Generate alt text (vision)

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 that the tool uses a vision model and is LLM-backed, but lacks details on error handling, permissions, limitations (e.g., image size, accessibility), or what happens if both params are provided. Some behavioral context is added, but gaps remain.

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: the first states the purpose, the second provides usage instructions. It is front-loaded, efficient, and contains no extraneous 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?

The description covers core purpose and parameter usage, but lacks mention of the return value (alt text string) and error scenarios. Given no output schema and no annotations, some additional context about what the tool returns would improve completeness.

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 coverage is 100%, so baseline is 3. The description adds value by explaining the two mutually exclusive usage patterns (imageUrl vs. selector+pageUrl) and notes that local images require the selector+pageUrl approach. This clarifies when to use each parameter beyond the 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's function: 'Describe an image for an HTML alt attribute using a vision model.' It also distinguishes itself from siblings by claiming to be 'The ONLY LLM-backed tool.' This provides a specific verb-resource combination and differentiates it from other tools in the list.

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 gives clear usage context: 'Provide either imageUrl, or selector + pageUrl to locate an <img> on a page.' It explains two usage modes but does not explicitly mention when not to use the tool or reference alternative tools beyond the uniqueness claim.

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