Authenticate an AI agent's GraphQL requests to Linear using either a personal API key or an OAuth 2.0 access token

Documented steps

1. For single-user/script agents, generate a Personal API Key from Linear's Security & access settings, then send it as-is (no 'Bearer' prefix) in the request header: Authorization: <API_KEY>.
2. For multi-user apps, redirect users to https://linear.app/oauth/authorize with client_id, redirect_uri, response_type=code, a comma-separated scope list, and a state value (docs say it 'should always be supplied' to prevent CSRF).
3. Exchange the returned code at the token endpoint https://api.linear.app/oauth/token using grant_type=authorization_code to get an access_token; use grant_type=refresh_token later to renew it.
4. Call the API by POSTing JSON to https://api.linear.app/graphql with headers Content-Type: application/json and Authorization: Bearer <ACCESS_TOKEN> (OAuth) — body shape is {"query": "..."}.
5. Pick scopes matching the task, e.g. read, write, issues:create, comments:create, timeSchedule:write, or admin, rather than requesting broad access by default.
6. Always inspect the response body's errors array even on HTTP 200 — GraphQL requests 'can partially succeed', returning data alongside per-field errors.
7. Official docs: https://linear.app/developers/graphql and https://linear.app/developers/oauth-2-0-authentication