List PCB fills

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

Annotations already cover safety (readOnlyHint, idempotentHint), but the description adds substantive context: no Fill mutation is exposed, netless fills are returned rather than skipped, and polygons are emitted in a 'bounded normalized' form. This is value beyond the annotations, though pagination/rate behavior is unmentioned.

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 sentences, front-loaded with the discriminating scope before the detail about netless fills and the read-only guarantee. Every clause carries information; nothing is filler.

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 shapes need not be restated, and the description still summarizes the notable ones. The one real gap is undocumented pagination parameters, which leaves an agent guessing about result-set bounds.

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 0% and the description never mentions projectId, limit, or offset. The presence of limit/offset pagination parameters is a meaningful behavior an agent must know about, and neither the schema nor the description explains them, so the description does not 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 (List) and resource (native PCB Fill primitives) and explicitly separates it from copper pours/zones, which is exactly the sibling confusion risk with easyeda_pcb_regions. It also enumerates the fields returned, so an agent knows what it gets without opening a 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?

Clear context: use this for native Fill primitives, not pours/zones, and it notes that netless fills are surfaced explicitly with netless=true (a real selection gotcha). It does not name a sibling tool outright or state when-not to call it, so it stops short of a 5.

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