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[Client] Implement OAuth 2.0 Authorization Code flow with PKCE (RFC 6749 + RFC 7636)

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#319 1 comment 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
35/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Quiet
Tech stack
php

Research direction

Start by reviewing dependencies #315, #316, #317, and #318, then inspect Mcp\Client\Auth\Grant\AuthorizationCodeGrant and TokenStorageInterface. Trace the authorization and token endpoints before defining the user-agent and redirect-handler integration. Done means PKCE and state-validation unit tests pass and the auth/basic-cimd conformance scenario passes.

Written by the indexing model from the issue text.

Description

auth Client enhancement improves spec compliance

Context

Primary user-facing flow. Required for any interactive MCP client to obtain tokens after PRM/AS discovery.

Scope

  • Mcp\Client\Auth\Grant\AuthorizationCodeGrant:
    • Generate PKCE code_verifier + code_challenge (S256).
    • Build authorize URL with client_id, redirect_uri, response_type=code, code_challenge, code_challenge_method, scope, state, resource (audience-binding RFC 8707).
    • Pluggable user-agent dispatcher: callback hook so library users can open a browser / present URL in CLI.
    • Local loopback redirect listener (default) or custom redirect handler.
    • Exchange code → tokens at token_endpoint; persist via TokenStorageInterface.
  • Verify state round-trip; reject mismatched.

Conformance scenarios unblocked

auth/basic-cimd and prerequisite for all scope/refresh/cross-app scenarios.

Dependencies

Blocked by: #315, #316, #317, #318. Pairs with #319 (token endpoint auth methods).

Acceptance

  • Unit tests for PKCE generation + state validation.
  • Conformance: auth/basic-cimd passes.

cc @soyuka

Dominant language
PHP
Stars
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Forks
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Avg merge
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Merged PRs (30d)
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