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

Adds genuine value beyond annotations: discloses the exact return payload shape and the important trait that it makes no upstream Oura call (no latency/quota cost). Annotations already cover readOnly/idempotent/no-open-world, so this is solid extra context without full failure-mode detail.

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, front-loaded with the return value, then purpose, then the negative scope. Zero 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 zero-param health-check tool with annotations covering safety, the description covers return shape, purpose, and isolation from the backend. Nothing needed to call 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 baseline is 4; the description correctly requires no argument input and instead describes the output shape.

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?

Specific: states it returns {ok: true, user_id} and its purpose is verifying auth + connectivity. Explicitly states 'Does not call Oura,' which cleanly distinguishes it from all 19 data-fetching siblings.

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?

Implied usage is clear — call this to verify credentials/connectivity before other calls. It explicitly rules out the data-fetching use case of siblings, but doesn't say e.g. 'use as a first-call handshake' or when-not-to-call.

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