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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds meaningful behavioral context: it specifies the HTTP method (GET), public access ('No key'), and the exact readiness fields reported ('billing (test|live|gated) and runner_ready'). This goes beyond what annotations alone provide without contradicting them.

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?

The description is a single, information-dense sentence. It front-loads the most important fact ('Public readiness'), then the endpoint, then the fields, and finally the auth requirement ('No key'). Every word earns its place with no fluff.

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-parameter, read-only health check, the description is complete: it states the HTTP method, public access, and what the response reports. There is no output schema, but the description names the response fields, so an agent knows what to expect. Given the low complexity, nothing essential 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?

The tool has zero parameters, so the baseline is 4. The description mentions no parameters, which is accurate given the empty schema. No additional parameter explanation is needed.

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 clearly identifies the tool as a public readiness/health check: 'Public readiness (GET /health)' and lists the reported fields, 'billing (test|live|gated) and runner_ready'. This distinguishes it from the sibling tools, which are all about inboxes, credits, and keys, by making the health-check scope explicit.

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 makes the usage context clear by labeling the tool as 'Public readiness' and noting 'No key', implying it is for unauthenticated health/readiness checks. It does not explicitly state when not to use it or name alternatives, but the sibling set is so divergent that exclusion guidance is less necessary.

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