Screenshot the stage (JPEG)

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

With no annotations, the description carries the burden of explaining behavior. It discloses the re-encoding via sharp, the lossy nature, and the quality trade-off. It implies a return similar to 'screenshot' but does not explicitly state the return format, which is a minor gap given the reference to the sibling.

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 concise sentences front-load the key behavior (JPEG, smaller payload) and then provide the trade-off and parameter note. No redundant phrases; every sentence adds value.

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 and full schema coverage, the description is nearly complete. It relies on the sibling tool for return semantics but that is sufficient. The only omission is an explicit statement of the return type, which is inferred from the sibling.

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% and already describes the 'quality' parameter in detail (range, default, effect on size). The description only restates the parameter with no additional meaning, so the baseline of 3 is appropriate.

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 captures the same stage image as 'screenshot' but re-encodes it as JPEG for a smaller payload. It names the sibling tool and distinguishes by output format and size, leaving no ambiguity about what it does.

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?

Provides explicit guidance: 'Prefer this version unless you need pixel fidelity,' and explains the trade-off that JPEG is lossy and may soften fine UI detail and flat color edges. This clearly tells the agent when to use this tool versus the alternative.

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