docs: complete phase 3 prompt builders

AGENT_HANDOFF.md

@@ -1,9 +1,45 @@
 # AGENT_HANDOFF.md
 
-Read ARCHITECTURE.md before making changes.
+## Completed
 
-Rules:
+### Phase 0 — Repository Setup
+- Repository skeleton (TASK 0.1)
+- package.json with dependencies (TASK 0.2)
 
+### Phase 1 — Core Utilities
+- Configuration loader (`src/config/env.js`) — TASK 1.1
+- Secret redaction utility (`src/utils/redact.js`) — TASK 1.2
+- Context budget utility (`src/utils/context-budget.js`) — TASK 1.3
+- Safe logging helper (`src/utils/logging.js`) — TASK 1.4
+
+### Phase 2 — OpenAI Integration
+- OpenAI client wrapper (`src/openai/client.js`) — TASK 2.1
+- Response builder (`src/openai/responses.js`) — TASK 2.2
+- Error handling and edge cases (tests) — TASK 2.3
+
+### Phase 3 — Tool Inputs and Prompts
+- Zod input validation schemas (`src/tools/schemas.js`, tests) — TASK 3.1
+- Base prompt template (`src/prompts/base.js`, tests) — TASK 3.2
+- ask_chatgpt prompt builder (`src/prompts/ask-chatgpt.js`, tests) — TASK 3.3
+- review_plan prompt builder (`src/prompts/review-plan.js`, tests) — TASK 3.4
+- review_code prompt builder (`src/prompts/review-code.js`, tests) — TASK 3.5
+- debug_issue prompt builder (`src/prompts/debug-issue.js`, tests) — TASK 3.6
+- architecture_review prompt builder (`src/prompts/architecture-review.js`, tests) — TASK 3.7
+
+## Next Phase
+
+### Phase 4 - Tool Handlers
+
+Build the MCP tool handlers that:
+1. Register each tool with the MCP server.
+2. Validate input using `schemas.js`.
+3. Call the appropriate prompt builder.
+4. Send the prompt to OpenAI via `responses.js`.
+5. Return structured advisory output to Claude Code.
+
+## General Rules
+
+- Read ARCHITECTURE.md before making changes.
 - Work incrementally.
 - Keep changes small.
 - Do not implement multiple phases at once.