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

Annotations already establish readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds what is measured and what the gap list represents, which is useful behavioral context. However, it omits the async-job behavior (the job can come back 'running' and must be polled with get_board_job) — that disclosure lives only in the wait_s schema field, not in the description.

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?

It is a single dense sentence with two lengthy em-dash spans. The metric list is front-loaded and useful, but phrasing like 'the numbers a designer judges routed copper by' and 'not yet human-grade' is editorial rather than informative, adding length without adding precision.

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 carries the return-shape burden and does a reasonable job by naming the metrics, the per-net reference bands, and the gap_to_designers list. A read-only analysis tool of this kind is largely covered, though the job-status/polling path remains unmentioned in the description.

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%, with wait_s fully explaining the job/polling semantics and design_id explaining its origin. The description adds no parameter-level detail beyond the schema, so the baseline of 3 applies.

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 enumerates the exact copper metrics computed (signal vias per net, share of nets without a via, outer-layer signal copper share, vias in SMD pads, plane stitching) and states the comparison target (reference designer-routed boards with the same layer count) plus the gap_to_designers output. This is far more specific than a restated name. It doesn't explicitly name a sibling to prefer instead, which keeps it below a 5.

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?

There is no when-to-use guidance, no prerequisite, and no routing to alternatives such as score_board, run_drc, or check_physics. The workflow stage (post-routing copper evaluation) is only implicit in the metric list, and nothing says when this tool is not appropriate.

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