Purpose

Note: This is a documentation/guide skill. It provides instructions for invoking external AI CLIs using Claude Code's native Task agents. Read this skill to learn the patterns, then use the Task tool manually with subagent_type="general-purpose".

Invoke external AI coding CLIs using Claude Code's native Task agents. This is the primary mode for multi-provider orchestration, with fork-terminal as fallback for authentication.

Variables

Variable	Default	Description
DEFAULT_AGENT	gemini	Agent to use when not explicitly specified
ENABLED_CODEX	true	Enable OpenAI Codex via native agent
ENABLED_GEMINI	true	Enable Google Gemini via native agent
ENABLED_CURSOR	true	Enable Cursor Agent via native agent
RUN_IN_BACKGROUND	true	Run agents asynchronously
PARALLEL_EXECUTION	true	Launch multiple agents in parallel
AUTO_RETRY_ON_AUTH	true	Auto-retry with fork-terminal on auth failure
READ_ONLY_MODE	true	Prevent agents from modifying codebase
CLEANUP_AGENT_FILES	true	Clean up any files agents write to repo

Prerequisites

CLI Permissions for Subagents

Native Task agents (subagents) require pre-approved permissions to execute CLI commands. Without these, the Bash tool will be "auto-denied (prompts unavailable)".

Required in .claude/settings.json:

{
  "permissions": {
    "allow": [
      "Bash(codex:*)",
      "Bash(gemini:*)",
      "Bash(cursor-agent:*)"
    ]
  }
}

Setup: Run /ai-dev-kit:setup to configure permissions automatically.

Manual: Add permissions via Claude Code settings or approve when prompted.

Fallback: If permissions are denied, use fork-terminal for interactive execution.

Instructions

MANDATORY - You MUST follow the Workflow steps below in order. Do not skip steps.

Agent Selection

1. Explicit request: If user specifies an agent, use that agent
2. No agent specified: Use DEFAULT_AGENT
3. Check enabled: Verify the ENABLED_* flag is true before proceeding

Reading Cookbooks

• Based on the selected agent, read the appropriate cookbook from ../spawn/agent/cookbook/
• You MUST run --help on the CLI before constructing the command
• Follow cookbook instructions for non-interactive flags

Red Flags - STOP and follow Cookbook

If you're about to:

• Launch a native agent without reading the cookbook first
• Execute a CLI command without running --help
• Skip steps because "this is simple"
• Use interactive flags in non-interactive context

STOP -> Read the appropriate cookbook file -> Check --help -> Then proceed

Critical: Native agents cannot handle TTY input. Always use non-interactive flags:

• Codex: codex exec --full-auto
• Cursor: cursor-agent --force -p
• Gemini: Use positional prompt (not -i)

Workflow

MANDATORY CHECKPOINTS - Verify each before proceeding:

1. [ ] Understand the user's request
2. [ ] SELECT AGENT(S): Determine which agent(s) to use
3. [ ] READ: Cookbook for each selected agent from ../spawn/agent/cookbook/
4. [ ] RUN HELP: Execute <cli> --help to verify available flags
5. [ ] CONSTRUCT COMMAND: Build non-interactive command per cookbook
6. [ ] CHECKPOINT: Confirm cookbook instructions were followed
7. [ ] Execute via Task tool with run_in_background: true
8. [ ] Collect results via TaskOutput
9. [ ] ON AUTH FAILURE: Trigger fork-terminal fallback (see Auth Recovery)

Read-Only vs Write Mode

Default: READ_ONLY_MODE = true

When READ_ONLY_MODE is enabled, agents should only analyze and report - not modify files.

Read-Only Flags by Provider

Provider	Read-Only Command	Write Mode Command
Codex	codex exec --sandbox read-only --full-auto	codex exec --sandbox workspace-write --full-auto
Gemini	gemini --sandbox --yolo	gemini --yolo
Cursor	cursor-agent -p (no --force)	cursor-agent --force -p

Prompting for Read-Only

Always include in prompt when READ_ONLY_MODE is true:

"Do NOT modify any files. Only analyze and report findings.
If you would normally write to a file, instead return the content in your response."

