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

title and body must be strings

Error message

title and body must be strings

What it means

Error "title and body must be strings" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/13-tools-and-protocols/07-building-an-mcp-server/code/main.py:215

    if not isinstance(query, str) or not query:
        raise ValueError("query must be a non-empty string")
    limit = arguments.get("limit", 10)
    if not isinstance(limit, int) or not 1 <= limit <= 50:
        raise ValueError("limit must be an integer from 1 through 50")
    needle = query.lower()
    hits = [
        {"id": note_id, "title": note["title"]}
        for note_id, note in sorted(NOTES.items())
        if needle in note["title"].lower() or needle in note["body"].lower()
    ]
    return [{"type": "text", "text": json.dumps(hits[:limit], sort_keys=True)}]


def exec_notes_create(arguments: dict[str, Any]) -> list[dict[str, Any]]:
    title = arguments.get("title")
    body = arguments.get("body")
    if not isinstance(title, str) or not isinstance(body, str):
        raise ValueError("title and body must be strings")
    note_id = f"note-{uuid.uuid4().hex[:6]}"
    NOTES[note_id] = {"title": title, "body": body, "tag": str(arguments.get("tag", ""))}
    return [
        {"type": "text", "text": f"Created {note_id}"},
        {
            "type": "resource",
            "resource": {"uri": f"notes://{note_id}", "text": body},
        },
    ]


TOOL_EXECUTORS: dict[str, Callable[[dict[str, Any]], list[dict[str, Any]]]] = {
    "notes_create": exec_notes_create,
    "notes_list": exec_notes_list,
    "notes_search": exec_notes_search,
}

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/13-tools-and-protocols/07-building-an-mcp-server/code/main.py:215 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/32279e520f4ae281. Report an issue: GitHub.