feat: Claude Desktop parity finalization (v1.19.x)

[typelicious]

Objective

Finalize Claude Desktop parity to make Claude Desktop a first-class client with stable local endpoint configuration and reliable desktop-specific workflows.

Context

From roadmap v1.19.x: Claude Desktop Parity Finalization is the next priority after achieving Claude Code parity (v1.18.0). The bridge is production-ready for Claude Code but needs desktop-specific hardening.

Current Status (v1.18.0)

• ✅ Anthropic bridge SSE streaming implemented
• ✅ Tool result continuity working
• ✅ Claude Code model ID aliasing built-in
• ✅ Basic header/version compatibility
• ⚠️ Desktop endpoint override flows need implementation
• ⚠️ Desktop-specific compatibility hardening required
• ⚠️ Real workflow validation with Claude Desktop pending

Implementation Slices

1. Desktop Endpoint Override Flows

• Stable local endpoint configuration support for Claude Desktop
• Clear troubleshooting guides and setup documentation
• Validation against real Claude Desktop installation and workflows

2. Bridge Hardening for Desktop Use

• Enhanced header/version/beta compatibility for desktop-specific headers
• Session continuity validation under desktop usage patterns
• Error mapping improvements for desktop-specific error cases
• Exact token counting integration (if feasible)

3. Desktop Workflow Validation

• Real workflow testing with Claude Desktop (install, configure, daily use)
• Common papercut identification and fixes
• Performance and stability validation under desktop usage patterns
• Documentation of known limitations and workarounds

Success Criteria

• Operators can configure Claude Desktop to use local Gate without recurring compatibility issues
• Desktop sessions feel stable and production-ready (no "experimental" feeling)
• Bridge parity gaps are documented and addressed
• Real user workflow validation confirms parity

Related Issues

• Design: Robust external metadata integration with improved model/provider mapping (v1.16.0) #186: External Metadata Integration (v1.20.x)
• Roadmap: docs/FAIGATE-ROADMAP.md

Labels

• parity:desktop
• roadmap:v1.19
• priority:high
• component:bridge