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

Goes well beyond the annotations: discloses that nothing moves, no via is added, the score does not change, pours are refilled after each net, disconnecting widenings are backed out (the guard), and the result reports what still holds each neck. This is exactly the mutation-behavior detail an agent needs and is consistent with readOnlyHint=false / destructiveHint=false.

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 core action in sentence one, then rationale and constraints. Nearly every sentence carries information, though the 'Routers neck power down...' sentence is partly persuasion and adds length to an otherwise dense block.

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 multi-parameter mutating tool with no output schema, the description covers the important gaps: what changes, what is preserved, the ordering effect, the safety back-out, and what the result names. It even points to get_board_job for the running case via the wait_s 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 coverage is already 100%, so the baseline is 3. The description adds real meaning on top: 'up to the net's target width' maps to the nets map, 'a via only ever grows' clarifies the vias map, and the backing-out rule explains the guard flag. wait_s and necks are left to their schema text.

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?

Opens with a precise verb+resource+scope: 'Grow the tracks (and optionally vias) of the named nets in place... up to the net's target width.' The constraints (nothing moves, no via added) cleanly separate it from cousins like route_board, ripup_routing, and fill_zones without naming them.

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?

Strong contextual guidance for when this applies ('Routers neck power down to the signal width... most necks have room around them') plus an ordering rule ('List the heaviest current first: earlier nets take the room'). It stops short of naming an alternative tool or stating when not to use it, so it is clear but not fully routing-aware.

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