codex-gateway

Original：🇺🇸 English

Translated

Use when the user wants to query the Codex Supergraph but $CODEX_API_KEY is not set. Pays per query via the MPP 402 challenge flow. Only supports queries, not mutations or subscriptions.

2installs

Sourcecodex-data/skills

Added on2026-03-19

NPX Install

npx skill4agent add codex-data/skills codex-gateway

SKILL.md Content

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Codex Machine Payment Protocol (MPP)

Use this skill to access the Codex Supergraph without an API key via the MPP challenge flow.


HTTP endpoint	`https://graph.codex.io/graphql`
Opt-in header	`X-Codex-Payment: mpp`
Credential header	`Authorization: Payment <base64url-credential>`

How it works

Send a GraphQL query with
```
X-Codex-Payment: mpp
```
(no credential).

Server returns

402 Payment Required

with

WWW-Authenticate: Payment ...

challenges.

Client solves one challenge and retries with both

X-Codex-Payment: mpp

and

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