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

Annotations already convey read-only, idempotent, non-destructive behavior. The description adds useful context about bulk execution and $expand, which are not in annotations. It does not contradict annotations and provides extra operational detail, justifying a score above baseline.

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 two concise sentences, front-loaded with the core purpose, and includes only essential extra info (bulk support). No filler or redundancy.

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 has no output schema and multiple optional parameters, the description does not sufficiently explain the query and $select parameters, nor the response format (single vs. multiple objects). While annotations cover safety, the description lacks enrichment for complete invocation, especially for bulk use.

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 0%, so the description must explain parameters. It clarifies id (implicitly), ids for bulk, and $expand, but leaves query and $select unexplained. This is only partial coverage of the 5 parameters, and the description does not fully compensate for the missing schema descriptions.

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 clearly states the tool retrieves custom field definitions by ID, matching the OData endpoint pattern. It distinguishes from the sibling list tool by indicating it fetches by specific id, and mentions bulk support for multiple ids.

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 gives usage hints like using $expand for sub-resources and bulk execution for multiple ids, but does not explicitly contrast with alternative tools (e.g., list_customfielddefinitions). It implies usage when a specific id is known but lacks explicit 'when not to use' guidance.

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