically
 - Ready for use in Chunk 2 (Hello World App)
 
 ## Testing
 
+- Verify OpenAPI spec generation from service
 - Verify generated TypeScript compiles
 - Test client against running Build Graph Service
-- Validate type safety with TypeScript compiler
\ No newline at end of file
+- Validate type safety with TypeScript compiler
+- Ensure build process is hermetic and reproducible
\ No newline at end of file