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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered; the description adds value by disclosing what the call surfaces (coverage counts and unassigned blocks), which matters because there is no output schema. It stops short of describing ordering or exact return shape, but that is a minor gap given the annotation coverage.

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 short sentences, front-loaded with the return content, then the workflow cue, then the exclusion. Every sentence carries distinct information with no repetition of the title or schema.

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 adequately enumerates what comes back (parts, explanations, block counts, unassigned blocks) and situates the tool in the show/simulate workflow. Slightly more on the shape of the report would make it fully self-sufficient, but an agent can call it confidently as written.

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?

There is a single required `design` parameter with 100% schema description coverage, including detailed nested descriptions for blocks, parts, and tests. The description implies which sub-fields matter (`parts` and `blocks[].part`) but adds no format or structure detail beyond the schema, 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?

States a specific verb ("List") and a precise resource: a design's parts, their explanations, per-part block counts, and blocks lacking a part. This is clearly differentiated from siblings like show and simulate, so an agent can identify the tool 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 the workflow ("Use it before show to make sure every block is explained") and names the exclusion plus the correct alternative ("Do not use it to test whether the machine works: use simulate"). Both the when and the when-not are stated with the sibling to use instead.

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