render_preview

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

With no annotations at all, the description carries the full burden and does well: it discloses the PREVIEW watermark, that no credits are consumed, that pdf/png are written to a local file whose path is returned, that png covers only page 1, and that show=true additionally returns the image. What it omits is whether a template_id is required for saved-template rendering or what happens on failure.

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?

Three sentences, front-loaded with the watermark/no-credit constraint, then output-mode mechanics, then the iterate workflow. Parenthetical asides are dense but every clause carries 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?

With nine optional parameters at 0% description coverage, no annotations and no output schema, the definition covers the core render contract (source, output fidelity, what gets returned) but leaves the personalization parameters (mapping, record_id, language, timezone, model) entirely unexplained. Adequate for a simple preview, thin for the full surface it exposes.

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% across nine parameters, so the description must compensate and mostly doesn't. It explains template_id, output and show, and alludes to 'layout', but says nothing about model, mapping, language, timezone or record_id — five parameters an agent would be guessing at.

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?

States a specific verb and resource (render a preview of a saved template or an unsaved layout) plus the three output modes, so the agent knows exactly what the call produces. It does not differentiate itself from the nearby preview_starter and preview_email siblings, so an agent must infer the routing itself.

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 trailing clause ('look at it to judge the design ... and iterate') implies the intended design-review workflow, but there is no explicit when-to-use/when-not statement and no mention of preview_starter, preview_email or validate_layout as alternatives. Usage is suggested rather than prescribed.

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