rohitg00/ai-engineering-from-scratch · error · ValueError

unknown hook topic: {topic}

Error message

unknown hook topic: {topic}

What it means

Error "unknown hook topic: {topic}" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/19-capstone-projects/20-agent-harness-loop-contract/code/main.py:126

    state: State
    payload: dict


@dataclass
class SessionResult:
    state: State
    reason: str
    steps: list[Step]
    events: list[Event]


class HookRegistry:
    def __init__(self) -> None:
        self._subs: dict[str, list[Callable[[dict], Any]]] = {t: [] for t in HOOK_TOPICS}

    def on(self, topic: str, fn: Callable[[dict], Any]) -> None:
        if topic not in self._subs:
            raise ValueError(f"unknown hook topic: {topic}")
        self._subs[topic].append(fn)

    def fire(self, topic: str, payload: dict) -> list[Any]:
        results = []
        for fn in self._subs[topic]:
            results.append(fn(payload))
        return results


Planner = Callable[[str, list[Step]], list[Step]]


def _default_planner(goal: str, history: list[Step]) -> list[Step]:
    """Deterministic stand-in planner. Returns a fixed three-step plan."""
    if history:
        return []
    return [
        Step(id=1, description=f"interpret goal: {goal}", requires_tool=False),

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/19-capstone-projects/20-agent-harness-loop-contract/code/main.py:126 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of rohitg00/ai-engineering-from-scratch@39ea8a1c6d (2026-08-26). Data as JSON: /api/errors/1a4a4ea7f86791c3. Report an issue: GitHub.