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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds valuable context about what the tool returns (fields, geometry type, record count, capabilities) without contradicting annotations. It does not mention rate limits or auth, but the read-only nature is clear.

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, front-loaded sentence with no filler. Every phrase earns its place: 'schema by url', the list of returned elements, and the scope (Feature/Map Service layer). Efficient and well-structured.

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 adequately explains the return values (fields, geometry type, record count, capabilities). It does not elaborate on what 'capabilities' includes, but the core information is present and sufficient for most use cases.

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 a single 'url' parameter fully described in the input schema. The description adds the phrase 'by url' which reiterates the parameter's role, but does not provide additional format or behavior details beyond what the schema already offers. Baseline 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?

The description uses a specific verb ('Get') and clearly identifies the resource ('an ArcGIS Feature/Map Service layer's schema by url'). It explicitly lists what the tool returns (fields, geometry type, total record count, capabilities), making it easy to distinguish from sibling tools like query_layer.

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 clear context on when to use this tool: when you need schema-level information for an ArcGIS layer. It does not explicitly name alternatives or exclusions, but the purpose is specific enough to imply usage. No misleading guidance.

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