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 adds valuable behavioral details: it makes exactly one authenticated request, reports the credential source and round-trip time, and never returns the credential itself. It also explains the three outcome categories it distinguishes, which is genuinely useful.

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 sentences, all informative and none redundant. The core purpose is stated first, followed by output reporting details and a clear call-to-use trigger. The structure is easy to parse.

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?

Given no parameters and no output schema, the description covers what an agent needs: what the tool does, what signals it returns, when to call it, and a critical safety detail (no credential leakage). This is complete for the tool's 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?

The tool has zero parameters, so the description cannot add parameter-level meaning. The baseline of 4 applies because no parameter documentation burden exists; the description appropriately focuses on behavior instead.

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 states a specific diagnostic action: resolve the credential, make one authenticated request, and report which hop failed. It distinguishes itself from the sibling data-retrieval tools by framing this as a healthcheck rather than a data operation.

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?

It explicitly says 'Call this when a real tool fails and you want to know which hop broke,' giving clear usage context. It does not explicitly name when-not-to-use cases or alternative tools, but such exclusions are not necessary given the tool's unique diagnostic role.

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