Check store credentials

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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering the safety and scope. The description adds the detail that it checks credential validity, which is behavioral context. However, it does not disclose any side effects, rate limits, or failure modes beyond that. With annotations already carrying the main safety profile, the description adds moderate value but not extensive transparency, justifying a 3.

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 two concise sentences. The first sentence states the core purpose, and the second provides a direct usage directive. No filler words, no redundancy, and the most important information is front-loaded. It is a model of efficiency.

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 an output schema present, the description covers the purpose and when to call it. It does not elaborate on what the report contains, but that is handled by the output schema. The only minor gap is not specifying what qualifies as 'something returns nothing,' but that is likely context-dependent and not critical. Overall, it is sufficiently complete for correct invocation.

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 coverage is 100% by definition. The description doesn't need to explain parameters. According to the rubric, a tool with 0 parameters gets a baseline of 4, and the description does not introduce any confusion, so this score is warranted.

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 the tool reports which stores are configured and whether credentials work, which is distinct from the sibling tools that list apps, get app details, releases, or reviews. The verb 'report' plus the resource (stores and credentials) makes the purpose unambiguous.

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 usage instruction: 'Call this first when something returns nothing.' This tells the agent when to invoke it, but it does not mention any alternatives or when not to use it. Since the tool is unique among siblings, the guidance is adequate but not exhaustive, so a 4 is appropriate.

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