api_status

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

No annotations are provided, so the description carries the burden. It discloses two key behaviors: it checks which credentials are present and whether a live API call succeeds. This implies read-only, non-destructive behavior, and it explicitly mentions making a live API call, which is relevant. However, it doesn't disclose the return format or any potential side effects (though 'diagnose' strongly implies non-mutating). It could be more explicit that it performs a network call and does not modify anything, but given the context, it is reasonably transparent.

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 sentences, with the core purpose front-loaded in the first sentence and the usage condition in the second. Every word earns its place, with no filler or redundancy. It is as concise as possible while conveying the essential information.

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 tool with an output schema (which declares the return shape), the description fully covers what the tool does and when to use it. There is no missing information an agent would need to invoke it correctly: it knows the purpose, the lack of inputs, and the appropriate trigger condition. The output schema handles return-value documentation, so the description is complete.

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 input schema is an empty object. The description adds no parameter information because there are none. Per the rubric, a tool with 0 parameters and 100% schema coverage receives a baseline of 4. The description correctly implies the tool requires no input, so no further semantic addition is needed.

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 uses a specific verb ('Diagnose') and a clear resource ('the MovieGlu connection'), and specifies what it checks (credentials present, live API call success). This clearly distinguishes it from the sibling tools, which are all data-fetching operations for movies, cinemas, and showtimes. A tool named 'api_status' could be ambiguous, but the description removes that ambiguity by naming the exact diagnostic function.

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 states 'Use when other tools fail.' This is a clear, actionable condition for selecting this tool over its siblings. It doesn't enumerate all non-use cases, but the primary use case is unambiguous. This meets the bar for explicit when-to-use guidance.

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