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

Annotations already declare readOnlyHint: true, destructiveHint: false, and idempotentHint: true, so the agent knows this is a safe read operation. The description adds valuable behavioral context by stating the return format ('Returns attribute rows (and geometry)') and a sampling approach. No contradictions with annotations. This adds meaningful context beyond 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?

The description is two sentences, front-loaded with the core purpose, and includes a useful example/sampling tip. Every word earns its place; no redundancy or fluff.

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 read-only query tool with 6 parameters (all documented in schema) and no output schema, the description adequately covers purpose, usage, and return format. It mentions the integration with search_datasets, the return of rows and geometry, and a sampling pattern. This is complete for an agent to invoke the tool 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% with each parameter already described (url, limit, where, offset, order_by, out_fields). The description restates these parameters in a grouped, SQL-like manner but adds no new meaning beyond the schema, except for the operational tip. Since schema does the heavy lifting, the baseline 3 is correct.

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's function: 'Query an ArcGIS Feature Service / Map Service layer by its url'. It specifies the resource type (ArcGIS layer), the action (query), and distinguishes itself from siblings by referencing search_datasets as the source of the URL. This is a specific verb+resource+scope definition.

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 gives a clear prerequisite ('by its url (from search_datasets)') and a concrete usage tip ('Use where="1=1" + out_fields="*" to sample'). It implies when to use the tool but does not explicitly mention alternatives or when not to use it. This is clear context with no exclusions, so a 4 is appropriate.

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