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

Despite annotations, the description adds substantial behavioral detail: no movement or added vias, score unchanged, pours refilled after each net, disconnected widenings backed out, and remaining necks reported. This goes well beyond the readOnly/destructive/openWorld annotations.

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?

The description is front-loaded with the action and tightly organized: purpose, constraint, rationale, ordering advice, guard behavior, and result reporting. Every sentence contributes useful operational context.

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?

For a six-parameter mutation tool with no output schema, the description covers the important behavior: in-place widening, optional vias, guard/backout semantics, pour refill, ordering, and what the result reports. Nothing critical is left implicit.

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 parameter semantics are already well supplied by the schema, including nets, vias, guard, necks, wait_s, and design_id. The description adds usage ordering for nets but little parameter-level syntax beyond what the schema provides.

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 gives a specific verb and resource: "Grow the tracks (and optionally vias) of the named nets in place." It also distinguishes the operation from routing-like siblings by stating "Nothing moves and no via is added" and explains the intended power-net necking context.

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 clear operating context (routers neck power down; most necks have room) and an explicit ordering rule: "List the heaviest current first: earlier nets take the room." It does not explicitly name sibling alternatives or when not to use it, which keeps it below a 5.

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