extend

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

No annotations are present, so the description carries the full burden of behavioral disclosure. It mentions the straight-line restriction and the general result, but it does not state whether the target is mutated in place, what happens when no intersection exists, or whether the operation is destructive or reversible. For a geometry modification tool this is a meaningful gap.

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 one sentence with no filler, and the core verb and object are front-loaded. The parenthetical is compact but slightly awkward, mixing a parameter name with an enum value and reducing immediate clarity.

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 three-parameter geometry mutation with no annotations, this description leaves important gaps: parameter semantics, mutation behavior, edge cases, and usage context. An output schema may document return values, but that does not help an agent know how to construct a valid `target` and `boundary` or what to expect when the extension is impossible.

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 for the missing parameter docs. It partially does by implying `target` is a straight line and `boundary` is the thing to meet, and it connects `end` to the enum values. However, it never explicitly defines `target`, does not explain what "nearest" means relative to the line's endpoints, and provides no detail on how the entities are referenced.

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 an operation (extend), a resource (a straight line), and a termination condition (until it meets `boundary`). However, the parenthetical "end = "start", "end" or "nearest"" is ambiguous because "end" is both the parameter name and one of the enum values, and it does not explicitly distinguish target from boundary. Still, an agent can tell this apart from trimming or offsetting.

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?

There is no guidance about when to use `extend` rather than sibling tools like `trim`, `offset`, or the line-creation tools. No prerequisites or selection context are provided, so the agent must infer the intended use case entirely from the one-line description.

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