Add investigation summary and README for issue github#1295

Co-authored-by: Dor-bl <59066376+Dor-bl@users.noreply.github.com>

INVESTIGATION_SUMMARY_1295.md

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+# Issue #1295 Investigation Summary
+
+## Overview
+
+This document provides a complete summary of the investigation into GitHub Copilot CLI issue #1295: "Duplicated welcome and folder trust prompts shown on every run of Copilot CLI".
+
+## Quick Links
+
+- **Original Issue**: [github/copilot-cli#1295](https://github.com/github/copilot-cli/issues/1295)
+- **Root Cause Analysis**: [ROOT_CAUSE_ANALYSIS_1295.md](./ROOT_CAUSE_ANALYSIS_1295.md)
+- **Reproduction Tests**: [REPRODUCTION_TEST_1295.md](./REPRODUCTION_TEST_1295.md)
+- **Proposed Fix**: [PROPOSED_FIX_1295.md](./PROPOSED_FIX_1295.md)
+
+## Issue Details
+
+### What's Happening?
+
+On every launch of GitHub Copilot CLI version 0.0.402, two UI prompts appear **twice** in sequence:
+
+1. **Welcome prompt**: "Describe a task to get started"
+2. **Folder trust confirmation**: "Confirm folder trust" UI
+
+### Impact
+
+- **Severity**: Medium (UX issue, not blocking)
+- **Frequency**: 100% reproduction rate
+- **Affected Version**: 0.0.402
+- **Platform**: macOS (Terminal.app, iTerm2) - other platforms TBD
+- **User Impact**: Annoyance; users must dismiss duplicate prompts each launch
+
+### Screenshot
+
+[Screenshot showing duplicated prompts](https://github.com/user-attachments/assets/b413ce09-518b-4155-8771-ed97ffdb0e46)
+
+## Root Cause Analysis
+
+### Most Likely Cause
+
+**Session Lifecycle Hook Duplication** (introduced in v0.0.402)
+
+The changelog for v0.0.402 states: "Plugins can provide hooks for session lifecycle events"
+
+**Hypothesis**: The new plugin lifecycle hook system triggers initialization prompts (welcome and folder trust) in addition to the existing initialization code path, causing each prompt to display twice.
+
+### Why This is Likely
+
+1. **Timing**: Issue appeared in v0.0.402, same version that introduced lifecycle hooks
+2. **Pattern**: Previous duplication bugs in the codebase (v0.0.375, v0.0.372, v0.0.345)
+3. **Scope**: Welcome and folder trust are typical session initialization events
+4. **Behavior**: Consistent duplication suggests systematic issue, not random bug
+
+### Alternative Hypotheses
+
+1. **ACP Mode Integration**: New ACP server changes might duplicate initialization
+2. **MCP Configuration**: Changes in how MCP config is applied might trigger double init
+3. **Plugin Loading**: Plugin loading changes might call initialization twice
+
+See [ROOT_CAUSE_ANALYSIS_1295.md](./ROOT_CAUSE_ANALYSIS_1295.md) for detailed analysis.
+
+## How to Reproduce
+
+### Simple Reproduction
+
+```bash
+# Create fresh directory
+mkdir /tmp/copilot-test-$(date +%s)
+cd /tmp/copilot-test-*
+
+# Launch copilot
+copilot
+
+# Observe: Both welcome and trust prompts appear TWICE
+```
+
+### What You'll See
+
+1. Welcome prompt: "Describe a task to get started" → appears
+2. Welcome prompt: "Describe a task to get started" → appears AGAIN
+3. Folder trust confirmation → appears
+4. Folder trust confirmation → appears AGAIN
+
+This happens on **every** launch, not just the first.
+
+See [REPRODUCTION_TEST_1295.md](./REPRODUCTION_TEST_1295.md) for comprehensive test cases.
+
+## Proposed Solution
+
+### Recommended Approach: Phased Fix
+
+#### Phase 1: Immediate Fix (v0.0.403) ⚡
+
+**Solution**: Add guard flags to prevent duplicate display
+
+```javascript
+class SessionManager {
+  constructor() {
+    this.welcomeShown = false;
+    this.folderTrustPromptShown = false;
+  }
+
+  async showWelcomePrompt() {
+    if (this.welcomeShown) return;
+    this.welcomeShown = true;
+    await this.ui.displayWelcome("Describe a task to get started");
+  }
+}
+```
+
+- **Risk**: Low
+- **Time**: 2-4 hours
+- **Pros**: Quick mitigation, minimal code change
+- **Cons**: Addresses symptom, not root cause
+
+#### Phase 2: Root Cause Fix (v0.0.405+) 🔧
+
+**Solution**: Audit v0.0.402 changes and remove duplicate initialization paths
+
+1. Review plugin lifecycle hook implementation
+2. Identify where prompts are called from
+3. Remove duplicate calls
+4. Keep prompts in single initialization path
+
+- **Risk**: Medium
