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

Beyond the thin annotations it discloses real behavior: priority ordering (higher fills first), that clearance_mm/min_thickness_mm override rules, thermal=false for solid pad connection, and that remove never touches keepout areas. The only mild tension is remove deleting user zones while destructiveHint=false, but this is not a read/write reversal.

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?

A single dense paragraph, front-loaded with the core action and followed by parameter and workflow semantics separated by semicolons. Every clause carries meaning, though the packing is heavy.

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 mutation tool with no output schema, the description covers ordering, overrides, safety constraints, and the downstream workflow. It is largely sufficient for an agent to invoke correctly, missing only explicit alternative-tool routing.

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?

With only 50% schema coverage the description has to compensate, and it does: it explains priority, clearance_mm, min_thickness_mm, thermal, rect/polygon with the 'default whole board outline' behavior, and the remove name/wildcard syntax. design_id and wait_s remain schema-only but those are self-documented.

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 precise verb+resource ('Add or remove copper zones (pours)') and immediately scopes it: pours a net onto given copper layers over rect or polygon. An agent can distinguish this from add_copper or set_keepouts 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?

Provides clear workflow guidance — 'Run fill_zones afterwards, then run_drc' — and clarifies the remove path (zone or net names, wildcards). It does not explicitly contrast with sibling tools like add_copper or set_keepouts, so it stops short of full when-not guidance.

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