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

Goes well beyond the readOnly/idempotent/openWorld annotations: it discloses CRS handling per operation (WGS 84 for overlays, local equidistant for buffer/simplify/centroid), hard limits (20,000 features, 100,000 vertices, 10,000 for buffer), that download links are built lazily on open with no file saved, and that TerraLab keeps no copy. The 'no file is saved' and 'never pass these links to open_gis_file' notes are exactly the kind of behavior annotations cannot express.

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?

Front-loaded with the trigger clause and every sentence carries information — operation list, CRS, limits, return payload, exclusions, link semantics. It is a single very dense run-on paragraph, though; the exclusion and call-shape rules would scan faster as separate sentences.

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 13-parameter tool with nested objects and an output schema, the description covers what an agent needs before calling: which inputs are accepted, which parameters go with which operation, coordinate system expectations, size ceilings, and what the downloads are. Return-value detail is duplicated only briefly and the output schema carries the rest.

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, but the description adds real cross-parameter semantics the schema cannot: radius_m is scoped to buffer, tolerance_m to simplify, dissolve_field to union (one feature per value vs. one feature), and area applies only to clip with place/radius/bbox forms. It does not restate the numeric bounds or formats enum, which it correctly leaves to the schema.

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 names the concrete verb (apply one GIS operation) and enumerates every operation the tool supports — buffer, union/dissolve, intersection, difference, clip, simplify, centroid, area_length — plus the input forms and the file output. It explicitly distinguishes itself from the two nearest siblings, measure and open_gis_file, so an agent can route without opening the schema.

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?

Starts with an explicit 'Use this when...' trigger, then gives two explicit negative exclusions with the correct alternative named for each ('that is measure', 'that is open_gis_file'). It also adds a usage rule ('Never use the user's current location unless they type it') and a call-shape rule ('list every format the user needs in formats, in this one call').

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