Verify credentials and upstream reachability

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=true. The description substantially enriches this by disclosing that it resolves credentials the same way real tools do, makes exactly one authenticated request, reports round-trip time, distinguishes failure modes, and never returns the credential itself. This exceeds annotation coverage and clearly communicates behavioral safety.

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 with zero waste. The first sentence states the core action, the second enumerates output details, and the third gives usage guidance. Each sentence earns its place and the most important information is front-loaded.

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 diagnostic tool, the description covers all essentials: what it does, what it reports, when to use it, and its safety behavior. No output schema exists, but the description's enumeration of reported values is enough for an agent to interpret the result 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 and the schema covers 100% by having no properties. The baseline for zero parameters is 4; the description confirms no input is needed by focusing on what it performs. This is appropriate since there is nothing to explain beyond the schema.

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') with a concrete resource ('mobile-api.zola.com') and exact outputs ('which source supplied the credential', 'accepted it', 'round-trip time', 'plain-English hint'). It clearly differentiates this diagnostic tool from the 80+ sibling tools that perform CRUD or search operations, leaving no ambiguity about what it does.

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 says 'Call this when a real tool fails and you want to know which hop broke,' giving a clear invocation context. It doesn't list when-not-to-use or name alternative diagnostic tools, but none exist among the siblings—this is the only healthcheck—so the context is sufficient without exclusions.

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