layer_info

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds the meaningful behavioral detail that the call performs a full scan (invalid geometry detection, per-field null counts) and reports a degrees/CRS check, which primes the agent for what the call inspects. It omits cost hints for very large layers and what happens when a multi-layer file is passed without the layer argument.

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-loads the purpose and the "call this first" directive, then a clearly separated Args block. The enumeration of return contents is dense but earns its place by signalling scan depth; only the return-value listing mildly overlaps 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?

For a two-parameter read-only inspection tool with an output schema, the description covers purpose, sequencing, both parameters, and the scope of what is examined. The remaining ambiguity (layer resolution on multi-layer files, runtime on large inputs) is minor and does not affect correct invocation.

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 description coverage is 0%, so the description carries the full burden and does so: it names supported vector formats for path (GeoPackage, Shapefile, GeoJSON, KML, FlatGeobuf) and explains that layer is the optional layer name inside a multi-layer file such as a GeoPackage. Both parameters gain meaning that the bare schema lacks.

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 and resource (describe a vector layer) and immediately enumerates the concrete outputs: CRS with a degrees flag, feature count, missing/empty/invalid geometries, geometry types, bounds, and per-field null counts. The siblings are all analysis tools, and the description makes clear this is the metadata/inspection counterpart an agent should run before them.

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?

"Call this first on every layer" and "before any analysis" give an explicit precondition for invocation, which is exactly what an agent needs for sequencing. It stops short of naming any sibling tools or stating when-not to use it, so it falls just short of the top band.

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