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

The annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering safety. The description adds valuable context about what 'schema' means here, listing fields, geometry type, record count, and capabilities, which goes beyond the minimal annotation information.

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 sentence, front-loaded with the verb 'Get', and contains zero filler. Every word contributes to clarity and the output contents are compactly listed.

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 tool with one parameter and no output schema, the description fully specifies the expected return values (fields, geometry type, record count, capabilities). There are no missing behavioral or safety details that could prevent correct invocation.

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 provides 100% coverage of the single 'url' parameter, including type, description, and an example. The description only repeats that the operation is 'by url', adding no new semantic detail beyond what is already in the schema. Baseline 3 is appropriate because the schema handles the parameter documentation.

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 the specific verb 'Get' and clearly identifies the resource: 'an ArcGIS Feature/Map Service layer's schema by url'. It also enumerates the exact output contents (fields, geometry type, record count, capabilities), which distinguishes it from sibling tools like query_layer that retrieve actual data.

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 does not explicitly state when to use this tool versus alternatives, nor does it mention exclusions or prerequisites. The use case is implied by the purpose 'Get ... schema', but there is no direct guidance such as 'use query_layer for data queries'.

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