pattern_mirror

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

With no annotations, the description carries the full behavioral burden and does so well. It explains combine behavior and resulting modified_bodies, lists error conditions including INVALID_PARAMS and FUSION_API_ERROR with rollback semantics, and documents the return keys including created/modified/removed bodies and occurrences.

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?

The description is front-loaded with the core operation, then adds combine semantics, refs, errors, returns, and a compact example. Every section contributes useful information without repetition, and the example is short and directly actionable.

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 mutation tool with no annotations and no output schema, the description is complete enough to call correctly. It covers input kinds, plane refs, combine behavior, error handling, rollback, and return payload structure, leaving no major gap for an agent to infer.

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 schema already documents all four parameters, establishing a baseline of 3. The description adds meaningful cross-parameter semantics, especially that combine applies only to body input and joins each mirrored body with its original, and that mixed entity kinds are invalid.

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?

The description gives a specific verb and resource: mirror features, bodies, faces, or occurrences across a plane. It clearly distinguishes the operation from siblings such as pattern_circular, pattern_rectangular, and sketch_mirror by naming the mirrored entity kinds and the plane-based operation.

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 provides clear usage context, including that combine is body-only, that all entities must be of one kind, and that planes can come from origin refs, construction geometry, or inspect_query. It does not explicitly name alternative pattern tools or state when not to use this one, so it falls short of full alternative routing.

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