SKILL.md
Full skill instructions
Codex Machine Payment Protocol (MPP)
Use this skill when the Codex Supergraph returns a 402 Payment Required response. The MPP challenge flow lets you pay per query without needing an API key. For higher volume, get an API key at dashboard.codex.io/signup — see docs.codex.io for details.
| HTTP endpoint | https://graph.codex.io/graphql |
| Credential header | Authorization: Payment <base64url-credential> |
How it works
- Send a GraphQL query (no credential).
- Server returns
402 Payment RequiredwithWWW-Authenticate: Payment ...challenges. - Client solves one challenge and retries with
Authorization: Payment <credential>. - Server returns GraphQL data +
Payment-Receiptheader.
Constraints
- Query only. Mutations and subscriptions return
403in MPP mode. - If a valid API key or bearer token is also present, API auth takes precedence.
Rules
- Never print raw credentials.
- Only use MPP for
queryoperations. - Before constructing any query, read
references/query-templates.mdbelow for the correct GraphQL schema. Do not guess query or field names.
References
| File | Purpose |
|---|---|
| ../codex-supergraph/references/query-templates.md | GraphQL query schema and examples — read before constructing queries |
| ../codex-supergraph/references/gotchas.md | Common query failure points |
| references/gotchas.md | MPP-specific failure points |
| rules/wallets.md | Wallet setup: tempo wallet/request (Tempo) |
| references/mpp-flow.md | Auth matrix, challenge details, error codes |
Links
- Website: www.codex.io
- Documentation: docs.codex.io
- Get an API key: dashboard.codex.io/signup
