Start recording

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

Annotations only say readOnlyHint=false and openWorldHint=false, so the description carries the burden and does it well: it discloses the significant side effect that enabling video reloads the page into a fresh recording context while preserving cookies and localStorage. That reload/reset behavior is exactly the kind of non-obvious consequence an agent must know before calling.

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?

Three tight sentences: purpose and captured artifacts first, the side-effect caveat second, and the required follow-up action last. No filler, and the important behavioral warning is front-loaded rather than buried.

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?

With two optional params, no output schema, and light annotations, the description covers what is captured and the required stop_recording follow-up. It doesn't state where artifacts are persisted or what happens if recording is already active, which is a minor remaining gap for a stateful capture tool.

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 coverage is 100%, so the baseline is 3, but the description adds real semantic value by explaining the consequence of the video flag (page reload into a fresh context). The name parameter is left entirely to its schema description, which is acceptable given full coverage.

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 names a specific verb and resource ('Start recording the browser session') and enumerates exactly what the recording contains: Playwright trace with DOM snapshots, network, console, optional video, and a tool-call log. It also names its paired sibling (stop_recording), so an agent can distinguish it from the other observation tools like take_screenshot or get_page_snapshot.

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 gives clear lifecycle guidance — 'Call stop_recording when done to save everything' — which tells the agent the necessary follow-up. It lacks an explicit when-not or comparison to alternatives (e.g., use take_screenshot for a one-off capture), which keeps it from a 5.

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