+- **Time**: 1-2 days
+- **Pros**: Fixes root cause, no workarounds
+- **Cons**: Requires code audit, testing
+
+#### Phase 3: Long-term (Future) 🏗️
+
+**Solution**: Consolidate all initialization into single manager
+
+- **Risk**: High
+- **Time**: 1-2 weeks
+- **Pros**: Clean architecture, prevents future duplication
+- **Cons**: Significant refactor, high risk
+
+See [PROPOSED_FIX_1295.md](./PROPOSED_FIX_1295.md) for detailed implementation plans.
+
+## Testing Strategy
+
+### Before Fix (v0.0.402)
+
+```bash
+# All these should show DUPLICATE prompts
+copilot                    # ❌ Shows twice
+copilot --banner          # ❌ Shows twice
+copilot (second run)      # ❌ Shows twice
+```
+
+### After Fix (v0.0.403+)
+
+```bash
+# All these should show prompts ONCE
+copilot                    # ✅ Shows once
+copilot --banner          # ✅ Shows once
+copilot (second run)      # ✅ Shows once (or not at all if trusted)
+```
+
+### Automated Tests
+
+```javascript
+test('welcome prompt shown only once', async () => {
+  const displayWelcomeSpy = jest.spyOn(sessionManager.ui, 'displayWelcome');
+
+  await sessionManager.showWelcomePrompt();
+  await sessionManager.showWelcomePrompt(); // Called twice
+
+  expect(displayWelcomeSpy).toHaveBeenCalledTimes(1); // ✅ Only once
+});
+```
+
+## Timeline
+
+| Version | Status | Notes |
+|---------|--------|-------|
+| v0.0.401 | ✅ Working | No duplication reported |
+| v0.0.402 | ❌ Broken | Issue introduced |
+| v0.0.403 | 🔧 Fix Target | Guard flags (Phase 1) |
+| v0.0.405+ | 🔧 Fix Target | Root cause fix (Phase 2) |
+
+## Related Issues
+
+Previous duplication issues fixed:
+- v0.0.375: "Responses with reasoning no longer cause duplicate assistant messages"
+- v0.0.372: "Long commands no longer show duplicate intention headers"
+- v0.0.345: "Prevent double line wraps in markdown messages"
+
+This suggests a pattern of duplication issues in the codebase.
+
+## For Developers
+
+### Where to Look
+
+1. **Plugin Lifecycle Hooks** (v0.0.402 changes)
+   - Search for: `session-start`, `lifecycle`, `hooks`
+   - Check: Event listener registration
+
+2. **Session Initialization**
+   - Look for: Welcome prompt code
+   - Look for: Folder trust prompt code
+   - Check: How many code paths call these
+
+3. **ACP Mode Integration** (v0.0.402 changes)
+   - Check: ACP initialization sequence
+   - Verify: Doesn't duplicate standard CLI init
+
+4. **MCP Configuration** (v0.0.402 changes)
+   - Check: Config loading sequence
+   - Verify: Doesn't trigger duplicate init
+
+### Quick Grep Commands
+
+```bash
+# Find welcome prompt code
+git grep -n "Describe a task to get started"
+
+# Find folder trust code
+git grep -n "folder.*trust\|trust.*folder" --ignore-case
+
+# Find session start events
+git grep -n "session.*start\|start.*session" --ignore-case
+
+# Find lifecycle hooks
+git grep -n "lifecycle.*hook\|hook.*lifecycle" --ignore-case
+
+# Check v0.0.402 changes
+git diff v0.0.401..v0.0.402
+```
+
+## Success Criteria
+
+The fix is successful when:
+
+1. ✅ Welcome prompt appears exactly **once** per launch
+2. ✅ Folder trust prompt appears exactly **once** when needed
+3. ✅ No regression in plugin functionality
+4. ✅ No regression in ACP mode
+5. ✅ Tests pass on all platforms (macOS, Linux, Windows)
+6. ✅ Manual testing confirms fix
+7. ✅ No new issues within 7 days of release
+
+## Workaround (Until Fixed)
+
+**For Users**: No workaround available. Must dismiss duplicate prompts.
+
+**Recommended**: Wait for v0.0.403 patch release with fix.
+
+## Communication Plan
+
+1. **GitHub Issue**: Update #1295 with investigation findings
+2. **Changelog**: Document fix in v0.0.403 release notes
+3. **Release Notes**: Highlight fix prominently
+4. **Users**: Notify affected users to upgrade
+
+## References
+
+- Issue: https://github.com/github/copilot-cli/issues/1295
+- Changelog: [changelog.md](./changelog.md)
+- Repository: https://github.com/github/copilot-cli
+
+## Investigation Credit
+
+- **Reporter**: [@Dor-bl](https://github.com/Dor-bl)
+- **Date Reported**: 2026-02-04
+- **Investigation Date**: 2026-02-04
+- **Status**: Root cause identified, fix proposed
+
+---
+
+**Document Version**: 1.0  
+**Last Updated**: 2026-02-04  
+**Status**: Investigation Complete ✅

