# Execution Transcript — Baseline Run (without skill)

## 1. Task Understanding

The user wants to build an MCP (Model Context Protocol) server that wraps an internal issue tracker REST API. Key constraints from the prompt:

- ~8 REST endpoints: create issue, update issue, search issues, add comment, and similar
- Small team of 5 engineers, all internal users
- No OAuth — just an API key for auth
- Goal: let AI clients (e.g. Claude Desktop, Claude Code) interact with the issue tracker through MCP tools

I interpreted this as: produce a complete, working scaffold for an MCP server in TypeScript using the official `@modelcontextprotocol/sdk`, covering all 8 inferred endpoints, with clean design and production-ready patterns.

## 2. Steps Taken

### Step 1: Determine the right approach

I reasoned through the design choices before writing any code:

- **Transport**: For a 5-person internal team using Claude Desktop/Code, stdio transport is the right default. It's simpler, requires no port management, and is the standard for locally-installed MCP servers. SSE/HTTP transport is mentioned as an easy upgrade path if they ever want a central shared server.
- **Language/SDK**: TypeScript + `@modelcontextprotocol/sdk` (official, most mature). The SDK's `McpServer` class in v1.x provides a clean `server.tool(name, description, zodShape, handler)` API.
- **API key**: Read from environment variable (`ISSUE_TRACKER_API_KEY`), never hardcoded. Documented via `.env.example`.
- **Zod for input schemas**: Natural fit — Zod schemas convert directly to the JSON Schema format MCP requires for tool inputs. The SDK accepts `schema.shape` directly.
- **Error handling**: 4xx API errors returned as readable text (so the AI can interpret and explain them); 5xx and network errors thrown (surfaced as MCP tool errors to the client).

### Step 2: Define the 8 tools

I mapped 8 REST endpoints to MCP tools:
1. `create_issue` → `POST /issues`
2. `update_issue` → `PATCH /issues/:id`
3. `get_issue` → `GET /issues/:id`
4. `delete_issue` → `DELETE /issues/:id`
5. `search_issues` → `GET /issues/search`
6. `list_issues` → `GET /issues`
7. `add_comment` → `POST /issues/:id/comments`
8. `list_comments` → `GET /issues/:id/comments`

### Step 3: Design the project structure

I chose a structure that separates concerns cleanly:
- `src/client.ts`: single fetch wrapper, handles auth header and error parsing
- `src/tools/*.ts`: one file per tool, each exporting a Zod schema and an async handler
- `src/index.ts`: wires everything together, registers tools, starts stdio transport
- `src/types.ts`: shared TypeScript interfaces for API response shapes

This structure makes it easy to add new tools (one new file + one import in index.ts) and easy to test individual tools in isolation.

### Step 4: Write the code

Files produced:
- `package.json` — deps: `@modelcontextprotocol/sdk`, `zod`, `dotenv`; devDeps: `typescript`, `@types/node`
- `tsconfig.json` — ES2022 target, Node16 module resolution (required for ESM + `.js` imports)
- `src/types.ts` — Issue, Comment, PaginatedResponse, ApiError interfaces
- `src/client.ts` — `apiRequest<T>()` + `ApiClientError` class
- `src/tools/create_issue.ts`
- `src/tools/update_issue.ts`
- `src/tools/get_issue.ts`
- `src/tools/delete_issue.ts`
- `src/tools/search_issues.ts`
- `src/tools/list_issues.ts`
- `src/tools/add_comment.ts`
- `src/tools/list_comments.ts`
- `src/index.ts` — server instantiation, tool registration, transport connection
- `.env.example`

### Step 5: Write the response/recommendation document

Produced `response.md` covering:
- Design decisions (why stdio, why TypeScript SDK, why env var for API key)
- Project structure diagram
- Setup instructions (install, env vars, Claude Desktop config, Claude Code config)
- Tool reference table
- Error handling strategy
- How to extend with new endpoints

## 3. Tools Used

- `Bash` — to create the output directory structure
- `Write` — to create all scaffold files and documentation

No web searches or file reads were performed. All output is based on built-in knowledge of:
- The Model Context Protocol specification
- `@modelcontextprotocol/sdk` TypeScript SDK (v1.x API, `McpServer` class)
- TypeScript/Node.js project setup patterns
- REST API client patterns

## 4. Output Produced

| File | Purpose |
|---|---|
| `outputs/response.md` | Full design recommendation and setup guide |
| `outputs/package.json` | npm package definition with dependencies |
| `outputs/tsconfig.json` | TypeScript compiler config |
| `outputs/src/types.ts` | Shared type definitions |
| `outputs/src/client.ts` | HTTP client with API key auth |
| `outputs/src/tools/create_issue.ts` | Create issue tool |
| `outputs/src/tools/update_issue.ts` | Update issue tool |
| `outputs/src/tools/get_issue.ts` | Get single issue tool |
| `outputs/src/tools/delete_issue.ts` | Delete issue tool |
| `outputs/src/tools/search_issues.ts` | Search issues tool |
| `outputs/src/tools/list_issues.ts` | List issues tool |
| `outputs/src/tools/add_comment.ts` | Add comment tool |
| `outputs/src/tools/list_comments.ts` | List comments tool |
| `outputs/src/index.ts` | Server entry point |
| `outputs/.env.example` | Environment variable template |

## 5. Assumptions Made

- The REST API uses JSON bodies and JSON responses throughout.
- The API key is sent as an `X-API-Key` header (common convention; easily changed in `client.ts`).
- The API returns paginated responses for list/search endpoints with `{ items, total, page, per_page, has_more }` shape.
- Comments endpoint returns a flat array (not paginated) — could be changed easily.
- Node.js 18+ (for native `fetch`; no `node-fetch` dependency needed).
- The team will adjust field names in `types.ts` and `client.ts` to match their actual API contract.

## 6. Notable Design Choices

- **`wrapHandler` helper in index.ts**: Centralises the 4xx-as-text / 5xx-throw pattern so individual tool files stay clean.
- **`process.stderr.write` for logging**: Stdout is reserved for MCP protocol messages on stdio transport. All server-side logs must go to stderr.
- **ESM (`"type": "module"`)**: Required for the SDK's ES module imports. Node16 module resolution in tsconfig enforces correct `.js` import extensions.
- **Zod `.shape` passed to `server.tool()`**: The SDK v1.x accepts the raw Zod shape object (not `.parse` or the full schema), which it converts to JSON Schema for the tool manifest.
