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

Annotations already declare the tool as read-only, idempotent, and non-destructive. The description adds value beyond annotations by specifying the exact output components (fields, geometry type, total record count, capabilities). No behavioral contradictions exist, and the description aligns with annotations while providing additional context about what the tool reveals.

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 a single, well-structured sentence that is front-loaded with the main purpose ('Get an ArcGIS Feature/Map Service layer's schema by url') and then lists the key output attributes. There is zero wasted wording and every element is informative.

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 simple, one-parameter tool with no output schema, the description provides a comprehensive summary of what the tool returns (fields, geometry type, record count, capabilities). It does not detail the exact response format, but that is not necessary given the tool's simplicity and the clear list of outputs. This is slightly above minimal adequacy.

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 fully documents the single 'url' parameter with an example and description, achieving 100% schema coverage. The description merely restates 'by url' without adding new semantic detail. The baseline of 3 is appropriate since the schema already carries the parameter meaning.

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 purpose: retrieving an ArcGIS Feature/Map Service layer's schema by URL, with explicit details on what is returned (fields, geometry type, record count, capabilities). This is a specific verb+resource combination that distinguishes it from sibling tools like query_layer, which likely fetch data rather than schema.

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 establishes a clear context: use this tool to get schema information for a layer, not to query features. While it does not explicitly name alternative tools or exclusions, the phrase 'Get an ArcGIS Feature/Map Service layer's schema' makes the intended use unambiguous and distinct from data-querying tools.

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