Worktree Isolation (Recommended for Write Mode)

When agents need write access, use git worktrees for true isolation:

# Create isolated worktree for agent work
git worktree add /tmp/agent-workspace-<id> -b agent/<provider>-<task>

# Run agent in worktree
cd /tmp/agent-workspace-<id>
<agent-command>

# Review changes
git diff

# If approved, merge back
git checkout main
git merge agent/<provider>-<task>

# Cleanup
git worktree remove /tmp/agent-workspace-<id>
git branch -d agent/<provider>-<task>

Benefits of Worktree Isolation

• Full write access: Agents can make any changes freely
• Selective merge: Only merge approved changes
• No cleanup needed: Discard worktree to reject changes
• Parallel agents: Multiple worktrees for parallel providers
• Branch history: Changes are tracked in git

When to Use Worktrees

Scenario	Approach
Analysis/review only	READ_ONLY_MODE + CLI flags
Single file edit	Write mode with cleanup
Multi-file refactor	Worktree isolation
Experimental changes	Worktree (easy to discard)
Parallel agent work	Separate worktrees per agent

Cleanup Protocol

When CLEANUP_AGENT_FILES is true (default) and NOT using worktrees:

1. Check for new files in the working directory
2. Preserve valuable content by reading files before deletion
3. Delete agent-created files (e.g., *_REVIEW_OUTPUT.md, *_analysis.json)
4. Log cleanup actions for audit trail

# Cleanup pattern
cleanup_patterns = [
    "*_REVIEW_OUTPUT.md",
    "*_analysis.json",
    "*_findings.md",
    "agent_output_*.txt"
]

Cookbook

Codex (OpenAI)

• IF: User requests Codex/OpenAI and 'ENABLED_CODEX' is true
• THEN: Read ../spawn/agent/cookbook/codex-cli.md
• Native command pattern (read-only):

  codex exec --sandbox read-only --full-auto --model gpt-5.2-codex "<prompt>"

• Native command pattern (write mode):

  codex exec --sandbox workspace-write --full-auto --model gpt-5.2-codex "<prompt>"

• Auth failure pattern: "Please log in", "authentication required"
• Login command: codex login

Gemini (Google)

• IF: User requests Gemini/Google and 'ENABLED_GEMINI' is true
• THEN: Read ../spawn/agent/cookbook/gemini-cli.md
• Native command pattern (read-only):

  gemini --model gemini-3-pro --sandbox --yolo "<prompt>"

• Native command pattern (write mode):

  gemini --model gemini-3-pro --yolo "<prompt>"

• Auth failure pattern: "Please authenticate", "run gemini auth"
• Login command: gemini auth login

Cursor

• IF: User requests Cursor and 'ENABLED_CURSOR' is true
• THEN: Read ../spawn/agent/cookbook/cursor-cli.md
• Native command pattern (read-only - prompts for approval):

  cursor-agent --model claude-sonnet-4.5 -p "<prompt>"

• Native command pattern (write mode - auto-approves):

  cursor-agent --model claude-sonnet-4.5 --force -p "<prompt>"

• Auth failure pattern: "Please log in", browser popup needed
• Login command: cursor-agent login

Auth Recovery

When a native agent reports an authentication failure:

1. Detect: Check output for auth failure patterns
2. Fork for login: Use fork-terminal with login command
3. Wait: Monitor for terminal close
4. Retry: Re-launch native agent

# Auth recovery flow
def handle_auth_failure(provider: str, original_prompt: str):
    login_commands = {
        "codex": "codex login",
        "gemini": "gemini auth login",
        "cursor": "cursor-agent login"
    }

    # Fork terminal for interactive login
    fork_terminal(login_commands[provider], wait_for_close=True)

    # After terminal closes, retry native invocation
    return invoke_native(provider, original_prompt)

Parallel Invocation

To invoke multiple agents in parallel, use a single message with multiple Task tool calls:

# Launch Gemini, Codex, and Cursor in parallel
Task(subagent_type="general-purpose", run_in_background=true, prompt="gemini ...")
Task(subagent_type="general-purpose", run_in_background=true, prompt="codex ...")
Task(subagent_type="general-purpose", run_in_background=true, prompt="cursor ...")

Collect results:

TaskOutput(task_id="...", block=false)  # Check progress
TaskOutput(task_id="...", block=true)   # Wait for completion

Result Collection

Native agents return results via TaskOutput tool:

Parameter	Value	Behavior
block=false	Check status	Non-blocking progress check
block=true	Wait for completion	Blocks until agent finishes
timeout	milliseconds	Max wait time before timeout

Example Collection Pattern

# Check progress (non-blocking)
TaskOutput(task_id="abc123", block=false)

# Wait for completion (blocking)
TaskOutput(task_id="abc123", block=true, timeout=120000)

Comparison: Native vs Fork-Terminal

Aspect	Native Task Agent	Fork-Terminal
Parallel execution	Excellent	Good
Result collection	TaskOutput (clean)	File parsing
TTY/Interactive	NO	YES
Auth handling	Reports failure	Interactive login
Resume capability	YES (agent ID)	NO

Use Native when:

• Automating multi-provider tasks
• Parallel execution needed
• Clean result collection required

Use Fork-Terminal when:

• Interactive mode needed
• Browser-based auth required
• Real-time streaming output needed