Verify credentials and upstream reachability

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

Annotations cover safety (readOnly, idempotent, openWorld), and the description adds meaningful context beyond them: it never returns the credential, it reports which source supplied it, the round-trip time, and a plain-English failure classification distinguishing missing vs. rejected credentials vs. server-side problems.

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?

A single front-loaded paragraph that answers what, how, what it reports, and when to call it. Minor waste in repeating the full hostname 'api.appstoreconnect.apple.com' three times, which could be shortened after first mention.

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?

With no input parameters and no output schema, the description carries the return-value burden itself and does so: it enumerates what is reported and how failures are categorized. Nothing an agent needs to call this correctly 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 takes zero parameters, so there are no parameter semantics to document. Baseline 4 applies; the description correctly implies no input is required.

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?

States a specific verb and resource chain: resolve the credential, then make one authenticated request to api.appstoreconnect.apple.com. This is unambiguous against siblings like list_apps or get_build, which are all data-retrieval tools; this one is purely diagnostic.

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?

Provides a clear trigger condition: 'Call this when a real tool fails and you want to know which hop broke.' That is strong contextual guidance, though it doesn't explicitly name when-not to use it or point to an alternative diagnostic.

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