measure_line

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

No annotations provided, so description carries full burden. Discloses coordinate system (image px, origin top-left), render scale factor, and sheet dims in both px and pt. Does not discuss errors, auth, or destruction, but for a measurement tool this is adequate.

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?

Description is compact and information-dense with no redundancy. Front-loads purpose. Could be slightly more structured but efficient.

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?

No output schema, but description explains output (length_lf) and coordinate details. Covers key constraints (min points, scale required, condition behavior). Missing explicit return format or error cases, but adequate for the tool's simplicity.

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 has 0% description coverage; description compensates well. For 'pts' adds min points, open polyline, coordinate system. For 'sheet' implies identifier and scale dependency. For 'condition' explains it commits as linear shape. Adds significant meaning beyond schema.

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?

Description clearly states the tool measures an open polyline to compute length_lf at the sheet's scale. It distinguishes from the sibling 'measure_polygon' by specifying 'open polyline' (polygon would be closed).

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 notes prerequisite ('requires the scale to be set') and optional behavior ('pass condition to commit as linear shape'). Implicitly suggests when to use: for open polylines, not polygons. Does not explicitly mention alternatives or when not to use.

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