pattern_rectangular

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

With no annotations, the description carries the full burden and does it: it explains that quantities count the original, unit handling, the two distinct failure modes with their side effects (INVALID_PARAMS leaves nothing changed, FUSION_API_ERROR is rolled back), and what the call returns. That is exactly the behavioral context an agent needs before mutating a model.

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 purpose, then labeled blocks (Quantities, Units, Refs, Errors, Returns, Example) that make it scannable despite being dense. A few lines, notably the units/quantity sentence and the closing example, restate information already implied elsewhere.

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 12-parameter mutation tool with no output schema and no annotations, the description supplies the return shape, occurrence-specific extras, rollback behavior and ref provenance. Nothing an agent needs in order to call it correctly is missing.

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%, so baseline is 3; the description earns above that by clarifying the non-obvious counting semantics ('quantity1=3 -> the original + 2 copies') and how plain numbers versus Fusion expressions are interpreted. It doesn't touch symmetric1/2, distance_type or compute, but those are covered by schema descriptions.

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 ('Rectangular pattern: copy features, bodies, faces or occurrences along one or two directions'), which inherently separates it from the sibling pattern_circular, pattern_path and pattern_mirror. The supported entity kinds are enumerated up front, so an agent knows what it can pattern 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?

Gives concrete sourcing rules for every ref type ('bodies/faces from inspect_query, features from earlier feature_* results, directions from inspect_query edges, construction_* axes or origin:X|Y|Z') and the hard constraint that all entities must be of one kind. It never explicitly says when to prefer pattern_circular or pattern_path over this one, so the routing guidance is implied rather than stated.

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