health_check

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

With no annotations, the description carries the full burden and does well: it declares the operation read-only and cheap, and discloses what each service reports (ok status, duration, and for an expired Reminders session the exact fix command). It stops short of covering auth prompts or network/permission prerequisites.

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 short sentences, all load-bearing: what it checks, what it returns, and when to call it. The failure-triage cue is placed last as a callback, which is effective rather than wasteful.

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 no-param diagnostic with no output schema, the description covers purpose, cost, return shape, and remediation guidance adequately. It could be slightly more explicit about what a failing check looks like, but nothing essential for calling it correctly is missing.

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?

Zero parameters, so per the rubric the baseline is 4. The description correctly implies no input is needed, and there is nothing further for it to document.

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 precise verb+resource: checks reachability and sign-in state for Calendar (CalDAV) and Reminders/Notes (CloudKit). This is clearly distinguishable from every sibling, which are all functional CRUD/query tools on calendars, events, reminders, and notes.

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?

Gives an explicit trigger: 'Call this first when another tool fails oddly.' That is a clear when-to-use condition tied to the failure of the sibling tools. It does not name a when-not-to-use case, but for a cheap diagnostic probe that exclusion is largely implicit.

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