List PCB fills

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

Annotations already declare readOnlyHint and idempotentHint, so repetition of 'read-only' earns nothing, but the description adds real behavioral detail the annotations cannot: netless fills are returned explicitly with netless=true, and the polygon is a bounded normalized representation. It doesn't mention pagination behavior or ordering, which keeps it off a 5.

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?

Three compact, front-loaded sentences with no filler; the distinguishing clause comes first and the field inventory follows. Slightly list-heavy but every element is substantive.

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 return-shape explanation is not required, but for a 3-parameter paginated listing tool the description never covers limit/offset semantics and gives no routing to easyeda_pcb_regions for pours. Adequate, with a clear pagination gap.

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 only 33% — only projectId carries a description, while limit and offset (with defaults and a 1-200 maximum) are undocumented in both schema and description. The description says nothing about paging or how limit/offset interact, so it fails to compensate for the coverage gap.

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 ('List native PCB Fill primitives') and explicitly scopes it apart from copper pours/zones, which is exactly the distinction that separates it from the sibling easyeda_pcb_regions. The listed payload fields reinforce what the tool actually returns.

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?

The sentence 'Read-only; no Fill mutation is exposed' implies this is the inspection path and warns that no write counterpart exists, but there is no explicit instruction on when to pick this over easyeda_pcb_regions or the other pcb listing tools. Usage is inferable rather than stated.

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