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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered. The description adds value beyond that by disclosing what is returned, that the call is inexpensive, and that the token's region is implicitly validated — context an agent cannot get from the annotations alone.

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?

Three compact clauses with the core purpose front-loaded, then the cost/verification rationale, then the endpoint reference. No sentence is padding and nothing important is buried.

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?

No output schema exists, so the description correctly enumerates the return payload and ties one field to a downstream write tool. The remaining gap is that it does not mention the optional 'fields' override, but the schema carries that detail fully.

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 100% and the single 'fields' parameter is documented thoroughly in the schema with a nested-resource example. The description never mentions field selection at all, so it adds nothing on top of the schema; baseline 3 applies.

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 a specific verb and resource — 'Fetch the Clio user this access token belongs to' — and enumerates the returned fields (name, email, subscription type, time zone, default_calendar_id). This clearly separates it from the sibling clio_list_users, which lists many users rather than identifying the token owner.

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?

'A cheap way to confirm the token and region are right' gives an explicit usage context, and the note that default_calendar_id is 'needed to create calendar entries' points the agent forward to clio_create_calendar_entry. It stops short of naming an alternative or stating when not to use it, so it falls just below a 5.

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