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

The description discloses the substantive behavior — what counts as a violation, the diff_pair_gap coupling criterion, the X_P/X_N, X+/X-, CAN X_H/X_L name patterns — which is real value beyond the annotations. However it is silent on side effects and statefulness, and annotations declare readOnlyHint=false, so an agent cannot tell whether a 'check' persists results or touches the board; that gap is not addressed.

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?

Two sentences, no filler, and the key differentiator (DRC doesn't check this) is front-loaded. The single long sentence is dense but every clause enumerates a distinct measured quantity that the agent would otherwise have to guess.

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?

There is no output schema, yet the description never says what comes back — a pass/fail list, per-net violation records, or a job handle beyond the wait_s case. It is strong on what is measured but leaves the result shape and any threshold/units to inference, which matters for a tool whose entire value is the report it produces.

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%, so design_id, the pattern constraint, and the wait_s/running-job follow-up with get_board_job are already fully documented in the schema. The description adds nothing about either parameter, so baseline 3 applies; 'the project's net classes' only loosely corroborates that design_id selects a design.

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?

Specific verb plus resource: checks copper against the project's net classes and differential pairs. It explicitly names the boundary against run_drc ('which KiCad's DRC does not') and enumerates the exact quantities measured (narrowest track, length below class width, coupled share at diff_pair_gap, skew), so an agent can distinguish it from run_drc and check_physics 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?

'which KiCad's DRC does not' gives an implicit routing rule to this tool for class/diff-pair conformance, and 'Routing applies the same rules' implies it belongs after routing. But there is no explicit when-to-use, no statement of preconditions (routing finished? rules set via set_design_rules first?), and no mention of the sibling tools that fix these violations (widen_nets, couple_pairs, tidy_copper).

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