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 explicitly listing the return contents (fields, geometry type, record count, capabilities), giving the agent concrete expectations about what it will receive. It does not mention any caveats like potential performance issues, but that is acceptable for a read-only schema operation.

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 primary purpose ('Get an ArcGIS Feature/Map Service layer's schema') and immediately lists the included items. Every word serves a purpose, with no redundancy or filler.

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?

Given the tool is simple (one parameter, no output schema), the description fully covers what it does and what it returns. The parameter is adequately documented in the schema, and the description lists all expected output components, making the tool's behavior clear without an explicit output schema.

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 description already fully covers the 'url' parameter, and the tool description only restates 'by url' without adding new details about format, constraints, or usage. With 100% schema coverage, the baseline is 3, and no additional semantic value is provided here.

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 action verb ('Get') and identifies the exact resource ('ArcGIS Feature/Map Service layer's schema') along with the key details returned (fields, geometry type, record count, capabilities). This clearly distinguishes it from the sibling tool 'query_layer' which is about data retrieval rather than schema inspection.

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 tool's purpose obvious — obtaining schema information by providing a layer URL. It implies the tool should be used when needing layer metadata rather than data, but it does not explicitly contrast it with 'query_layer' or other alternatives. However, the context is clear enough and no misconceptions are introduced.

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