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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), so the bar is lower. The description adds real value beyond them by disclosing the return content ('alerts, applicable correctifs and the coverage per level') and cost/auth context ('Free, no key'). It does not explain the appliquer/revalider behaviour visible in the schema.

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 dense sentences, front-loaded with the WHEN trigger, then the rules, then the return and cost. Nothing is redundant, though the rule enumeration is packed tightly into a single sentence.

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 annotations present, no output schema, and a fully documented (if shared and oversized) input schema, the description covers purpose, trigger, return shape and cost adequately. It could note which scene fields are relevant to the check, but overall an agent has enough to call it 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?

Schema description coverage is 100% across all 14 scene parameters, so the schema already carries parameter meaning and the baseline is 3. The description adds no parameter-level guidance (e.g. which fields the completeness check actually consumes), leaving the schema to do all the work.

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 specific check (drawing-set completeness) and enumerates exactly what it verifies: one plan per level, stair access to each upper floor, guardrails per NF P01-012. It explicitly distinguishes itself from the sibling cao_verifier, which 'already includes it', so an agent can tell the two apart 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?

'WHEN you need the drawing-set completeness check alone' gives the selecting condition, and naming cao_verifier as the tool that already bundles this check effectively points to the alternative. It stops short of an explicit when-not (e.g. 'do not use if you also need electrical/structure checks'), but the routing signal is clear.

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