surface_untrim

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

With no annotations, the description carries the full burden and does so well: it explains that solid faces are refused, that extension_distance with internal causes INVALID_PARAMS with no changes, and it lists the return fields including created/modified/removed bodies. The example further clarifies expected invocation.

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-loads the core action, then presents loop-type behavior, refusal conditions, error cases, return shape, and an example in a compact, scannable order. Every sentence adds useful information without waste.

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?

Given four parameters, no annotations, and no output schema, the description covers the essential behavior, edge cases, error conditions, return structure, and an example. An agent has enough to invoke it correctly and understand the outcome.

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 meaningful semantics beyond the schema by explaining the interaction between loop_type and extension_distance (error case) and by pointing to inspect_query for face refs, though it does not elaborate on units.

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: 'Untrim faces of surface bodies: remove their boundary loops (holes / outer trim).' It clearly distinguishes the operation from trimming and surface modification by naming exactly what is removed, and the parenthetical clarifies the two loop types.

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?

Provides clear context for when to use it (remove boundary loops, with modes for internal/external/all) and when not to use it ('Faces of solid bodies are refused (unstitch them first)'). However, it does not explicitly name competing siblings like surface_trim or surface_trim_cells to route the agent away from them.

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