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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false. The description adds useful behavioral detail by listing what the tool returns (fields, geometry type, count, capabilities), which goes beyond the generic safety profile. It doesn't contradict 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?

The description is a single, well-structured sentence that front-loads the verb and includes a complete list of return items. Every word carries meaning; there is no fluff or repetition.

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?

The tool has only one parameter, no output schema, and strong annotations. The description fully explains what the tool does and returns (fields, geometry type, count, capabilities), making it adequate for an agent to select and invoke correctly. No additional context is needed.

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 schema covers 100% of parameters (url) with a description and example. The tool description merely references 'by url' without adding new semantic detail, so the baseline of 3 is appropriate. No additional parameter explanation is needed beyond the schema.

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 uses a specific verb ('Get') and names the resource ('ArcGIS Feature/Map Service layer's schema'), then enumerates exactly what is returned: fields (name + type), geometry type, total record count, and capabilities. This clearly distinguishes it from sibling tools like query_layer, which would fetch features 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 makes the usage context clear: call this tool when you need a layer's schema/metadata by URL. It doesn't explicitly mention alternatives or exclusions, but the specificity of 'schema' implies a distinct use case from data-returning tools. A more explicit 'use this instead of query_layer when you need metadata' would earn a 5.

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