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

Annotations already cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false). The description adds genuinely non-structured behavior: the post-creation citation contract ([[doc:ID]] on its own line, renders as a card, never [[board:ID]]). It does not mention auth/workspace constraints, but the schema carries those, so the remaining gap is minor.

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 tight sentences, front-loaded with the artifact type, then the disambiguation, then the citation rule. Every sentence carries decision-relevant information; there is no filler.

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?

For a creation tool with no output schema, the description covers the type, the optional inputs, and the required follow-up citation format — enough to call it correctly. It stops short of stating the returned identifier shape explicitly (the [[doc:ID]] hint implies it), a small remaining gap.

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 coverage is 67%. The body parameter is richly documented in the schema itself (single-long-line markdown guidance), and the description only says it is optional. The title parameter has no schema description at all, and the description only adds 'optionally pass a title.' Marginal added meaning over structured fields.

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 ('Create a Napkin doc — a markdown DOCUMENT') and immediately disambiguates from the two most confusable siblings by name: napkin_boards_create and napkin_deck_write. An agent can route correctly without opening any 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?

Gives an explicit usage condition ('Use for drafts the user asked you to start') and explicit alternatives for the neighboring artifact types (drawing canvas -> napkin_boards_create, slides -> napkin_deck_write). This is when-to-use plus when-not, which is the top of the scale.

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