add_text_on_face

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

Annotations already declare destructiveHint=true, readOnlyHint=false and non-idempotence, so safety is covered structurally. The description adds genuinely useful context: the public unit convention (mm, degrees, kg) and that results come with verified measurements and error evidence. It still does not say what the operation destroys or how the text is applied to the face.

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 the operation stated first, followed by unit convention and verification behaviour. The final sentence about inspecting measurements and error evidence is slightly vague but not wasteful enough to penalise heavily.

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?

This is a 10-parameter destructive mutation with no output schema and no parameter documentation, and the description does not address the most critical ambiguity: what identifies a 'face'. Combined with silence on emboss-vs-engrave semantics and return format, it is under-specified for the tool's complexity.

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 0% across 10 parameters, so the description must carry the load. It does clarify that linear inputs are millimetres, which helps x_mm/y_mm/z_mm/height_mm/depth_mm, but leaves 'face' (a bare string with no format guidance), 'emboss', 'font' and 'name' entirely 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 ('Add text on face'), which an agent can distinguish from siblings like add_boss_on_face or add_hole_on_face that operate on the same 'on face' target. It does not explicitly name those alternatives, so differentiation is inferred rather than stated.

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?

Usage is implied by the name and the unit convention, but there is no explicit when-to-use guidance, no exclusions versus the other *_on_face tools, and no statement of prerequisites (e.g., an active document or a valid face reference).

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