sign_screenshot_url

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

Annotations already declare readOnly/openWorld/non-destructive, so the safety bar is low. The description adds genuinely useful behavior beyond that: signing is free while rendering consumes one credit, and URLs expire after the specified duration — a cost/expiry model the agent would otherwise not know.

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?

Four short sentences, front-loaded with purpose before use cases and the billing/expiry nuance. No sentence is wasted.

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 full schema coverage and annotations covering the safety profile, and no output schema to explain, the description covers purpose, use context, and cost/expiry. Only the sibling-routing guidance is thin.

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% across all 15 parameters, so the schema already documents every input. The description only alludes to the expiry duration ('specified duration') without adding format or syntax beyond expires_in. Baseline 3 is correct.

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 (generate/sign) and resource (screenshot URL) and immediately names the property that distinguishes it from take_screenshot: the URL works 'without an API key'. An agent can tell it apart from its siblings without opening the schema.

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?

Gives clear use cases (embedding in emails, documents, sharing with third parties), which is real when-to-use guidance. However it never explicitly contrasts with take_screenshot or check_screenshot_cache, so the routing decision is left partly to inference.

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