image_understand

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

With no annotations, the description carries full burden. It discloses that the backend provider/model is fixed by server admin, that local file paths are unsupported due to containerization, and that the return is a text description. These are meaningful behavioral traits beyond the basic operation.

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 front-loaded with a clear purpose, then logically organized with usage, args, and returns. Every sentence adds necessary information—even the container explanation is essential for preventing misuse. No redundancy.

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?

The tool is simple (2 params, no annotations) and the description covers its operation, usage context, parameter details, constraints, and return value. The output schema is also described in text, making the tool's behavior fully specified.

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 schema descriptions are absent (0% coverage). The description compensates thoroughly by explaining that 'image' accepts http(s) URLs or base64 data URIs, explicitly excluding local paths and why, and describing the 'prompt' parameter's default behavior when empty.

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 explicitly states 'Describe or analyze an image using a vision model' and adds 'Call this whenever you need to understand an image you cannot see.' This gives a clear verb and resource, making the purpose unambiguous even without sibling comparisons.

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?

It provides direct usage guidance: 'Call this whenever you need to understand an image you cannot see.' It also explains a key limitation (local file paths not supported) and how to work around it, giving practical when-to-use context.

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