Add autonomous agent mode with ReAct-style iterative execution

[Copilot]

Transforms Loz from single-shot command execution to autonomous multi-step task completion. Agent iterates through plan → execute → feedback cycles until task complete or limits reached.

Architecture

Agent Loop (src/agent/loop.ts)

• ReAct pattern: LLM generates action → execute → add result to context → repeat
• Step limits (default: 20), timeout per command (30s), repeated failure detection (3x)

Protocol (src/agent/protocol.ts)

• Strict JSON: {"action": "run"|"edit"|"done", ...}
• Run: execute shell commands
• Edit: apply unified diff patches
• Done: complete with summary

Safety (src/agent/safety.ts)

• Sandbox mode: restricts to working directory (default on)
• Network isolation: requires --enable-network flag
• Command validation: allowlist + denylist, blocks dangerous ops
• Resource limits: 10KB output truncation, 30s timeouts

Context Management (src/agent/memory.ts)

• Maintains conversation history with intelligent truncation
• Groups actions/results by step for LLM context

CLI Usage

loz agent "Fix failing tests"
loz agent -v --max-steps 30 "Add input validation to auth"
loz agent --enable-network "Update dependencies and fix breaking changes"

Flags: --max-steps, --verbose, --sandbox, --enable-network

Example Session

$ loz agent "Fix TypeError in validateUser"

🤖 Starting agent mode...
📋 Goal: Fix TypeError in validateUser

[Step 1] Running: npm test
❌ TypeError: Cannot read property 'name' of undefined at validateUser

[Step 2] Editing: src/auth.ts
✅ Applied null check patch

[Step 3] Running: npm test  
✅ All 15 tests passing

📊 Completed in 3 steps

Testing

54 new tests covering protocol parsing, safety validation, context management, and integration. Zero security vulnerabilities (CodeQL scan clean).

Backward Compatibility

Existing commands (loz, loz "prompt", loz commit) unchanged. Agent mode is opt-in via agent subcommand.

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💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.