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

Annotations already establish readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds real value by disclosing the diagnostic model: corridor checks per layer, via-site feasibility, named blockers, CRAMPED detection with 'no router can reach it', and rip-and-retry advice. It does not mention that long runs return a 'running' job status, though the wait_s schema param covers that.

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 dense but purposeful sentences; the scope condition is front-loaded and the sibling routing rule comes last. Slightly run-on phrasing around the parenthetical blocker list costs it a point, but every clause carries information.

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, so the description must carry the return contract itself, and it does: per-pad corridors, via-site verdicts, responsible blockers, CRAMPED classification, and actionable advice. The only gap is the async job lifecycle, which is handled by the wait_s parameter documentation rather than 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 coverage is 80%, so most parameters are already documented, giving a baseline of 3. The description repeats rather than extends what the schema says about nets and reach, adding no format or interaction detail (for example how max_nets interacts with nets, or how reach_mm changes CRAMPED verdicts).

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: per open net, report each pad's free escape corridors, whether a via can be dropped, and what blocks it. It also names concrete verdicts (CRAMPED) and the advice it returns, so the agent knows exactly what it gets back 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?

Names the sibling alternative explicitly (repair_board) and the condition that selects this tool: a net that keeps failing. That is a clear when-to-use rule tied to a real tool in the sibling list, leaving nothing to inference.

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