items_in_region

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

Annotations already declare readOnlyHint and idempotentHint, so safety is covered. The description adds valuable behavioral context: the kinds of items returned and that a layer filter narrows results. It does not contradict annotations and gives a clear picture of the operation's scope.

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?

The description is two sentences, front-loaded with the core query, and contains no redundant phrasing. Every clause adds meaning: the item list and the optional filter. It is optimally concise for the information conveyed.

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?

Given the presence of an output schema (defining return structure) and annotations (read-only, idempotent), the description is nearly complete. It covers the geometry input and layer filtering, but omits details about the path parameter and coordinate ordering. These gaps are minor for a read-only query tool with schema support.

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%, so the description must compensate. It explains the rectangle corners in mm and the optional layer parameter, but does not clarify the 'path' parameter or the order/meaning of the coordinates (e.g., bottom-left/top-right). This leaves partial ambiguity for the agent.

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?

The description states a clear verb+resource: querying what lies inside a rectangle. It enumerates the item types returned (footprints, tracks, vias, zones, text) and mentions the optional layer filter. This distinguishes it from siblings like measure (distance) and search (text-based) without ambiguity.

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 description implies usage through its purpose but does not explicitly state when to prefer this tool over alternatives or provide exclusions. The optional layer parameter hints at a narrowing use case, but there is no explicit 'use when' guidance, leaving the agent to infer the appropriate context.

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