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 the typed-id format (property:<uuid>, contact:<uuid>, deal:<uuid>) and the contact-specific email/phone exception, including the fact that search never returns those fields. This goes beyond the annotation baseline, though it doesn't describe full return shapes.

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 focused sentences, front-loaded with the core operation and input format. The qualification about contact email/phone earns its place because it explains behavior that would otherwise be surprising. No 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?

For a one-parameter, read-only fetch with strong annotations, the description is nearly complete: input format, allowed types, and the notable contact-field exception. The only minor gap is that the return shape for property and deal fetches is not explicitly described, and there is no output schema to fill that in.

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 only defines id as a string with no description (0% coverage). The description fully compensates by specifying the expected typed-id format and accepted entity types, so an agent knows exactly what to pass.

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?

States the operation ('Fetch') and resource scope ('one property, contact or deal'), and specifies the input source ('typed id search returned'). The mention of the get_contact exception and 'search itself never returns either' helps distinguish this tool from search and the typed getters.

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 clearly frames when to use this tool: after search, with a typed id from the results. It does not explicitly enumerate when-not conditions or alternatives beyond the get_contact exception, but the context is unambiguous enough for selection.

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