Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only declare read-only safety, but the description adds real behavioral detail: the exact return fields (id, kind, position, size, text) and the limitation that pen strokes come back as a point count rather than points. It omits things like result size limits or error behavior, so it falls short of a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tightly packed sentences, front-loaded with the purpose and return shape, then the pen-stroke caveat and sibling routing. No wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description compensates by describing the returned shape fields and the pen-stroke truncation; read-only safety is covered by annotations. Nothing needed to call it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so both boardId and workspace are already documented, and the description's note that ids come from napkin_boards_list duplicates the schema text. Baseline 3 applies since the description adds no new parameter meaning.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ("Returns a board's shapes as data") and enumerates the returned fields, immediately distinguishing it from napkin_boards_view (visual) and napkin_draw (edits). An agent can tell it apart from every sibling without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit routing: use this to target a shape for change/removal via napkin_draw, use napkin_boards_view for appearance, and get board ids from napkin_boards_list. Both the when and the when-not alternatives are named.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.