Function Compute:Use Claude Code Sandbox

Clone a Repository and Execute a Task

sandbox.git.clone(
    "https://github.com/your-org/your-repo.git",
    path="/home/user/repo",
    username="x-access-token",
    password="<your-github-token>",
    depth=1,
)

result = sandbox.commands.run(
    'cd /home/user/repo && claude --dangerously-skip-permissions < /dev/null '
    '-p "Add error handling to all API endpoints"',
    on_stdout=lambda data: print(data, end=""),
    timeout=0,
)

diff = sandbox.commands.run("cd /home/user/repo && git diff")
print(diff.stdout)

Get Structured JSON Output

import json

result = sandbox.commands.run(
    'claude --dangerously-skip-permissions --output-format json < /dev/null '
    '-p "List all files and describe each" 2>&1',
    timeout=0,
)

for line in reversed(result.stdout.strip().split("\n")):
    if line.startswith("{"):
        response = json.loads(line)
        break
else:
    raise RuntimeError("no JSON in output")

print(response.get("result") or response)

Streaming JSONL Output

import json

def handle_event(data):
    for line in data.strip().split("\n"):
        if line.startswith("{"):
            event = json.loads(line)
            if event["type"] == "assistant":
                usage = event.get("message", {}).get("usage", {})
                print(f"[assistant] tokens: {usage.get('output_tokens')}")
            elif event["type"] == "result":
                print(f"[done] {event['subtype']} in {event['duration_ms']}ms")

sandbox.commands.run(
    'claude --dangerously-skip-permissions --verbose --output-format stream-json < /dev/null '
    '-p "Find and fix all TODO comments" 2>&1',
    on_stdout=handle_event,
    timeout=0,
)

Resume a Session

import json

initial = sandbox.commands.run(
    'claude --dangerously-skip-permissions --output-format json < /dev/null '
    '-p "Analyze the codebase and create a refactoring plan" 2>&1',
    timeout=0,
)

for line in reversed(initial.stdout.strip().split("\n")):
    if line.startswith("{"):
        session_id = json.loads(line)["session_id"]
        break
else:
    raise RuntimeError("no session_id in output")

sandbox.commands.run(
    f'claude --dangerously-skip-permissions --resume {session_id} < /dev/null '
    f'-p "Now implement step 1 of the plan"',
    on_stdout=lambda data: print(data, end=""),
    timeout=0,
)

Custom System Prompt

sandbox.files.write("/home/user/repo/CLAUDE.md", """
You are working on a Go microservice.
Always use structured logging with slog.
Follow the project's error handling conventions in pkg/errors.
""")

sandbox.commands.run(
    'cd /home/user/repo && claude --dangerously-skip-permissions < /dev/null '
    '-p "Add a /healthz endpoint"',
    timeout=0,
)

Connect MCP Tools

Claude Code natively supports MCP. You can manually register MCP Servers via claude mcp add; the sandbox has outbound network access.

stdio local process (recommended):

sandbox.commands.run(
    "claude mcp add --transport stdio fs -- "
    "npx -y @modelcontextprotocol/server-filesystem /home/user",
    timeout=180,
)

result = sandbox.commands.run(
    'claude --dangerously-skip-permissions < /dev/null '
    '-p "Use the fs MCP tool to list /home/user and summarize top-level entries."',
    timeout=0,
)

HTTP remote Server:

sandbox.commands.run(
    "claude mcp add --transport http deepwiki https://mcp.deepwiki.com/mcp",
)

result = sandbox.commands.run(
    'claude --dangerously-skip-permissions < /dev/null '
    '-p "Use deepwiki MCP: what tools are available?"',
    timeout=0,
)

For MCP support and limitations, see “MCP and Skill Conventions” in Claude Code Template.

Extend Capabilities with Skills

The image does not preload custom Skills. A Skill is a Claude Code filesystem convention: place a directory that contains SKILL.md. For details, see Extend Claude with skills.

How to trigger: explicitly call /skill-name in the -p prompt, or describe a matching task so the model loads it automatically. Claude Code also ships bundled skills such as /debug and /code-review that require no extra installation.

Write a personal Skill at runtime:

sandbox.files.write(
    "/home/user/.claude/skills/summarize-changes/SKILL.md",
    """---
description: Summarizes uncommitted changes and flags risks. Use when reviewing diffs or writing commit messages.
---

## Instructions
1. Run `git diff HEAD` and summarize changes in 2–3 bullets.
2. List risks such as missing error handling or hardcoded values.
3. If the diff is empty, say there are no uncommitted changes.
""",
)

result = sandbox.commands.run(
    'claude --dangerously-skip-permissions < /dev/null '
    '-p "/summarize-changes"',
    timeout=0,
)
print(result.stdout)

Project Skill (takes effect with the repository / working directory):

sandbox.files.write(
    "/home/user/repo/.claude/skills/api-conventions/SKILL.md",
    """---
description: API design conventions for this codebase. Use when adding or changing HTTP endpoints.
---

When writing API endpoints:
- Use RESTful naming
- Return consistent error formats
- Include request validation
""",
)

sandbox.commands.run(
    'cd /home/user/repo && claude --dangerously-skip-permissions < /dev/null '
    '-p "/api-conventions Add a /healthz endpoint"',
    timeout=0,
)

Upload a multi-file Skill directory from your local machine:

If a Skill includes accompanying files such as scripts/ or references/, use files.write_files to write them in one batch instead of calling files.write for each file:

from pathlib import Path

def upload_skill_dir(sandbox, local_dir: str, remote_root: str) -> None:
    local = Path(local_dir).resolve()
    entries = []
    for path in local.rglob("*"):
        if path.is_file():
            rel = path.relative_to(local).as_posix()
            entries.append({
                "path": f"{remote_root.rstrip('/')}/{rel}",
                "data": path.read_bytes(),
            })
    sandbox.files.write_files(entries)

# Example local directory layout:
# ./my-skills/echo-marker/SKILL.md
# ./my-skills/echo-marker/scripts/marker.txt
upload_skill_dir(
    sandbox,
    "./my-skills/echo-marker",
    "/home/user/.claude/skills/echo-marker",
)

result = sandbox.commands.run(
    'claude --dangerously-skip-permissions < /dev/null '
    '-p "/echo-marker"',
    timeout=0,
)
print(result.stdout)

For project scope, set remote_root to /home/user/repo/.claude/skills/<name> instead. You can also clone a repository that already contains .claude/skills/ and use it directly.

About Template.copy: Prefilling files with .copy("local-dir", "/home/user/.claude/skills/...") during Template.build is not supported yet. Use the runtime files.write / files.write_files approaches above for custom Skills.