---
phase: 26-add-oauth-support-to-load-testing
plan: 01
subsystem: auth
tags: [oauth, pkce, device-code, middleware, feature-flag]

# Dependency graph
requires:
  - phase: 25-loadtest-config-upload
    provides: "cargo-pmcp loadtest infrastructure"
provides:
  - "OAuthHelper at pmcp::client::oauth behind oauth feature flag"
  - "OAuthConfig struct for configuring OAuth flows"
  - "create_oauth_middleware convenience function"
  - "default_cache_path for token caching at ~/.pmcp/oauth-tokens.json"
affects: [26-02, 26-03, 26-04, cargo-pmcp-loadtest]

# Tech tracking
tech-stack:
  added: [webbrowser 1.x, dirs 6.x, rand 0.10]
  patterns: [feature-gated oauth module, tracing-based output instead of colored]

key-files:
  created:
    - src/client/oauth.rs
  modified:
    - Cargo.toml
    - src/client/mod.rs

key-decisions:
  - "Changed token cache path from ~/.mcp-tester/ to ~/.pmcp/oauth-tokens.json for SDK consistency"
  - "All terminal output uses tracing (info/warn/debug/error) instead of colored crate"
  - "Module double-gated: not(wasm32) + feature oauth"

patterns-established:
  - "Feature-gated optional modules: #[cfg(all(not(target_arch = \"wasm32\"), feature = \"oauth\"))]"
  - "Error conversion pattern: .map_err(|e| Error::internal(format!(\"...: {e}\")))"

requirements-completed: [OAUTH-01, OAUTH-02]

# Metrics
duration: 4min
completed: 2026-03-01
---

# Phase 26 Plan 01: Extract OAuthHelper to Core SDK Summary

**OAuthHelper with PKCE and device code flows moved from mcp-tester to pmcp::client::oauth behind feature-gated `oauth` flag**

## Performance

- **Duration:** 4 min
- **Started:** 2026-03-01T02:13:44Z
- **Completed:** 2026-03-01T02:18:13Z
- **Tasks:** 2
- **Files modified:** 3

## Accomplishments
- Extracted OAuthHelper from crates/mcp-tester into core SDK at src/client/oauth.rs
- Added `oauth` feature flag with webbrowser, dirs, rand as optional dependencies
- Replaced all anyhow error handling with pmcp::error::Error
- Replaced all colored terminal output with tracing calls
- Added create_oauth_middleware convenience function

## Task Commits

Each task was committed atomically:

1. **Task 1: Add oauth feature flag and dependencies to Cargo.toml** - `d716a59` (feat)
2. **Task 2: Create src/client/oauth.rs and wire into mod.rs** - `6e578a7` (feat)

## Files Created/Modified
- `Cargo.toml` - Added oauth feature flag with webbrowser, dirs, rand optional deps
- `src/client/oauth.rs` - OAuthHelper, OAuthConfig, default_cache_path, create_oauth_middleware
- `src/client/mod.rs` - Added feature-gated pub mod oauth

## Decisions Made
- Changed token cache path from `~/.mcp-tester/tokens.json` to `~/.pmcp/oauth-tokens.json` for SDK consistency (not tied to mcp-tester binary)
- All colored terminal output replaced with tracing calls -- no colored crate dependency added to pmcp
- Module is double-gated with both `not(wasm32)` and `feature = "oauth"` since oauth uses tokio::net::TcpListener and webbrowser which are unavailable on WASM

## Deviations from Plan

### Auto-fixed Issues

**1. [Rule 1 - Bug] Added missing Debug derive for OAuthHelper**
- **Found during:** Task 2 (Create src/client/oauth.rs)
- **Issue:** Compiler warning for missing Debug implementation (`missing_debug_implementations` lint enabled in src/lib.rs)
- **Fix:** Added `#[derive(Debug)]` to OAuthHelper struct
- **Files modified:** src/client/oauth.rs
- **Verification:** cargo build -p pmcp --features oauth compiles without warnings
- **Committed in:** 6e578a7 (Task 2 commit)

---

**Total deviations:** 1 auto-fixed (1 bug)
**Impact on plan:** Trivial fix required by project lint settings. No scope creep.

## Issues Encountered
None

## User Setup Required
None - no external service configuration required.

## Next Phase Readiness
- OAuthHelper is now available at pmcp::client::oauth for any consumer
- Ready for Plan 02 (wire OAuthHelper into cargo-pmcp loadtest command)
- Ready for Plan 03 (update mcp-tester to import from pmcp instead of its own copy)

## Self-Check: PASSED

All files verified present, all commits verified in git log.

---
*Phase: 26-add-oauth-support-to-load-testing*
*Completed: 2026-03-01*
