Assign surface

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

Annotations only cover the safety profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false); the description goes beyond them by disclosing the faces-scoping semantics and the exact SURF_ID6 axis ordering. It still doesn't say whether an existing assignment is overwritten, but it adds meaningful behavioral context.

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?

Two tight sentences, front-loaded with the core action and scoping rule; the only slight clutter is the inline rule-ID citation.

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 4-parameter mutation tool with no output schema, the description covers target types and face scoping adequately; only the overwrite/return behavior is unaddressed.

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 100%, and the description's face-order note ('SURF_ID6 order -X,+X,-Y,+Y,-Z,+Z') largely restates the 'faces' property description. Baseline 3 applies since the schema already carries the parameter detail.

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?

Specific verb+resource with explicit target set: 'Assign a surface (SURF_ID) to an obstacle, vent or geometry.' This separates it from sibling creators like add_surface/update_surface, though no sibling is named to make the distinction 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 explains the scoping behavior (whole object vs. selected faces) but never states when to prefer this tool over alternatives such as update_surface or set_bndf. The bulc-mcp rule citation points to further reading, which is a weak form of guidance rather than an explicit when/when-not.

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