Render HTML/CSS via Satori

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

With no annotations provided, the description fully discloses behavioral traits: text becomes vector paths (not editable text nodes), CSS gradients and rgba() are unsupported, font fetching adds latency, and the syntax is JSX-object based. It also explains the execution context (iframe, available satori function) and the need to fetch a font first, going well beyond what structured data could indicate.

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 well-structured with a purpose statement, usage guideline, a clearly labeled 'LIMITATIONS' section, and a brief execution note. Every sentence adds necessary information; there is no redundancy or filler. The use of sections and bullet-style limitations improves scannability.

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 tool with no output schema, the description covers key prerequisites (font fetching), syntax (JSX objects), execution environment (iframe, satori function), and limitations (text paths, no gradients, no rgba). It clearly states the outcome ('editable Figma vector nodes') and provides enough detail for an agent to use the tool correctly, despite not describing the exact return value beyond the script returning an SVG string.

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 description adds meaningful context for the script parameter by explaining how to write it: 'Use the satori() function with JSX-like objects' and 'Must fetch a font first: fetch Inter WOFF, pass as fonts array.' While x/y parameters lack explicit descriptions in both schema and description, the overall guidance for the most complex parameter compensates given moderate schema coverage (67% of parameters have 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 renders HTML/CSS layouts as editable Figma vector nodes via Satori, using a specific verb and resource. It differentiates from siblings by explicitly pointing to render_d3 for data viz and focusing on complex CSS layouts that are hard to express in SVG.

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?

Explicit usage criteria are provided: 'Use ONLY when you need complex CSS layouts that are hard to express as SVG' and 'For data viz, prefer render_d3 instead.' The limitations section (e.g., text as paths, no gradients) further helps an agent decide when this tool is appropriate.

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