PlanetGraph API Auth and Error Guide

Authentication
Preferred for agents:
- X-API-Key header

Alternative:
- Authorization: Bearer <firebase_id_token>

Swagger usage
- Open https://api.planetgraph.com/docs
- Click Authorize
- Fill ApiKeyAuth (X-API-Key)

Common errors
- 400 Bad Request: invalid parameters or unsupported query structure
- 401 Unauthorized: missing or invalid credentials
- 403 Forbidden: role/ownership violation
- 404 Not Found: resource does not exist or is deleted
- 409 Conflict: resource in conflicting state
- 429 Too Many Requests: rate limit exceeded

Troubleshooting checklist
1) Verify auth header present.
2) Verify endpoint path and method.
3) Verify filter semantics (edge type vs node type).
4) Reduce filters and test baseline list endpoint.