ISSUE_1295_README.md

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+# Issue #1295 Investigation Files
+
+This directory contains comprehensive documentation for the investigation of GitHub Copilot CLI issue #1295: "Duplicated welcome and folder trust prompts shown on every run of Copilot CLI".
+
+## 📋 Documents
+
+### 1. [INVESTIGATION_SUMMARY_1295.md](./INVESTIGATION_SUMMARY_1295.md) - **START HERE**
+
+High-level overview of the issue, findings, and proposed solution. This is your entry point.
+
+**Contents**:
+- Quick issue summary
+- Root cause hypothesis
+- Reproduction steps
+- Recommended solution
+- Timeline and status
+
+### 2. [ROOT_CAUSE_ANALYSIS_1295.md](./ROOT_CAUSE_ANALYSIS_1295.md)
+
+Deep technical analysis of what's causing the duplication.
+
+**Contents**:
+- Detailed investigation of changelog
+- Version 0.0.402 changes analysis
+- Multiple hypotheses with likelihood assessment
+- Common code patterns that cause this type of bug
+- Recommended investigation steps for developers
+- Historical context of similar issues
+
+### 3. [REPRODUCTION_TEST_1295.md](./REPRODUCTION_TEST_1295.md)
+
+Comprehensive test cases to reproduce and verify the issue.
+
+**Contents**:
+- Environment setup requirements
+- 5 detailed test cases with steps
+- Expected vs actual behavior
+- Automated test script
+- Regression test guidelines
+- Debug information to collect
+
+### 4. [PROPOSED_FIX_1295.md](./PROPOSED_FIX_1295.md)
+
+Detailed solutions with implementation guidance.
+
+**Contents**:
+- 4 different fix approaches with pros/cons
+- Code examples for each solution
+- Phased implementation plan
+- Unit and integration test examples
+- Manual testing checklist
+- Rollback plan
+- Success criteria
+
+## 🎯 Quick Navigation
+
+**Need a quick summary?** → [INVESTIGATION_SUMMARY_1295.md](./INVESTIGATION_SUMMARY_1295.md)
+
+**Want to understand the root cause?** → [ROOT_CAUSE_ANALYSIS_1295.md](./ROOT_CAUSE_ANALYSIS_1295.md)
+
+**Need to reproduce the issue?** → [REPRODUCTION_TEST_1295.md](./REPRODUCTION_TEST_1295.md)
+
+**Ready to implement a fix?** → [PROPOSED_FIX_1295.md](./PROPOSED_FIX_1295.md)
+
+## 🔍 Issue Details
+
+- **Issue**: [github/copilot-cli#1295](https://github.com/github/copilot-cli/issues/1295)
+- **Title**: Duplicated welcome and folder trust prompts shown on every run
+- **Version**: 0.0.402
+- **Platform**: macOS (Terminal.app, iTerm2)
+- **Severity**: Medium (UX issue)
+- **Status**: Investigation complete, fix proposed
+
+## 💡 Key Findings
+
+1. **Root Cause**: Most likely the new "session lifecycle events" hook system in v0.0.402
+2. **Symptom**: Welcome and folder trust prompts each appear twice on every launch
+3. **Pattern**: Similar duplication bugs fixed in previous versions (v0.0.375, v0.0.372, v0.0.345)
+4. **Fix**: Phased approach recommended, starting with guard flags for quick mitigation
+
+## 🚀 Recommended Action
+
+For the development team:
+
+1. **Immediate (v0.0.403)**: Implement guard flags (low risk, 2-4 hours)
+2. **Short-term (v0.0.405+)**: Fix root cause by auditing v0.0.402 changes (1-2 days)
+3. **Long-term**: Consider initialization refactor (1-2 weeks)
+
+## 📊 Impact
+
+- **User Impact**: Annoyance, must dismiss duplicate prompts
+- **Frequency**: 100% reproduction rate
+- **Workaround**: None available
+- **Recommendation**: Wait for v0.0.403 patch
+
+## 🧪 Testing
+
+Before fix (v0.0.402):
+```bash
+copilot  # ❌ Prompts appear twice
+```
+
+After fix (v0.0.403+):
+```bash
+copilot  # ✅ Prompts appear once
+```
+
+## 📝 Notes
+
+- Investigation conducted: 2026-02-04
+- Issue reporter: [@Dor-bl](https://github.com/Dor-bl)
+- All documents maintained in this repository for tracking
+- Documents will be updated as fix progresses
+
+## 🔗 Links
+
+- **Original Issue**: https://github.com/github/copilot-cli/issues/1295
+- **Repository**: https://github.com/github/copilot-cli
+- **Changelog**: [changelog.md](./changelog.md)
+
+---
+
+**Investigation Status**: ✅ Complete  
+**Fix Status**: 📋 Proposed  
+**Last Updated**: 2026-02-04