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

Annotations already mark the tool as read-only, idempotent, and non-destructive. The description adds value by specifying exactly what schema details are returned (fields with types, geometry, count, capabilities). This clarifies expected output without contradicting annotations, and no additional side effects are disclosed, which is acceptable given annotations.

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?

Single sentence that is front-loaded with the action and resource, enumerates outputs without redundancy. No filler words.

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 one-parameter tool with no output schema, the description adequately outlines the return contents. It could mention potential errors or URL format specifics, but the schema covers the example. The annotations cover safety, so the description is sufficient for a simple task.

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 only parameter, url, is fully described in the schema with an example. The description merely repeats 'by url' and does not add new constraints or format details beyond the schema. Since schema coverage is 100%, baseline score of 3 is appropriate.

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?

Description uses specific verb 'Get' and clearly identifies the resource: an ArcGIS Feature/Map Service layer's schema. It enumerates the returned components (fields, geometry type, record count, capabilities), distinguishing it from sibling query_layer which would 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?

Description states the tool retrieves schema information by URL, implying its use when metadata about a layer is needed. It does not explicitly mention alternatives or exclusions, but the specificity of the output makes its use case evident. Since no when-not-to-use is provided, it scores a 4 rather than 5.

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