codex-gateway

Installation
SKILL.md

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.

HTTP endpoint https://graph.codex.io/graphql
Credential header Authorization: Payment <base64url-credential>

How it works

  1. Send a GraphQL query (no credential).
  2. Server returns 402 Payment Required with WWW-Authenticate: Payment ... challenges.
  3. Client solves one challenge and retries with Authorization: Payment <credential>.
  4. Server returns GraphQL data + Payment-Receipt header.

Constraints

  • Query only. Mutations and subscriptions return 403 in 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 query operations.
  • Before constructing any query, read references/query-templates.md below 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
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104
First Seen
Mar 18, 2026