HTTP API

The server speaks the subset of Anthropic and OpenAI protocols needed by Claude Code and the optional Codex native passthrough.

No client authentication. The listener accepts requests without validating `Authorization` or `x-api-key`. Loopback is the default. Protect every non-loopback listener with a firewall or authenticating reverse proxy.

GET /healthz

Liveness check:

{"ok":true}

It does not verify provider credentials or upstream availability.

POST /v1/messages

Accepts an Anthropic Messages request in streaming or non-streaming mode. POST /v1/messages?beta=true reaches the same route.

The request model selects the provider. The proxy translates supported message content, system prompts, thinking settings, tool definitions, tool choice, tool calls, tool results, images, output configuration, metadata, and streaming behavior according to the provider.

Streaming responses use Anthropic SSE events such as message_start, content_block_start, content_block_delta, content_block_stop, message_delta, and message_stop. Non-streaming requests are accumulated from the provider’s stream.

Unknown models return HTTP 400 with the supported catalog. Missing provider auth returns HTTP 401.

POST /v1/messages/count_tokens

Accepts the same basic Anthropic request shape and returns:

{"input_tokens":1234}

Codex, Kimi, and Grok use a local gpt-tokenizer estimate with o200k_base. Cursor estimates the rendered prompt from its character length. Counts support Claude Code compaction behavior and are estimates rather than provider billing values.

GET /v1/models

Returns Anthropic-shaped model discovery:

{
  "data": [
    {
      "type": "model",
      "id": "gpt-5.6-sol",
      "display_name": "gpt-5.6-sol (codex)"
    }
  ],
  "has_more": false,
  "first_id": "gpt-5.6-sol",
  "last_id": "cursor:gpt-5.5"
}

An optional limit query truncates data and sets has_more. The route does not expose a pagination cursor.

Claude Code gateway discovery filters IDs according to its own model rules. See Models and routing.

POST /v1/responses

This route exists only when CCP_CODEX_RESPONSES_API=1 or codex.responsesApi is true. It accepts a native OpenAI Responses request for a registered Codex model.

The proxy:

• validates the model against the Codex catalog
• replaces incoming auth with proxy-owned ChatGPT Codex auth
• refreshes rejected access tokens before forwarding a response
• preserves native JSON responses and SSE bodies
• records the request in the monitor and optional traffic capture

It does not implement Images API, stored response retrieval or deletion, or WebSocket client ingress.

Other routes

Unmatched paths return the proxy’s not-found response. The server has no administrative mutation API, credential API, or remote shutdown route.