dim_linear

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explains that by default it measures exact coordinates, and that snap=True changes behavior to snap onto nearby geometry, including the critical caveat of silently measuring the wrong distance. This is valuable beyond what the schema shows, but it does not discuss other potential behaviors like return values or side effects.

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 primary purpose, and every clause adds value: the core functionality, the key parameter (line_x/line_y), the exact-coordinate behavior, and the snap warning. No filler or repetition.

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 tool's complexity (7 params, no schema descriptions, no annotations) and the presence of an output schema, the description provides enough context for correct invocation: what it does, how to position the dimension line, and the snap trade-off. It doesn't cover prerequisites like an open drawing, but that is likely shared with all sibling tools and not necessary for this tool's selection.

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 add meaning to parameters. It explicitly explains line_x and line_y as 'dimension line position' and snap as a boolean controlling object snap, while 'between two points' and the coordinate names (x1, y1, x2, y2) implicitly define the remaining parameters. This compensates well for the lack of schema descriptions, though it doesn't exhaustively detail each coordinate parameter.

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 'Linear (horiz/vert) dimension between two points' which identifies the tool as a horizontal/vertical dimension tool, distinguishing it from siblings like dim_aligned, dim_radius, etc. The verb 'dimension' and resource 'two points' are specific and unambiguous.

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?

Provides clear context for when to use snap mode ('handy to dimension existing entities') and warns about the risk ('can silently measure the wrong distance'). However, it does not explicitly compare with alternatives such as dim_aligned, leaving the differentiation to the 'horiz/vert' description rather than an explicit 'use this instead of X' statement.

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