Verify credentials and upstream reachability

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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, so the safety profile is covered. The description adds valuable behavioral context beyond annotations: it resolves the credential the way real tools do, makes exactly one authenticated request, reports the credential source, and never returns the credential itself. It also explains the plain-English hint categories. This is strong added context, though it doesn't detail error formats or timeouts.

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 compact and front-loaded: it opens with the core action, then details the outputs, then gives the usage trigger. Every sentence adds information; no filler or repetition of the title.

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 diagnostic tool with rich annotations and a clear output description, the description is complete. It tells the agent what the tool does, what it reports, what it never does, and when to call it. No output schema exists, but the description enumerates the reported items sufficiently.

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 there is no parameter schema to document. The description fully explains what the tool does with its implicit inputs (credential resolution, upstream request). Baseline 4 is appropriate for a zero-parameter tool.

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 states a specific verb ('Resolves', 'makes one authenticated request') and resource (api.freshbooks.com), and clearly distinguishes this healthcheck tool from the data-access siblings. It explains what it reports (credential source, acceptance, round-trip time, hint) and explicitly says it is read-only.

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 gives an explicit when-to-use instruction: 'Call this when a real tool fails and you want to know which hop broke.' It also implies when not to use it (not for normal data operations) and distinguishes it from siblings by focusing on credential/upstream diagnostics rather than resource access.

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