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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world), and the description still adds material context beyond them: a 50 MB size ceiling, the rule that the user's current location is never used unless typed, that download links are built on open, that no file is saved, and that no copy of the source is retained. These are exactly the retention/privacy/limit facts an agent cannot infer from structured fields.

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 'Use this when...' trigger and organized as trigger, formats, examples, exclusions, limits, privacy. It is a dense single paragraph with some run-on packing, but each clause carries distinct operational information rather than filler.

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?

An output schema exists, so return values need no explanation. For an 8-parameter tool with nested objects, the description still supplies the input triggers, format scope, size limit, location caveat, retention policy, and sibling routing — everything needed to call it correctly.

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 meaning: concrete conversion pairings (GPX track to Shapefile, KML to GeoJSON), which output formats open directly in QGIS, and the disambiguation that 'points' means the places the user asks about rather than the user's own location. It stops short of describing individual parameter mechanics, which the schema already handles.

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 set (open, map, convert) on a specific resource (geographic files) and enumerates the accepted inputs (GeoJSON, KML, KMZ, GPX, zipped Shapefile, CSV, WKT). It also names the sibling it is not (extract_open_data), so the agent can separate it from alternatives without opening schemas.

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?

Gives explicit triggers (user shares/links a file, pastes content, or supplies a point list) and an explicit exclusion ('Not for fetching new data about a place: that is extract_open_data'). It even handles the edge case of oversized inputs that can't be written in chat.

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