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

Annotations already declare read-only, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuine behavioral detail beyond that: buffer is shape-preserving and measured in metres, area/length are geodesic, and output is GeoJSON with measurements and units — an agent knows what it gets back and in what units.

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?

Two short sentences, operations front-loaded, and the return-value note kept to one line. Minimal waste, though 'shape-preserving' is unexplained jargon and the return sentence partly duplicates the existing output schema.

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?

With an output schema present, omitting return-structure detail is fine. But for a 3-parameter tool with a conditional parameter, it never states that radius_m is required for buffer, nor the units/CRS expectations beyond 'GeoJSON', leaving the main failure mode (buffer without radius) undocumented.

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 67%; the description effectively documents the operation enum by spelling out the valid operations, which the schema leaves unannotated. However it never says radius_m applies only to buffer, that it is bounded to 0–100000 m, or how area/length behave on non-areal geometries, so it does not fully compensate for the gap.

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?

Uses a specific verb (compute) and enumerates the five concrete operations: buffer, geodesic area/length, centroid, convex hull. It does not differentiate from nearby siblings such as isochrone (also reach/buffer-like) or calculate_distance, so an agent still has to reason about which tool to pick.

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 statement of when to use this tool rather than isochrone for a radius-based shape, or calculate_distance for length-like queries. Usage is only implied by the operation list; there are no exclusions or alternative routing.

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