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

The annotations already declare readOnlyHint=true and destructiveHint=false, so the description builds on that by explicitly stating 'Read-only and spends no quota' and explaining URL expiration behavior: 'Download URLs returned by the render tools are signed and expire after an hour.' This adds critical context beyond the annotations.

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 front-loaded with the primary purpose and includes a clear use case explanation. It is slightly longer than necessary (about 4 sentences), but each sentence adds unique value: purpose, use case, expiration behavior, return type, and identification guidance. No redundant statements.

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 that there is no output schema and the tool is simple (two optional parameters), the description fully documents the return format, pagination behavior, and authentication-related side effects (URL expiration). It covers everything needed for an agent to use the tool effectively without gaps.

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 100%, so baseline is 3. The description adds semantic value by explaining that pagination defaults to page 1 (most recent renders) and that page_size defaults to 20. However, it doesn't further enrich the parameter meanings beyond what the schema already provides, so a 4 is appropriate for slight contextual addition.

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 starts with 'List the documents this account has already produced, newest first,' which is a specific verb plus resource. It clearly distinguishes from siblings like get_render (which retrieves a single render) and extract_from_render (which processes a render).

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 explicitly tells when to use this tool: when you need to find a PDF whose URL has expired ('a link from earlier in the conversation is probably dead'). It identifies the alternative sibling (get_render) and explains the workflow: find the render here, then get a fresh URL with get_render. It also states that the `name` field is the fastest way to identify the document, aiding selection.

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