Nearest Point on Line

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the agent knows it is safe and idempotent. The description adds that it works offline without API calls, which is helpful but not critical. No contradictions between description and annotations.

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 three short sentences with no unnecessary words. The first sentence states the purpose, the second describes the return value, and the third gives use cases. Information is front-loaded and every sentence adds value.

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 tool's low complexity (3 parameters with full schema coverage, existing output schema, and informative annotations), the description covers all necessary context: purpose, return value, offline capability, and use cases. No gaps are apparent.

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 schema already documents all three parameters. The description adds high-level context (snapping to a line) but does not provide additional detail or examples beyond the schema. A baseline score of 3 is appropriate given the high schema coverage.

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 the tool's action: 'Snap a point to the nearest position on a line or route.' The verb is specific (snap) and the resource is well-defined (line or route), making the purpose immediately understandable. It also distinguishes itself from sibling tools like 'nearest_point_tool' by focusing on lines and routes.

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 provides useful use cases: 'which point on this route is closest to my location?' and map-matching without the API. However, it does not specify when not to use this tool or explicitly mention alternative tools (e.g., map_matching_tool for full matching), leaving some ambiguity for the agent.

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