Onegent/ Developers
Docs/MCP · streamable HTTP/ChatGPT Apps

ChatGPT — Onegent integration #

Onegent — AI books your trip end-to-end.

ChatGPT does not natively speak MCP stdio, so the Claude Desktop recipe in claude-mcp.md doesn't apply. ChatGPT integrates via two paths, both supported by this package.

PathStatusBest for
ChatGPT Apps SDKPreviewPublic directory distribution
Custom GPT ActionAvailablePrivate teams, immediate use

The new ChatGPT Apps SDK uses MCP over Streamable HTTP. Onegent's @onegent/mcp-server package supports HTTP mode natively:

onegent-mcp-server --http --port 3333

Architecture #

User in ChatGPT
      │
      ▼
  OpenAI ────────► HTTPS ────────► @onegent/mcp-server --http
                                          │
                                          ▼
                                 https://onegent.one/api/v1/*

OpenAI routes the user's natural-language request to an MCP server you've registered. Your MCP server calls Onegent's REST API with the user's scoped API key.

Preparing the submission #

  1. Host the HTTP MCP server at a stable HTTPS URL. Options:

    • Onegent-hosted (recommended): we're deploying https://onegent.one/api/mcp in v0.2.37+. Third parties can use this directly — no self-hosting required. You'd submit an "app" that proxies to our endpoint.
    • Self-host: run the package on Fly, Cloud Run, Railway, or any HTTPS-terminating platform. Reverse-proxy 443 → the container's 3333.

  2. Prepare the manifest. Start from the template at packages/mcp-server/chatgpt-apps/manifest.json. Key fields:

    {
  "name": "Travel Booking Agent",
  "description": "Book restaurants, hotels, flights, and activities through an AI agent that navigates real booking sites.",
  "mcp": {
    "url": "https://your-host.example.com/",
    "transport": "streamable_http",
    "auth": { "type": "api_key", "headerName": "Authorization", "headerPrefix": "Bearer " }
  }
}

    ⚠ Always validate against the latest OpenAI schema before submission. Field names above reflect the MCP-era spec and may shift while Apps SDK is in preview.

  3. Submit at https://platform.openai.com/apps (account with Apps access required). Review typically takes 5–10 business days. Expect questions about the payment-safety model — link to the "Payment safety" section in claude-mcp.md.

Auth: how users paste their key #

ChatGPT Apps lets users attach an API key during app install. When the user talks to the app, ChatGPT includes the key in the MCP request's Authorization header. @onegent/mcp-server reads this transparently via ONEGENT_API_KEY env fallback — but for hosted Apps, OpenAI populates the header directly and there's no local env.

Test this with curl to confirm before submitting:

curl -X POST https://your-host.example.com/ \
  -H "Authorization: Bearer ogk_test_xxx" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}'

You should get an SSE response listing all 6 tools.

2. Custom GPT Action (available today) #

The older but still-supported Custom GPT path lets you build a private GPT that calls Onegent's REST API via an OpenAPI spec. This bypasses MCP entirely but works out of the box with no approval process.

Setup #

  1. Go to chatgpt.com/gpts/editor → Create

  2. In Configure → Actions → Create new action

  3. Paste this OpenAPI 3.1 spec (abridged; the full surface is in docs/api/v1.md):

    openapi: 3.1.0
info:
  title: Onegent Travel Booking Execution API
  version: "1"
servers:
  - url: https://onegent.one/api/v1
paths:
  /execution-jobs:
    post:
      operationId: createExecutionJob
      summary: Start a booking job
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                request:
                  type: object
                  properties:
                    scenario: { type: string, enum: [restaurant, hotel, flight, activity] }
                    params: { type: object }
                profile:
                  type: object
              required: [request]
      responses:
        "202":
          description: Job created
  /execution-jobs/{jobId}:
    get:
      operationId: getExecutionJob
      parameters:
        - in: path
          name: jobId
          required: true
          schema: { type: string }
      responses:
        "200": { description: Job status }
components:
  securitySchemes:
    bearer:
      type: http
      scheme: bearer
security:
  - bearer: []

  4. In Authentication, select API Key → Custom (Bearer). Paste your ogk_live_... key.

  5. In the GPT's instructions, paste:

    You help users book restaurants, hotels, flights, and activities. Use the Onegent API: POST /execution-jobs to start, then GET /execution-jobs/ to poll. The agent pauses for payment at status "paused_payment" — tell the user to confirm in their Onegent app.

  6. Save. Test in the editor.

Limitations of Custom GPT #

  • Only available to your personal account (or your team's, with Team/Enterprise plans)
  • Cannot be listed in the GPT Store as of April 2026 for third-party-API actions that aren't pre-approved
  • Requires user to paste their key during GPT setup (not per-conversation)
  • No MCP instructions/resources support — ChatGPT just sees the OpenAPI shape

For everything past an internal demo, submit via the Apps SDK path above.

Reference #