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

The readOnlyHint annotation already covers the safety profile, so the description's job is to add context. It does so by defining a domain rule: PENDING status with a past scheduledFor means the client did not respond (overdue). This is real interpretive value not present in structured data, though return format and ordering are unaddressed.

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 sentences, no filler, with the core action front-loaded before the parenthetical filter note. The overdue rule is slightly tangential but earns its place by aiding result interpretation.

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 simple read-only list tool with an annotation-backed safety profile and one explained optional parameter, the description is largely sufficient. Missing ordering/pagination notes are minor against the tool's low complexity.

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?

With 0% schema description coverage, the description must carry the parameter burden. It explains that the single clientId parameter is an optional filter scoped 'by user _id', which gives the id format and the optionality that the bare schema does not.

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 gives a specific verb+resource ('List check-ins') and scope ('for the coach'), plus an optional filter. It is unambiguous and clearly distinct from read/write siblings like create_checkin or get_checkin_answers, but it never names a sibling to explicitly route the agent.

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?

Usage is only implied: the agent infers this lists a coach's check-ins and can narrow to a client. There is no stated when-to-use vs alternatives like get_checkin_answers or create_checkin, and no preconditions mentioned.

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