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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false, covering safety. The description adds useful behavioral context: it returns attribute rows and geometry, and suggests a sampling pattern. It does not mention auth or rate limits, but given the annotation coverage, this is acceptable.

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?

The description is three sentences long, each sentence earns its place: first states the core purpose, second lists the key parameters, third provides a usage example. No redundant wording or 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?

Given the well-annotated schema (100% coverage, read-only hints), the description is quite complete: it covers the source of the URL, the query capabilities, and the return type. It does not explicitly explain pagination flow (e.g., using offset for next pages), but the schema already documents offset and limit, so this is a minor gap. No output schema exists, but the return type is stated as attribute rows and geometry.

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?

The input schema has 100% coverage for all six parameters, so the baseline is 3. The description adds value by summarizing the parameter family (SQL-like where, comma-separated out_fields, order_by, limit, offset) and by pointing out that the URL comes from search_datasets, which enriches the url parameter's meaning. The sampling tip also connects parameters in a practical way.

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 clearly states the tool 'Query an ArcGIS Feature Service / Map Service layer by its url', which is a specific verb+resource. It also distinguishes from siblings by mentioning 'from search_datasets', implying search_datasets is for finding datasets and query_layer is for querying 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?

The description provides a clear usage context: first get a URL from search_datasets, then query this layer. It also gives a practical tip for sampling (where="1=1" + out_fields="*"). However, it does not explicitly state when NOT to use it compared to alternatives like layer_info or search_within, so it stops short of full exclusion guidance.

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