Verify credentials and upstream reachability

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

Beyond the readOnlyHint and idempotentHint annotations, the description discloses meaningful behavior: it performs exactly one authenticated request, reports the credential source, round-trip time, and distinguishes failure categories, and explicitly says it never returns the credential itself. This adds security-relevant context not present in annotations.

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?

Every sentence earns its place: behavior, output, safety, and usage are covered in a compact, front-loaded description. There is no filler or repetition of the title or annotations.

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 parameterless diagnostic tool without an output schema, the description is complete: it explains what happens, what gets reported, the safety guarantee, and the intended trigger condition. An agent has enough context to invoke it correctly.

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 schema fully covers the input contract. The description adds no parameter details, but none are needed; per the rubric, 0 parameters warrants a baseline of 4.

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 names a specific verb and resource: it resolves the credential, makes one authenticated request to api.resy.com, and reports the diagnostic results. It is distinctly a healthcheck/diagnostic tool, clearly differentiated from the domain-operation siblings like resy_book or resy_cancel.

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 explicitly states when to use it: 'Call this when a real tool fails and you want to know which hop broke.' It does not enumerate alternatives or exclusions, but the usage context is clear and not likely to be confused with the sibling tools.

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