gemini-use-claude-acp

Gemini → Claude via ACP

Spawn a Claude Code ACP adapter subprocess, send a prompt, stream the response to stdout, and terminate cleanly. No persistent session — one prompt, one response.

When to use

• The task requires complex multi-step agentic coding with MCP tool access
• You want Claude's reasoning on a specific problem
• The user says "ask Claude", "use Claude for this", etc.
• You want a second opinion from a different model

Setup (first use only)

cd ~/.gemini/skills/gemini-use-claude-acp/scripts
pnpm install

This installs @agentclientprotocol/sdk into the local node_modules/. Subsequent runs skip this step.

Usage

CLAUDE_MODEL=claude-sonnet-4-6 \
TARGET_CWD=/path/to/project \
node ~/.gemini/skills/gemini-use-claude-acp/scripts/claude-delegate.mjs \
  "Refactor the auth module to use JWT tokens. The code is in src/auth/."

The response streams to stdout as Claude generates it. Capture it:

response=$(node ~/.gemini/skills/gemini-use-claude-acp/scripts/claude-delegate.mjs "your prompt")

Environment variables

Variable	Default	Description
CLAUDE_MODEL	claude-sonnet-4-6	Model to use (applied via ACP unstable_setSessionModel)
TARGET_CWD	current working dir	Working directory passed to the Claude session

How it works

1. Spawns pnpm dlx @zed-industries/claude-code-acp with:
   • CLAUDE_CODE_SKIP_PERMISSIONS=1 — auto-approves all tool calls
   • TERM=dumb — prevents ANSI escape sequences in output
   • CLAUDECODE unset — prevents the adapter refusing to start inside another Claude session
   • ~/.local/bin prepended to PATH — ensures the claude binary is found
2. Connects via @agentclientprotocol/sdk's ClientSideConnection + ndJsonStream
3. Sends initialize → newSession → unstable_setSessionModel → prompt over ACP
4. Streams agent_message_chunk deltas to stdout as they arrive
5. Terminates the subprocess once the prompt response completes

Prompt construction tips

• Include all relevant context in the prompt string — this is a fresh session with no prior history
• Reference files by absolute path if you want Claude to read/edit them
• Keep prompts focused: one clear task per invocation
• Claude can use its MCP tools (filesystem, shell, etc.) during the session

Error handling

If the script exits non-zero, check stderr for:

• pnpm dlx download failures (network, auth)
• Claude auth errors — ensure claude CLI is authenticated
• CLAUDECODE environment variable being set (indicates you're running inside Claude Code; the adapter refuses to nest)
• ACP initialization failures

The script does not retry — surface the error to the user and suggest re-running after fixing the root cause.