Render the featured cover

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

With no annotations, the description carries full burden. It discloses the resolution (1200x630) and return type (file path), but omits critical behavioral traits: side effects (file creation), permissions, error handling, performance, or file format. The description is insufficient for safe agentic use.

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 a single, dense sentence that front-loads key information (resolution) and covers core elements. It is concise without being vague. However, it could benefit from breaking into multiple sentences for clarity.

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 no annotations, no output schema, and 5 parameters, the description should be more comprehensive. It mentions output but not file format, naming conventions, or whether it overwrites. The tool's complexity (image rendering) warrants richer context.

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 80%, so baseline is 3. The description mentions 'headline with one word in accent colour' which maps to title and highlight, but adds no new parameter semantics beyond what the schema already provides. No improvement over 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 clearly states what the tool does: renders a 1200x630 featured/hero cover with specific elements (wordmark, shapes, headline). It also mentions the output (returns file path). However, it does not explicitly distinguish from sibling tools like render_figure or render_set, which may have overlapping purposes.

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 no guidance on when to use this tool versus alternatives. There are no when-to-use or when-not-to-use statements, and no mention of prerequisites or context. This is a significant gap for an AI agent deciding between render_cover, render_figure, or render_set.

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