Claude Code Agent

When to use

Use this skill when the research task requires:

• Writing and running non-trivial code that needs iteration to get right
• Analysing a codebase (clone a repo, understand its structure, answer questions about it)
• Generating a working implementation of something described in a paper or spec
• Running experiments where the code needs to adapt based on intermediate results
• Any coding task where a single generate_code + execute cycle would not be enough

Do NOT use for trivial one-shot scripts — code_execution alone is faster and sufficient.

How to execute

Step 1 — Check which backend is available

Always run this check first:

import os, subprocess

has_anthropic_key = bool(os.environ.get("ANTHROPIC_API_KEY"))
claude_available = False
if has_anthropic_key:
    r = subprocess.run(["claude", "--version"], capture_output=True, text=True)
    claude_available = r.returncode == 0

print("backend:", "claude_code" if claude_available else "gemini_fallback")

Execute this with execute(). Then follow the matching path below.

Path A — Claude Code (when claude_available is True)

claude -p runs non-interactively and exits when done.

import subprocess

task = """
<describe the coding task in full detail>
Output the result as plain text or JSON.
"""

result = subprocess.run(
    ["claude", "-p", task],
    capture_output=True,
    text=True,
    timeout=300,
)
print("exit:", result.returncode)
print(result.stdout)
if result.stderr:
    print("stderr:", result.stderr[:2000])

If the output is incomplete, make a follow-up call with the prior output as context:

result2 = subprocess.run(
    ["claude", "-p", f"Previous output:\n{result.stdout}\n\nContinue: <remaining task>"],
    capture_output=True, text=True, timeout=300,
)
print(result2.stdout)

Path B — Gemini fallback (when claude_available is False)

Use generate_code to produce the implementation, then execute to run it. Iterate up to 3 times.

Iteration pattern:

1. Call generate_code("full task description") — returns working Python
2. Call execute(code) — run it, read stdout/stderr
3. If it fails or output is wrong: call generate_code("fix this: <error> in this code: <code>") and execute again
4. After 3 iterations, accept the best result and record what remains incomplete

For codebase analysis without Claude Code:

import subprocess, tempfile

with tempfile.TemporaryDirectory() as tmpdir:
    subprocess.run(["git", "clone", "--depth=1", repo_url, tmpdir], check=True, timeout=120)
    # Then use generate_code + execute to analyse the cloned repo

Output contract

Include in proof:

• backend_used: "claude_code" or "gemini_fallback"
• task_given: the coding task description
• output: the final result (stdout or generated artefact)
• iterations: number of attempts made
• exit_code (Claude Code path): 0 = success
• error_output (if any): stderr or exception text

List produced files in artefacts.

Quality bar

• Always run the Step 1 backend check — do not assume which is available
• Claude Code path: capture both stdout and stderr; stderr shows tool use logs
• Gemini fallback path: do not exceed 3 iterations — accept partial results and note gaps in proof
• Never pass secrets or credentials in the task string
• Set timeout ≥ 120s on all subprocess calls

Pairs with

• web_browse — fetch specs or docs first, then pass them to the coding agent
• dataset_inspection — inspect a dataset's schema, then delegate cleaning/analysis here
• code_execution — this skill IS the advanced form of code_execution; use plain code_execution for simple one-shot scripts

Source: ai-agents-for-humans/slow-ai — distributed by TomeVault.