live_screenshot

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

With no annotations provided, the description carries the full burden of disclosing behavior. It explains the target tab selection logic (pinned vs active), the JPEG format, and the requirement of an open, connected side panel. It does not mention error handling or return format, but for a read-only screenshot tool this is largely sufficient. A small gap is the absence of any caveat about what happens if the side panel is not connected, though the requirement statement implies failure.

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, front-loaded with the core purpose, then usage guidance, then a prerequisite. There is no redundancy or fluff; every clause earns its place.

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 4-parameter tool with no output schema and no annotations, the description covers the core purpose, target selection, usage guidance, and a key prerequisite. It does not describe the exact return format (though 'JPEG screenshot' implies an image) or potential errors, but these are minor given the tool's simplicity and the completeness of the parameter schema.

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 the schema already documents all four parameters (project, quality, session, fullPage). The description adds no additional parameter-level semantics beyond what the schema provides. Per the rubric, the baseline is 3 when schema coverage is high, and the description does not enhance it.

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 states a specific action (capture a JPEG screenshot) and a specific resource (the side panel's target tab, with a clear definition of which tab that is). It also differentiates itself from the sibling live_snapshot by explicitly contrasting use cases, so an agent can immediately tell them apart.

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?

It explicitly says to prefer live_snapshot for selector-finding and to reach for this tool when the question is genuinely visual (layout, colors, rendering). It also states a prerequisite: the side panel must be open and connected. This gives clear when-to-use and when-not-to-use guidance.

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