drawing_extents

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

readOnlyHint=true already covers the no-mutation profile, but the description adds value annotations can't: 'Side-effects: None', 'Read-only bounding box query', and specifically that the view is not changed. It could go further on coordinate system edge cases (e.g., empty drawing or extents of frozen layers), which is why it isn't 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 short labeled lines – purpose, side-effects, disambiguation – with the core action front-loaded and zero filler. Every sentence carries distinct information.

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?

A parameterless read-only query with an output schema, so return-value documentation isn't required; the description nonetheless hints at the shape ([min_x, min_y, max_x, max_y]) and WCS frame, and covers side effects and view invariance. Nothing needed to invoke it correctly is missing.

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?

The tool takes zero parameters, so the baseline is 4; the schema is fully closed (additionalProperties: false) and there is nothing for the description to disambiguate. It correctly adds no noise about arguments.

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 (measure) and a precise resource (current drawing-space WCS extents), plus the mechanism (backend geometry engine). The disambiguation line distinguishes it from view-changing siblings such as view_zoom_extents, so an agent can select it without opening schemas.

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?

Explicitly says it 'does not change view', which implicitly routes view-modifying needs to view_zoom_extents, and notes it does not alter document objects. It stops short of naming an alternative tool outright, so not a full 5.

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