preview_render

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

Annotations already mark the tool read-only, and the description adds useful behavioral context beyond that: it produces actual PNG pixels, includes overflow/font diagnostics, and depends on a prior setup-export call. No annotation contradiction exists.

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?

Two tight sentences front-load the primary action and output, then add the prerequisite and usage timing. Every sentence earns its place with no filler or redundancy.

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 3-parameter, read-only preview tool without an output schema, the description covers the main action, return-like output, diagnostics, setup prerequisite, and intended usage point. It does not specify failure behavior if setup-export was skipped, but the provided context is sufficient for correct invocation in the common case.

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%, so the description must compensate. It does clarify that 'revision/page' are the core inputs and that the revision is a saved revision, but it does not explain the required documentId parameter or the optional nature of pageId. It partially compensates for the schema gap, but not fully.

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 uses a specific verb ('Render') and a specific resource ('saved revision/page'), and clearly states the output ('real PNG pixels plus overflow/font diagnostics'). It also distinguishes this tool from export by framing it as a pre-export inspection step, so an agent can tell it apart from document_export and similar siblings.

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?

'Inspect the image before export' gives clear usage context, and 'Requires setup-export once' states a concrete prerequisite. It does not explicitly name alternative tools or say when not to use it, but the before-export framing provides enough guidance for selection.

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