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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds context about inline HTML input and default dimensions, but does not disclose potential behavioral traits like external resource handling or return format. This matches the baseline for annotation-backed tools.

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 clean sentences: the first front-loads the action and defaults, the second provides the use case. There is no filler or redundant information, so every sentence earns its place.

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 (3 params, no output schema), and annotations cover safety. The description adequately covers purpose, use case, and defaults, but in the absence of an output schema it does not specify the return value format (e.g., image URL vs binary data), which is a minor gap.

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 description coverage is 100%, with detailed descriptions for html, width, and height including ranges and defaults. The description's mention of 'defaulting to the standard 1200x630' just reiterates schema defaults, adding no extra semantic value beyond the schema.

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 states a specific verb+resource: 'Render an inline HTML snippet to a social-share (Open Graph) image'. It clearly differentiates from sibling tools like render_pdf or screenshot_url by targeting OG image generation and specifying the 1200x630 default dimensions.

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 when-to-use context: 'Use this to generate og:image assets for blog posts, products, or share cards'. However, it does not explicitly mention alternatives or when not to use it, so it stops short of full guidance.

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