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

Annotations only flag destructiveHint=true; the description goes far beyond by explaining WHY and HOW: edits 'leaves everything you did not target untouched' and 'fails loudly rather than clobbering a doc somebody else is typing in', while body 'replaces the WHOLE document'. The archived true/false round-trip semantics are also disclosed.

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?

Dense but front-loaded: the primary recommendation (edits) leads, riskier modes follow, prerequisites and id provenance close it out. No filler sentences and every clause carries operational weight.

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 10-param mutation tool with no output schema, the description covers the decision logic, the safety model, the read-first prerequisite, and where ids come from. An agent has everything needed to call it correctly without further context.

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 80%, so the baseline is 3, but the description adds interpretation the schema lacks: the default-vs-last-resort ranking of edits/append/body and the gallery/archive round-trip behavior of archived. It maps none of the less-obvious params (visibility enum, approvalId) beyond what the schema already states.

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 ('Edit a Napkin doc') and then breaks down the distinct mutation modes (edits, append, body, retitle, visibility, archived). It clearly differentiates itself from sibling napkin_docs_get (read) and napkin_docs_list (ids), so an agent can place it without opening the 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?

Explicitly prescribes edits as 'the SAFEST option and the one to reach for by default', labels body a 'last resort', and states the prerequisite 'Read the doc with napkin_docs_get first'. This is textbook when/when-not/alternative guidance.

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