nx_measure_distance

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

With no annotations, the description carries the safety burden and does it well: it declares this is a read-only query that creates no annotation, and discloses the return contents (numeric mm distance plus two closest points). It stops short of stating error or precondition behavior for invalid edge indices.

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 sentences with zero filler, and the core purpose is front-loaded ahead of the query/return details.

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 three-parameter read tool with an output schema, this covers purpose, read-only nature, return shape, and index provenance. Only preconditions on the target body are left implicit.

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 coverage is 0%, so the description must compensate. It adds the critical fact that edge indices are 0-based and come from nx_list_edges, which the schema does not say, but body_id and argument ordering remain unexplained.

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: 'Measure the minimum 3D distance between two edges of a body.' No sibling tool measures distance, so an agent can identify this uniquely from the description alone.

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 frames the tool as a QUERY and explains the payoff: 'so an agent can verify geometry instead of guessing.' There is no competing measurement sibling to exclude, but it does not state prerequisites such as needing an open part or body loaded.

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