pcb_run_drc

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

Annotations already declare readOnlyHint/idempotent/non-destructive, so the safety profile is covered. The description adds real value beyond that: the return shape { passed, errors? } and the build-dependent caveat that some EDA Pro builds report only a boolean (upstream issue #27), so "errors" may be absent. It stops short of describing cost, latency, or truncation behavior.

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 sentences, front-loaded with the action and return shape, then the caveat, then the usage rule. The parenthetical issue reference is slightly verbose but earns its place by explaining the missing-field case.

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 correctly carries the burden of describing the return value and its conditional variability, and the parameter surface is fully covered by the schema. The main remaining gap is that document/instance_id targeting requirements (multi-instance selection) are left entirely to the schema.

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 all eight parameters (document, instance_id, ui, strict, verbose, limit, fields, filter) are already documented in the schema. The description adds no parameter-level detail beyond the informal "with connectivity checks" aside, 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?

States a specific verb and resource ("Run Design Rule Check (DRC) on the PCB"), which is enough to separate it from sch_run_drc and document_validate by domain. It never names a sibling explicitly, so an agent must infer the PCB-vs-schematic split, 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?

Gives a concrete trigger condition: run before any fabrication export, and pairs it with connectivity checks. That is clear usage context, but it offers no exclusions or explicit alternatives (e.g. when pcb_get_design_rules is the better call).

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