MCP

Overview

Apender exposes a stdio MCP server that forwards tool calls to the API. The repo stays on disk; intent, answers, and optional project metadata are sent over HTTPS. Host-specific file locations: Integration guides.

Environment variables

Set these in the MCP host config (Cursor, Claude Code, etc.):

APD_API_URL

API base URL from Dashboard → API keys. This is where the MCP server sends requests — not your app’s URL.

APD_API_KEY

The apd_live_… key from the same page. Env or secret store only — not git.

APD_WORKSPACE_ROOT

Absolute path to the git repo root. Used for project context sent with sessions.

Example MCP server block (replace placeholders):

{
  "mcpServers": {
    "apender": {
      "command": "node",
      "args": ["/absolute/path/to/apender-mcp-server"],
      "env": {
        "APD_API_URL": "<API base URL from Dashboard → API keys>",
        "APD_API_KEY": "apd_live_your_key",
        "APD_WORKSPACE_ROOT": "/absolute/path/to/git/repo"
      }
    }
  }
}

Tools the agent can call

runtime_startSession

Start engineering or simple session from intent

runtime_message

Gateway message / follow-up

runtime_answerQuestion

Submit user answers when halted

runtime_getSession

Poll session state

runtime_getSpecification

Fetch compiled specification

runtime_getSimpleTaskBrief

Simple-path brief

runtime_syncProjectIntelligence

Refresh PIG for workspace

runtime_detectProjectIdentity

Detect git remote / workspace identity

runtime_discoverRepository

Discovery-only pass

runtime_getProjectGraph

PIG snapshot for session

Typical workflow

1. Agent calls runtime_startSession with the intent string.
2. If the response asks for input, the agent surfaces questions in chat, then calls runtime_answerQuestion.
3. When complete, the agent fetches the plan and edits the repo with normal file tools.

Cursor rules (recommended)

MCP exposes tools; it does not force the agent to use them on every task. Add a project rule so Cursor routes implementation work through Apender before editing code. Copy the snippet into .cursor/rules/apender.mdc at your repo root (create the folder if needed).

Set alwaysApply: true in the frontmatter for every chat, or use alwaysApply: false with globs (e.g. **/*) if you only want the rule when certain files are in context.

---
description: Route implementation work through Apender MCP before editing code
alwaysApply: true
---

# Apender engineering runtime (MCP)

You are the **Builder** in the IDE. **Apender** is the engineering runtime. Use Apender MCP tools for implementation work before changing application code.

## When to use Apender

Call the runtime when the user asks you to **build, change, or fix product behavior** (features, refactors, integrations, non-trivial bugs). Skip Apender only when the user explicitly says to skip it, or for **read-only** tasks (explain code, review, search) and **mechanical** edits (typo, format-only) with no behavior change.

## Required workflow

1. Call `runtime_startSession` with a clear intent string (or `runtime_message` to continue an existing session).
2. If `status === "waiting_user"` or `builderDirective.halt === true`:
   - **Stop** all coding and file edits immediately.
   - Ask the user **every** question in `builderDirective.questionsToAsk` / `pendingQuestions` (use the question text verbatim).
   - After the user answers, call `runtime_answerQuestion` with `{ sessionId, answers: { [key]: reply } }` (`single_choice`: string; `multi_choice`: string[]; `free_text`: string).
   - Do **not** invent answers, skip questions, or call `runtime_getSpecification` while halted.
3. Poll with `runtime_getSession` until `status === "completed"` (or handle `failed` with the user).
4. Call `runtime_getSpecification`, then implement from that specification using normal file tools.

## Scope changes

If requirements change materially after a spec exists, send `runtime_message` or start a new session — do not silently drift from the approved plan.

## Prerequisites

Apender MCP must be configured (`APD_API_KEY`, `APD_API_URL`, `APD_WORKSPACE_ROOT`). See project docs or Dashboard → API keys.

Cursor-specific MCP file location: Cursor integration.