pcb_get_trace_lengths

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

With no annotations, the description has to carry the safety profile itself. 'Get' and 'Sums' imply a read-only, non-mutating measurement, which is useful. But it does not state permissions, whether unrouted nets appear, whether vias or pads count toward length, or the scope of 'active PCB' versus other open documents.

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?

Front-loaded with the main statement, then clearly labeled Args and Returns sections. The Returns block partially repeats the output schema, which is slight waste, but the overall structure is efficient.

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?

An output schema exists, so the return value does not strictly need re-explaining. The key missing piece, the undocumented parameter, is covered, making the definition sufficient for correct invocation. Only minor behavioral details are absent.

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 coverage is 0%, so the description must document the parameter, and it does: optional net name filter, behavior when empty (all nets). The only gap is that the string matching is unspecified (exact, wildcard, case sensitivity).

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: total routed track length per net on the active PCB. An agent can tell this is a read/measurement tool. It does not distinguish itself from close siblings such as pcb_calc_length_match or pcb_get_differential_pairs, which also deal with trace length.

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?

It gives intended usage context ('length matching analysis and checking differential pair balance'), which implies when to reach for it. But it never names alternatives or exclusions, so the agent must infer whether to use this versus pcb_calc_length_match or pcb_get_differential_pairs.

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