Function _sanitize_agent_id

src/agent/transcript.py:99–115

Reject path-traversing agent_ids before we touch the filesystem. ``agent_id`` is internally generated by ``generate_task_id`` (CSPRNG base36), so this is defense-in-depth — a future caller passing a user-supplied id would otherwise be able to write to arbitrary paths via ``../../etc

(agent_id: str)

def _sanitize_agent_id(agent_id: str) -> str:
    """Reject path-traversing agent_ids before we touch the filesystem.

    ``agent_id`` is internally generated by ``generate_task_id`` (CSPRNG
    base36), so this is defense-in-depth — a future caller passing a
    user-supplied id would otherwise be able to write to arbitrary
    paths via ``../../etc/passwd``. Mirrors the chapter's symlink-attack
    rationale on TS Task.ts:96.
    """
    if not agent_id or not all(c.isalnum() or c in "_-" for c in agent_id):
        raise ValueError(
            f"invalid agent_id for transcript path: {agent_id!r} "
            "(allowed: alphanumeric + '_' + '-')"
        )
    if len(agent_id) > 64:
        raise ValueError(f"agent_id too long ({len(agent_id)} > 64 chars)")
    return agent_id


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