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

Annotations already declare readOnlyHint=true and openWorldHint=true, lowering the bar. The description adds behavioral specifics: 'newest first' ordering, inclusion of status and template version, and signed URLs only for successes, plus the note that it is 'Free.' These go beyond the annotations and help an agent understand what the call returns and its side-effect-free nature.

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 sentences with no wasted words. It front-loads the primary function and ordering, then adds practical use cases and a cost note, all in a compact, scannable format.

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 simple tool with one optional parameter, read-only annotations, and no output schema, the description covers the essential information: what is returned, ordering, and when to use it. It does not mention response format details (e.g., array shape) or pagination beyond the limit, but those are minor given the tool's simplicity.

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 100%—the schema fully documents the 'limit' parameter with min, max, and default. The description does not add any new meaning to the parameter; it simply omits it. Per the rubric, a baseline of 3 is appropriate when the schema carries the parameter documentation.

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 lists recent renders on the account, ordered newest first, and specifies the included fields (status, template version, signed URL for successes). It also distinguishes itself from siblings like get_render (which fetches a specific render) and render (which creates one) by its listing focus and explicit use cases.

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 concrete usage scenarios ('finding a render whose id you lost' and 'checking what a batch did'), which tells an agent when to choose this tool. It does not explicitly name alternatives or state when not to use it, but the context is clear enough for correct selection among siblings.

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