start_screen_recording

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

With no annotations, the description must carry behavioral disclosure. It does reveal platform-specific mechanisms (WDA MJPEG via ffmpeg for iOS, adb screenrecord for Android), which adds useful context. However, it omits important behaviors such as output file handling, permission requirements, or that recording continues until stopped. Score 3 reflects partial coverage.

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 extremely concise: one clear purpose sentence followed by platform-specific details. No wasted words, front-loaded with the primary action.

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?

Despite having an output schema, the description lacks critical context for a recording operation: how to stop recording (though sibling exists), where files are saved, device selection requirements, and potential side effects. The platform details are helpful but not sufficient for a complete operational picture.

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 0%, and the description does not explain the 'device' or 'filename' parameters at all. No guidance on device identifier format, filename defaults, or allowed values. This is a significant gap for a tool with only two parameters.

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 'Start recording the device screen' with a specific verb and resource, distinguishing it from siblings like stop_screen_recording and screenshot. The platform details reinforce the purpose without ambiguity.

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 provides no explicit guidance on when to use this tool versus alternatives like screenshot or stop_screen_recording. It mentions platform-specific implementation but does not suggest usage context or exclusions.

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