---
title: "Callback"
method: GET
path: "/callback"
tags: ["mcp"]
---

# Callback

`GET /callback`

OAuth 2.0 authorization response handler for MCP loopback clients.

Accepts either:

- A successful authorization response (``code`` + ``state``), which is
  forwarded back to the validated client ``redirect_uri`` with the
  original (un-wrapped) ``state``.
- An error response (``error``[+``error_description``/``error_uri``]), per
  RFC 6749 §4.1.2.1. When ``state`` is present and decodes to a trusted
  ``redirect_uri``, the error params are propagated back to the client so
  its OAuth library can surface them. Otherwise we render an HTML error
  page so the user is not left on an opaque 422 / blank screen.

## Query parameters

- `code` string, nullable
- `state` string, nullable
- `error` string, nullable
- `error_description` string, nullable
- `error_uri` string, nullable

## Response `200`

Successful Response

- unknown

## Other responses

- `422` — Validation Error

## Changes

- **2026-09-24** `731afbea6a1b` — 2 info
  - api tag `mcp` added
  - api tag `mcp_discoverable` removed
- **2026-09-23** `7ed45f30a5f0` — 2 info
  - api tag `mcp_discoverable` added
  - api tag `mcp` removed
- **2026-09-21** `6246f8d427b7` — 2 info
  - api tag `mcp` added
  - api tag `mcp_discoverable` removed
- **2026-09-20** `3b2b241e4b0b` — 2 info
  - api tag `mcp_discoverable` added
  - api tag `mcp` removed
- **2026-09-18** `082b5fabd909` — 1 info
  - endpoint added

[Full history](https://skmtc.dev/flock/apis/litellm-api/changes/callback/get.md)

---

[API](https://skmtc.dev/flock/apis/litellm-api.md) · [All operations](https://skmtc.dev/flock/apis/litellm-api/llms.txt) · [OpenAPI document](https://skmtc.dev/flock/apis/litellm-api/revisions/731afbea6a1b?raw)