add_centerline

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

With no annotations, the description carries the full burden. It discloses that centerlines are non-geometric entities used for reference only, which is helpful. However, it does not describe behavioral traits like whether it modifies the existing sketch, if it requires an open sketch, or what happens on failure. The output schema exists but its content is not summarized.

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 concise with two sentences, front-loading the action. It avoids unnecessary words, but could include a brief note about prerequisites or returned values without becoming verbose. Still, it earns a 4 for being efficient and clear.

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 the complexity of the input schema (multiple coordinate parameters) and the presence of an output schema, the description provides the core purpose and nature of the tool. However, it lacks context about the surrounding sketch environment, such as needing an active sketch or how the centerline interacts with other sketch geometry. This gap prevents a higher score.

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 the baseline is 3. The description does not add meaning beyond the schema; it does not explain how parameters like coordinates or the construction flag affect the centerline. The schema already describes each field adequately.

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 clearly states 'Add a centerline to the current sketch' with a specific verb and resource. It also explains that centerlines are construction/reference lines for symmetrical features or revolution axes, distinguishing it from regular lines (add_line) and other sketch entities.

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?

The description mentions usage as a centerline for symmetrical features and revolution axes, providing some context. However, it does not explicitly say when to use this tool versus alternatives like add_line or add_sketch_constraint, nor does it mention prerequisites (e.g., an active sketch).

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