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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description repeats 'Read-only' but does add useful behavioral context by saying it returns status, progress, and available download artifacts; it does not discuss auth, rate limits, or polling behavior.

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 short sentences with the core purpose front-loaded. 'Read-only' is redundant with annotations but does not create clutter significant enough to reduce conciseness.

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 single-parameter read-only getter with rich annotations and an output schema, the description is largely complete: it states the returned information and safety profile. The main remaining gap is that it does not explain how to obtain the renderId or whether callers should poll.

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%, and the sole required parameter renderId is never named or explained in the description. The phrase 'existing screenshot render job' gives a broad sense of what the ID refers to, but not enough to compensate for the missing schema 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 names a specific verb and resource: it returns status, progress, and download artifacts for an existing screenshot render job. The word 'existing' distinguishes it from sibling creation tools like render_screenshots, and 'download artifacts' distinguishes it from list/view screenshot tools.

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?

Usage is implied by 'existing screenshot render job': the agent should use it when it already has a render job to inspect. However, the description does not explicitly mention when to use this versus render_screenshots, list_screenshots, or view_screenshot, nor does it explain where the renderId comes from.

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