rnw_screenshot

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

With no annotations, the description carries the full behavioral burden. It usefully discloses the return type ('base64-encoded PNG image that can be viewed by AI agents'), which is valuable since there is no output schema, but it omits prerequisites such as whether the page must be loaded or if rnw_wait is needed, and gives no timing or size-limit context.

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 tight sentences, front-loaded with the action and followed by the return value. No filler, though the second sentence could have been spent on sibling differentiation instead of restating the obvious image format.

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 two-parameter capture tool with no output schema, the description adequately covers the action and return format. It stops short of the two things an agent most needs: how it differs from rnw_snapshot and any precondition (page readiness, waiting) before capturing.

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 both parameters are already fully documented in the schema. The description's phrase 'current page or a specific element' only echoes the schema's selector/fullPage semantics without adding format, default, or interaction detail; baseline 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 gives a specific verb and resource: 'Take a screenshot of the current page or a specific element.' It clearly conveys the operation, but it never distinguishes itself from the sibling rnw_snapshot, which is the critical ambiguity an agent must resolve when choosing a capture tool.

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?

There is no when-to-use or when-not-to-use guidance, and no alternative is named despite rnw_snapshot and rnw_evaluate being plausible substitutes. The agent must infer from the tool name alone when a screenshot is preferable to a snapshot.

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