MCP Auth Fixture

Minimal mock MCP server for testing auth (dynamic API key + username/password). Deployable on Vercel.

Endpoints

Modes

• success — auth ok, tool returns payload

• business_403 — ordinary business 403

• structured_invalid_403 — structured invalid credential 403

Expected credentials (defaults)

• Dynamic header: X-E2E-Key: local-e2e-secret

• Username / password: local-user / local-password

Override via env: EXPECTED_DYNAMIC_KEY, EXPECTED_USERNAME, EXPECTED_PASSWORD.

Related MCP server: Cloud Run MCP Server

Deploy to Vercel

1. Import this repo in Vercel.

2. Framework: Other / no build command.

3. Optional: set the three env vars above.

4. MCP URL after deploy:

https://<your-deployment>.vercel.app/mcp

Local

node server.mjs
# -> http://127.0.0.1:8788/mcp

# Or
npx vercel dev

Smoke

curl -s "$BASE/health"
curl -s -X POST "$BASE/mcp" -H 'content-type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-03-26"}}'
curl -s -X POST "$BASE/mcp" -H 'content-type: application/json' -H 'X-E2E-Key: local-e2e-secret' \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"check_dynamic_auth","arguments":{"message":"hi"}}}'

Notes

• mode / events live in process memory and reset on cold start. Fine for fixtures; not durable multi-instance audit.