composer-api-docker

Docker packaging of standardagents/composer-api ("API for Cursor") for Dokploy/g5kc: OpenAI-compatible /v1 server backed by Cursor Composer models via @cursor/sdk.

Why this repo

Upstream (301 stars, actively maintained, MIT) ships a macOS app plus cross-platform Node scripts. This image builds the ElCabrii/composer-api-local fork (upstream + a local/ Node wrapper that serves /v1/chat/completions, /v1/responses, /v1/models on Linux/Windows/WSL), pinned at commit fbe06a0a6328, and runs it in Node 22.

Runtime facts:

• No Cursor IDE required; only a Cursor user API key (crsr_...) from https://cursor.com/dashboard/api.
• Usage bills to your Cursor plan request pool (usage dashboard "SDK" tag).
• It is an agent API, not raw inference: no temperature/top_p; Responses API rejects tools (use chat completions for client tool loops).

Deploy status (g5kc / Dokploy)

• Dokploy project composer-api (env production), compose service composer-api (custom git + SSH key deploy from this repo, branch main).
• Container composer-api, image g5kc/composer-api:latest, maps loopback 127.0.0.1:8788 (8787 is taken by portkey-gateway on g5kc).
• Tailnet: tailscale serve --bg --https=8788 http://127.0.0.1:8788 → https://g5kc.tail1e9037.ts.net:8788/v1 (tailnet only).
• Env in Dokploy: CURSOR_API_KEY= (paste the key), CURSOR_API_PORT=8788.

Deploy (from scratch)

1. Dokploy → new Project (e.g. composer-api).
2. Compose app from this repo (lkonga/composer-api-docker, branch main, path docker-compose.yml) — use a read-only SSH deploy key: add pubkey to GitHub repo, register in Dokploy, set compose sourceType=git, customGitUrl=git@github.com:lkonga/composer-api-docker.git, customGitSSHKeyId=<id>. (sourceType=github requires the Dokploy Github Provider OAuth.)
3. Env: set CURSOR_API_KEY=crsr_... and CURSOR_API_PORT=8788.
4. After deploy: tailscale serve --bg --https=8788 http://127.0.0.1:8788.

Verify (after pasting the key + redeploy)

CURSOR_API_KEY=crsr_... ./smoke-test.sh
# or against the loopback endpoint:
BASE_URL=http://127.0.0.1:8788 CURSOR_API_KEY=crsr_... ./smoke-test.sh

Exits 0 only when /health passes AND a real /v1/chat/completions round-trip returns. Fails with a clear message if the key is missing or the API errors.

Usage

curl https://g5kc.tail1e9037.ts.net:8788/v1/models \
  -H "Authorization: Bearer crsr_..."

curl https://g5kc.tail1e9037.ts.net:8788/v1/chat/completions \
  -H "Authorization: Bearer crsr_..." -H "Content-Type: application/json" \
  -d '{"model":"composer-2.5","messages":[{"role":"user","content":"Hello"}]}'

OpenCode/Codex: point at the /v1 base URL with any bearer token when CURSOR_API_KEY is set server-side.

Caveats

• Cursor ToS/commercial-use question is open upstream (standardagents/composer-api #15); keep the endpoint tailnet-only.
• reasoning.effort forwarding has an open upstream gap (#28).