[FEATURE] GitHub Issue Assignment Auto-Trigger for Claude Code Web UI

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When using Claude Code Web UI (claude.ai/code), there's no way to automatically trigger a session from GitHub issue assignments. The current workflow requires manual duplication of effort:

Current painful workflow:

1. Create a detailed issue in GitHub with bug description/feature requirements
2. Open Claude Code Web UI
3. Select the repository
4. Manually re-type or copy-paste the same issue description that already exists in GitHub
5. Claude works on it and creates a PR
6. Manually add the issue reference to the PR (e.g., "Fixes #123")

What I want:

1. Create an issue in GitHub
2. Assign issue to @claude (or add a label like claude-code)
3. Claude Code Web UI automatically picks up the issue and starts a session
4. Claude implements the fix and creates a PR **with the issue number automatically

Proposed Solution

Add GitHub webhook integration to Claude Code Web UI that:

1. Listens for issue assignment events - When an issue is assigned to a configured user (e.g., claude or claude-bot), automatically start a Claude Code session
2. Auto-populates the task context - Pull the issue title, description, labels, and comments directly into the session
3. Links PRs to issues automatically - When Claude creates a PR, include Fixes #<issue-number> in the PR description
4. Shows pending issues in the UI - Display a queue/notification of assigned issues waiting for action

Suggested Implementation

┌─────────────────┐         ┌──────────────────────┐         ┌─────────────────┐
│  GitHub Issue   │         │   Anthropic Cloud    │         │ Claude Code     │
│  (assigned to   │ ──────► │   Webhook Handler    │ ──────► │ Web UI Session  │
│   @claude)      │         │                      │         │ (auto-started)  │
└─────────────────┘         └──────────────────────┘         └─────────────────┘
                                     │
                                     ▼
                            ┌──────────────────────┐
                            │  Issue context auto- │
                            │  loaded into session │
                            └──────────────────────┘

Configuration Options (in Claude Code settings)

• Trigger method: Issue assignment / Label added / Both
• Assignee username: claude (customizable)
• Label trigger: claude-code (customizable)
• Auto-start session: Yes/No (could show notification instead)
• Repository allowlist: Only trigger for specific repos

Alternative Solutions

| Alternative | Why It's Not Ideal |
|-------------|-------------------|
| Claude Code GitHub Action | Runs in CI environment, not the Web UI. Different UX, no interactive session. |
| Copy-paste issue URL | Still requires manual action. Claude can read the issue but you have to trigger it. |
| Use CLI with claude -p | Requires terminal access, not available on mobile/web-only workflows. |
| Manual copy-paste | Duplicates effort, easy to miss details from comments, no auto-linking. |

Priority

Medium - Would be very helpful

Feature Category

Other

Use Case Example

1. Solo developer workflow: Create issues for myself, assign to Claude, come back to review PRs
2. Team workflow: Product manager creates issues, assigns to Claude for initial implementation, developer reviews
3. Bug triage: Automatically have Claude attempt fixes for bugs labeled good-first-issue or claude-can-fix
4. Mobile workflow: Create issues from GitHub mobile app, Claude works on them, review PRs later

Additional Context

_No response_