assembly_faces

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

With no annotations, the description carries the full burden and does disclose the two traits that matter most operationally: the search spans sub-assemblies and results are returned in TOP assembly coordinates in millimetres. It also pins the returned ref format, which is what makes the tool chainable. It does not state that the operation is read-only or address multi-instance selection, which stays implicit.

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?

Purpose is front-loaded in the first sentence, followed by a compact args block where each line carries concrete, non-redundant information (examples and units rather than restating schema titles). Slightly dense but no filler sentences.

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-style query tool with a 8-param schema, no annotations, and an output schema already present, the description supplies the missing essentials: coordinate frame, units, ref format, and the origin of the path argument. Remaining gaps are minor (instance selection, ordering/limit interplay) and partly covered by structured fields.

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 description coverage is only 13%, so the description must compensate, and it largely does: it gives concrete examples for path ('Z AXIS:1/FIXED PLATE:1'), normal ([0, 0, 1] for faces looking up), at ({"Z": 182.5}), plus units for diameter and semantics for min_area and max_count, and enumerates surface values. Only the instance parameter is left undocumented in the text (though the schema covers it).

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 ('Find faces of a component') and narrows scope precisely: whole assembly including sub-assemblies, results in TOP assembly coordinates in mm. That scoping clause implicitly separates it from the component-scoped siblings like list_faces and find_face, but it never names them, so the differentiation is inferential rather than explicit.

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?

It says where the required path comes from ('Component path from list_occurrences(depth=2)') and what to do with results ('Each result has a ref ... that constrain_faces takes'), which is real routing guidance to two sibling tools. It also clarifies sub-assembly recursion. No explicit when-not-to-use or alternative-selection rule is given, keeping it below a 5.

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