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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely useful behavior beyond that: distance is computed from parquet bounding-box centres rather than true geometry, so ranking is approximate, and the response contains the true in-radius count plus the nearest `limit` features. It does not mention performance characteristics or empty-result behavior.

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?

Three front-loaded sentences: purpose and ordering first, then the distance-computation caveat, then the return shape, then a compact example. No filler and nothing repeated from the schema or annotations.

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 no output schema, the description usefully explains the return payload (true count plus nearest `limit`). All five parameters are documented in the schema and safety is covered by annotations. What remains unstated is the shape of each returned feature and behavior when nothing is in radius, which is minor for a read-only spatial query.

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 meaning the schema does not: results are ordered nearest-first, `limit` truncates to the nearest N rather than an arbitrary N, and a concrete parameter example is supplied. The schema-only facts (defaults 20/25, max 200) are left to the schema, which is fine.

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 gives a specific verb and resource ('Find features from a layer that are near a given point') plus ordering and radius scoping, so the operation is unambiguous. It never names a sibling such as query_layer or locate to differentiate spatial-radius lookup from attribute filtering or address geocoding, so it stops short of the top score.

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?

Usage is conveyed only by the worked example ('reservoirs near Bengaluru' -> layer_id/lat/lng/radius_km), which implies the when-to-use scenario without stating it. There is no explicit guidance on when to prefer this over query_layer or locate, and no stated preconditions or failure cases.

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