select_edge_at_point

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

Adds real behavioral context beyond annotations: the coordinate system is model mm, and append=True accumulates into the current selection (implying default replaces it), which the schema does not encode. The hint that it can be used to 'check that a point really lies on an edge' also implies it may fail to find a match, though the failure behavior itself is never stated.

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 tight sentences, front-loaded with the action and coordinate convention, then the parameter behavior, then the usage caveat. No filler or restatement of the tool name.

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?

An output schema exists, so return values need not be explained; the description covers units, selection-state side effect, and the practical caveat. The only gap is what happens when no edge passes through the point (error vs. empty selection), which matters for a tool sold as a validation check.

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% (bare titles like 'X Mm'), so the description must carry the burden — and it does, establishing that the three coordinates are a single point in mm model coordinates and defining append's effect. It omits what happens when append is omitted (default false) and any tolerance for the point match.

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?

Opens with a specific verb and resource ('Selects the edge of the part') plus the selection criterion ('passing through the point (x, y, z)'). This is enough to distinguish it from sibling select_face_at_point and from sketch/feature tools without opening a schema.

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 use case and discourages misuse: fillet/chamfer take points directly, so this is mainly for verifying a point lies on an edge. It stops short of naming select_face_at_point as the alternative for face selection, so it isn't fully exhaustive.

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