Tokens in range

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

Annotations already establish that this is a safe, read-only, idempotent operation. The description adds genuinely useful behavioral details beyond those annotations: results are ordered nearest first, optional wall/sight filtering, and no canvas requirement is needed. This is meaningful context for an agent deciding how to invoke the tool.

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 compact, with two sentences that carry distinct value: the core behavior and the optional sight-filtering mode, plus the important canvasless guarantee. There is no filler or redundant restatement of the tool's title.

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?

For a read-only list operation with complete parameter documentation and safety annotations, the description is nearly sufficient. It captures ordering, sight filtering, and canvas independence, while the schema handles parameter semantics. The lack of an output schema means some return-format detail is not disclosed, but it is not critical for correct invocation.

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 input schema covers 100% of parameters with descriptions, so the baseline is 3. The description adds little beyond what the schema already documents, although terms like 'scene units' and 'token or point' reinforce the schema's meaning. It does not compensate for any parameter gap because none exists.

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 clearly states a specific verb and resource: it lists tokens within a distance with nearest-first ordering. It also conveys the optional line-of-sight filtering, making the tool's behavior easily identifiable. It does not explicitly differentiate itself from sibling tools by name, though its scope is distinct enough.

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 gives useful context about when the tool applies, notably that it works without a drawn canvas and can filter by line of sight. However, it does not explicitly state when to use this tool over alternatives such as measure-distance or check-wall-collision, leaving that routing implicit.

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