List PCB constraint regions

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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered; the description adds useful behavioral context beyond them by disclosing that polygons are returned in a bounded, normalized form and that no region mutation path exists at all. It does not discuss pagination or result-size behavior, which matters given the limit/offset pair.

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 tight sentences with the identity/scope statement front-loaded and the read-only caveat last. Dense but every clause carries information; no 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-shape explanation is unnecessary, and annotations carry the safety profile, leaving the description appropriately lean. The one real omission is any mention of pagination behavior for limit/offset, which an agent calling with a large region set would need.

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 only 33% (only projectId is documented), and the description says nothing about parameters at all. limit and offset have defaults and bounds in the schema, but the description never explains pagination semantics, so it 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 and resource (List native PCB Region primitives) plus the returned fields, and explicitly carves out the boundary versus copper pours/zones, which is exactly the distinction an agent needs against the sibling easyeda_pcb_fills.

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 phrase 'separately from copper pours/zones' gives clear selection context and implicitly routes pour/zone queries elsewhere, and 'Read-only; no Region mutation is exposed' tells the agent this is the only region entry point. It stops short of naming a specific alternative tool or stating exclusions explicitly.

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