screen_stream

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

No annotations are provided, so the description carries the behavioral burden. It discloses that polling returns a sliding window of the last few frames (oldest→newest), implies persistence, and mentions the stop action to end the stream. It does not detail side effects or cleanup beyond stopping, but the key behavioral aspects are covered.

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 a single dense sentence that front-loads the purpose and then explains each action. It uses parentheses effectively to clarify the poll behavior. It is concise without wasting words, though the lengthy sentence could be slightly more scannable.

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?

The description covers the three actions and the polling semantics in detail. It does not describe the exact return format (e.g., binary image data or URLs) or error conditions, but given the tool's complexity and the absence of an output schema, it provides enough for an agent to use it correctly for typical streaming scenarios.

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 each parameter. The description adds significant meaning to the 'action' parameter by explaining the semantics of each value and the sliding-window behavior. For 'device' and 'format', it adds little beyond the schema, but the core parameter is well elaborated.

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 verb (start, poll, stop) and the resource (persistent screen stream). It distinguishes from siblings like screenshot, which is a one-time capture, by emphasizing the persistent nature and the sliding-window polling behavior.

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?

The description explicitly instructs when to use each action (start, poll, stop) and provides context for poll being called repeatedly to watch self-changing screens. It does not explicitly name alternatives (e.g., screenshot) or state when not to use the tool, but the action-specific guidance is clear and actionable.

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