Start recording

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

Beyond the annotations, it discloses meaningful behavior: settings are pulled from the user's saved Recordful config (mode, microphone, camera, countdown), that the promise resolves once capture is actually live, and that it reports failure reasons. Annotations only carry safety hints, so this additional state-machine context is genuinely valuable; it stops short of 5 only because it doesn't mention permissions or rate/side-effect details.

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 short sentences, front-loaded with the action and resource, followed by resolution semantics and the sequencing precondition. Every sentence earns its place with no filler.

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 no-required-parameter action tool with full schema coverage and safety annotations, the description covers what it does, what config it applies, how it resolves, and when to call it. It could be more complete by noting what happens on an already-recording tab or linkage to pause/stop, but it is essentially sufficient to invoke correctly.

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 both parameters (tabId, timeoutMs) are fully documented in the schema, making the baseline 3 appropriate. The description adds only indirect context (settings come from saved config) without clarifying parameter behavior beyond the schema.

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?

States a specific verb and resource ('Start a Recordful recording on the target tab') and distinguishes itself from siblings by naming the state transition it performs versus stop_recording/pause_recording/resume_recording. An agent can route to the correct tool from the description alone.

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?

Gives a clear prerequisite/precondition for success ('Navigate to the page you want to show before calling this'), which explains when and how to sequence this against the navigate sibling. It does not explicitly name when not to use it or point to alternatives, so it stops short of 5.

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