How do I install the Codex Gateway skill?

Run npx skillmds@latest add codex-data/codex-gateway in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Codex Gateway safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Codex Gateway?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Codex Gateway free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Codex Gateway?

codex-data (@codex-data) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Codex Gateway by codex-data — Agent Skill

Name: Codex Gateway
Author: codex-data

File contents

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 Required with WWW-Authenticate: Payment ... challenges.
Client solves one challenge and retries with Authorization: Payment <credential>.
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

Links

Website: www.codex.io
Documentation: docs.codex.io
Get an API key: dashboard.codex.io/signup

---name: codex-gatewaydescription: Use when the user wants to query the Codex Supergraph and the server returns a 402 challenge. Pays per query via the MPP 402 challenge flow. Only supports queries, not mutations or subscriptions.---# Codex Machine Payment Protocol (MPP)Use this skill when the [Codex](https://www.codex.io) 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](https://dashboard.codex.io/signup) — see [docs.codex.io](https://docs.codex.io) for details.| | || --------------------- | --------------------------------------------------------------- || HTTP endpoint | `https://graph.codex.io/graphql` || Credential header | `Authorization: Payment <base64url-credential>` |## How it works1. 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](../codex-supergraph/references/query-templates.md) | **GraphQL query schema and examples — read before constructing queries** || [../codex-supergraph/references/gotchas.md](../codex-supergraph/references/gotchas.md) | Common query failure points || [references/gotchas.md](references/gotchas.md) | MPP-specific failure points || [rules/wallets.md](rules/wallets.md) | Wallet setup: tempo wallet/request (Tempo) || [references/mpp-flow.md](references/mpp-flow.md) | Auth matrix, challenge details, error codes |## Links- Website: [www.codex.io](https://www.codex.io)- Documentation: [docs.codex.io](https://docs.codex.io)- Get an API key: [dashboard.codex.io/signup](https://dashboard.codex.io/signup)

Frequently asked questions

Codex Gateway