create_pattern

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

With no annotations, the description carries the full burden of behavioral disclosure. It goes beyond the verb by stating that it returns the pattern_index and outline lines for immediate sewing, hemming, or topstitching. It does not describe side effects like project mutation or failure behavior, but the key call behavior is adequately exposed.

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 tightly organized: one purpose sentence, a clean args block, and a useful return note. Every sentence contributes either to parameter semantics or to why the return value matters, with no redundant filler.

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?

Even without an output schema, the description tells the agent what input to provide and exactly what will be returned, including line_index, start, end, and length. For a single-parameter creation tool, the information needed to invoke it correctly is present and actionable.

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 0%, but the description fully compensates: it explains points as [x, y] or [x, y, type], defines each type code (0=straight, 2=spline, 3=bezier), specifies mm units, and provides a concrete example. This is exactly the semantic detail an agent needs beyond the bare array schema.

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 opens with 'Create a new pattern piece from vertex points', giving a specific verb and resource. It clearly distinguishes this from siblings like copy_pattern, delete_pattern, and get_pattern_info because it is the constructive action that builds geometry from coordinates.

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?

Usage context is implied rather than stated: an agent can infer this is for creating a pattern from raw vertex coordinates. However, the description does not explicitly say when to prefer this over alternatives such as import_file or copy_pattern, and it provides no exclusion criteria.

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