extend

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

No annotations are provided, so the description carries the full burden. It states the mutation (extend by 20 percent) but says nothing about which end extends, whether it is reversible/undoable, what boundary_entities constrain, or error behavior on non-line entities.

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?

A single short sentence with nothing wasted and the action front-loaded, but it is under-specified relative to the tool's complexity rather than genuinely well-proportioned.

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?

A geometry mutation tool with no annotations, no output schema, and undocumented parameters needs more than a magnitude statement. The agent lacks what it needs to call this correctly on edge cases.

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 0%, so the description must compensate, but it explains neither entity_id (only implied as 'line-like entity') nor the optional boundary_entities, which is completely unaddressed despite likely controlling extension limits.

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 (extend) and a specific resource class (line-like entity) with a concrete magnitude of 20 percent. It is clearly distinct from offset/trim in intent, though it doesn't name siblings explicitly.

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?

No guidance on when to use this versus offset, trim, or fillet_2d, and no preconditions. The agent must infer that this only applies to open line-like geometry.

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