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

Annotations already carry readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds the key non-obvious behavior the schema cannot convey: the tool returns a rendered image (layout, arrows, strokes, sticky notes) rather than structured data, plus the required citation format. It omits render size/latency limits.

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?

Two tight sentences, with the core capability and the 'SEE' contrast front-loaded before the usage and citation guidance. Slightly long due to the embed syntax, but every clause is actionable and nothing is redundant.

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?

No output schema exists, and the description compensates by explaining exactly what comes back (a rendered image of the drawing). Combined with when-to-use and citation guidance, and with safety covered by annotations, an agent has everything needed to call this correctly.

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?

With 2 parameters at 100% schema description coverage, the schema already fully documents boardId and workspace (including the personal-token workspace requirement). The description alludes to boardId via the [[board:ID]] citation example but adds no new parameter semantics, so the baseline of 3 is appropriate.

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?

The description states a precise verb (renders the board to an image and returns it) and resource (sketch board), and explicitly distinguishes itself from the data-only sibling by saying 'not just data about it.' An agent can tell this apart from napkin_boards_get without opening either 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?

It gives a clear selection rule: 'Use this before answering any question about a sketch's contents,' and adds the citation convention ([[board:ID]]) for replies. It stops short of naming the alternative tool (napkin_boards_get) or stating exclusions, so it is clear context rather than fully explicit routing.

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