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

Annotations already indicate read-only, idempotent, non-destructive behavior. The description adds useful return contract details (status, models, version), which helps an agent understand what the tool will report. No side effects or edge behaviors are hidden, and there is no contradiction with annotations.

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 with the core purpose, followed by a structured return summary. Every sentence contributes useful information, and the formatting makes the return keys easy to parse.

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 health-check tool with rich annotations, the description is complete. It specifies the operation, the returned fields, and their general meaning, which compensates for the lack of an output schema. No critical calling information 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 has zero parameters, so the baseline of 4 applies. The description correctly focuses on behavior and return values rather than inventing parameter documentation. There is nothing further an agent needs to know about inputs.

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 ('Check'), a clear object ('health status of Image API services and loaded models'), and distinguishes itself from the sibling tools, which are all content-processing operations rather than service inspections. The intent is unmistakable.

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 communicates a clear use context: this is a health-check tool for image services and models, so an agent can infer it should be used to verify readiness or diagnose service state. It does not explicitly name alternatives, but no sibling tool offers a health-check function, so no exclusion is necessary.

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