rhino_surface_curvature_at

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

Annotations already declare readOnlyHint=true, covering the safety profile. The description adds the 'bridge only' scoping constraint, which is a genuine behavioral trait beyond the annotation, but it is not elaborated (e.g., what happens if a non-bridge surface is passed). No contradiction with annotations.

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?

A single front-loaded sentence with zero filler. The core verb and resource appear first, and the scoping constraint is appended compactly. Every word earns its place.

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 simple read-only query tool with an output schema and readOnlyHint annotation, the description is mostly adequate. However, '(bridge only)' is left unexplained and could mislead an agent about which surface identifiers are valid. The description also never clarifies whether u/v are normalized parameter coordinates, though the schema bounds (0–1) partially cover this.

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% for the core parameters (u, v, surface_id). The tool description at least ties u and v to the evaluation location on the surface, but it adds no detail about what u/v represent (parameter space coordinates), how surface_id is resolved, or the doc_id semantics. It does not compensate for the schema gap.

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?

Description states a specific verb (Evaluate), a precise resource (surface curvature), the kinds of curvature computed (Gaussian / mean / principal), and the location ((u, v)). It clearly differentiates from close siblings like rhino_surface_normal_at and rhino_curvature_analysis without requiring the agent to open any other 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 only usage signal is the cryptic '(bridge only)' qualifier, which hints at a constraint but never explains what 'bridge' means or what surfaces are excluded. No explicit when-to-use versus-alternative guidance is given, despite closely related siblings (rhino_surface_normal_at, rhino_surface_developable_score, rhino_curvature_analysis) existing.

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