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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered elsewhere. The description adds nothing about what a 'definition' contains, whether query filtering/pagination is supported, or any auth/scope requirements.

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?

Two identical sentences plus an operation-ID boilerplate line; the duplication is waste rather than emphasis, and there is no front-loaded explanation of behavior.

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 nested-object request with a free-form query parameter and no output schema, the description is far too thin: it explains neither the response shape of custom-field definitions nor how the query object constrains results.

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 description coverage is 0% and the two parameters (id and an untyped query object) are undocumented both in the schema and in the description. The path template ':id' hints the id is a lease identifier, but nothing explains the query object's accepted keys or the id's format.

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 is the URL path repeated verbatim, so it does technically name a verb and resource (GET custom-field definitions for a lease). But it is pure restatement of the tool name/title with no elaboration, and it does nothing to distinguish this from the many sibling tools such as get_leases_by_id_custom_fields_values or get_contacts_custom_fields_definitions.

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?

No when-to-use guidance is given. The only hint is that describe_operation provides native request schemas, which is a routing nudge but not a statement of when this tool should be chosen over the sibling definitions/values endpoints.

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