mm_describe_image

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

Annotations already cover read-only safety (readOnlyHint, idempotentHint, destructiveHint). The description adds valuable behavioral context beyond annotations, such as input format restrictions and the return type (Markdown text), which is useful for the agent.

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 concise and well-structured with clear sections (summary, Args, Returns). Every sentence adds value, and the main purpose is front-loaded, making it easy for the agent 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?

Given the low complexity (2 simple params) and existing output schema, the description is complete: it includes purpose, parameter semantics, return type, and input constraints. No critical information is missing 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?

Schema description coverage is 0%, making the description's Args section essential. It explains image_path with absolute path and supported formats, and prompt as optional with a concrete example, fully compensating for the lack of schema descriptions.

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 analyzes local images and returns text descriptions, using a specific verb+resource+output structure. It distinguishes itself from sibling tools by specifying 'image' as the media type, differentiating from audio/video tools.

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 provides clear context on when to use the tool by specifying it works with local image paths and supported formats (PNG/JPEG/WebP/GIF). It implies exclusions (e.g., remote URLs, unsupported formats) but does not explicitly name alternatives or when-not-to-use conditions.

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