Surface Texture Symbol (ISO 21920-1)

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

Annotations supply only destructiveHint=false and a title, so the description carries most of the burden — and it does real work by enumerating the four pre-entity refusal classes and stressing that all validation happens before the first entity reaches the drawing (i.e. no partial symbols). It does not mention layer/side-effect behavior beyond the 'layer' parameter, but the atomicity guarantee is exactly the kind of trait annotations cannot express.

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?

Front-loaded with the drawing action in one sentence, then a compact refusal list rather than prose. The refusal sentence is long and packs four rules into one sentence, but every clause is load-bearing and nothing is padding.

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 14-parameter geometry tool with an output schema and thin annotations, the definition covers the drawing action, the validity contract, and the atomicity guarantee. Placement of optional fields (allowance, leader_to, all_around) is left entirely to the schema descriptions, which is acceptable but leaves the description slightly short of fully self-contained.

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 100%, so the baseline is 3. The description adds constraint semantics the schema does not state outright — that text height is never interpolated across the seven tabulated rows, and that lay/machining/standard are closed sets enforced as refusals — which meaningfully changes how an agent must choose values.

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 ('Draw') and a specific resource ('the 60° surface-texture vee with its annotation'), with the standard named. It is unmistakably distinct from the neighboring symbol tools (weld_symbol, gd_frame, datum_feature, section_line), so an agent can pick it without opening the 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?

The description implies when the tool applies (ISO 21920-1 / ISO 1302 surface texture annotation) but never states when to prefer it over siblings like weld_symbol or gd_frame, nor any prerequisite such as an active drawing or layer state. The refusals list is a validity contract, not usage guidance, so the agent must infer the selection context.

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