Tool-Schnittstellen fürs Programmieren (Read, Edit, Bash)

Welche Tools benötigt ein Code-Agent?

read_file

def read_file(path: str, start_line: int = 0, end_line: int | None = None) -> str:
    with open(path) as f:
        lines = f.readlines()
    return ''.join(lines[start_line:end_line])

# --- demo ---
with open('demo_source.py', 'w', encoding='utf-8') as f:
    f.write('line0\nline1\nline2\nline3\nline4\n')

snippet = read_file('demo_source.py', start_line=1, end_line=3)
print('Lines 1-2 of demo_source.py:')
print(snippet)

Das Lesen von Zeilenbereichen spart Tokens

edit_file (String-Ersetzung)

def edit_file(path: str, old_string: str, new_string: str):
    contents = read_file(path)
    occurrences = contents.count(old_string)
    if occurrences == 0:
        raise ValueError('old_string not found')
    if occurrences > 1:
        raise ValueError('old_string is not unique')
    contents = contents.replace(old_string, new_string)
    with open(path, 'w') as f:
        f.write(contents)

Warum String-Ersetzung statt Diffs?

write_file

def write_file(path: str, content: str):
    os.makedirs(os.path.dirname(path), exist_ok=True)
    with open(path, 'w') as f:
        f.write(content)

bash

def bash(command: str, timeout: int = 60) -> dict:
    import subprocess
    try:
        result = subprocess.run(command, shell=True, capture_output=True, text=True, timeout=timeout)
        return {'stdout': result.stdout[-5000:], 'stderr': result.stderr[-5000:], 'exit_code': result.returncode}
    except subprocess.TimeoutExpired:
        return {'error': 'timeout', 'exit_code': -1}

# --- demo ---
result = bash("echo hello from the sandboxed shell")
print(f"exit_code={result['exit_code']}")
print(f"stdout={result['stdout'].strip()!r}")

Das Bash-Tool in einer Sandbox ausführen

Lange Ausgaben kürzen

stderr = 'error line\n' * 1000

if len(stderr) > 5000:
    stderr = '...[truncated]...' + stderr[-5000:]

print(f'Truncated stderr length: {len(stderr)}')

search / grep

def grep(pattern: str, path: str = '.', file_glob: str = '**/*') -> list[str]:
    matches = []
    for f in glob(file_glob, recursive=True):
        for i, line in enumerate(open(f)):
            if re.search(pattern, line):
                matches.append(f'{f}:{i+1}: {line.rstrip()}')
    return matches[:50]

list_files

def list_files(path: str = '.') -> list[str]:
    return [p for p in glob(f'{path}/**', recursive=True) if os.path.isfile(p)][:200]

Optional: AST-Tools

def find_function(name: str, path: str):
    tree = ast.parse(open(path).read())
    for node in ast.walk(tree):
        if isinstance(node, ast.FunctionDef) and node.name == name:
            return ast.unparse(node)

Tool-Beschreibungen sind hier am wichtigsten

description='Edit a file by replacing a unique string. The old_string MUST appear exactly once in the file. Reads the file first to validate. Use this for any code change in an existing file.'

Das ist der gesamte Werkzeugsatz

Bearbeitungsmuster

Zusammenfassung