vision_describe

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

No annotations are provided, so the description carries the full burden. It discloses the core behavior (reading a local file and returning a vision-based interpretation) and implies a non-destructive read operation. However, it doesn't mention potential limitations such as unsupported formats (covered in schema), file size constraints, or behavior when the file is missing, leaving some gaps.

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 no superfluous content. The first sentence identifies the action and outcome, the second gives a concise usage directive. It is well-structured and front-loaded.

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 simple read-only tool with two optional parameters and no output schema, the description adequately covers purpose and usage. The schema handles parameter details. The output is hinted as 'what a vision-capable model sees/understands' but not fully specified, which is a minor gap. Overall, it is complete enough for an agent to invoke correctly.

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 input schema provides 100% coverage with clear descriptions for both 'question' and 'image_path', including default behavior for the latter. The tool description does not add additional meaning beyond the schema, so the baseline of 3 is appropriate.

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's function: 'read a local image file and return what a vision-capable model sees/understands about it.' It uses a specific verb ('read') and resource ('local image file'), making the purpose unambiguous. Since there are no sibling tools, distinguishing is not needed, but the description stands on its own.

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 says 'Use whenever you need to see or interpret an image' and provides examples like screenshots, diagrams, and photos. This gives clear context for when to use the tool, though it doesn't mention alternatives because none exist. It's a straightforward usage instruction without exclusions.

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