sequence_start

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

Beyond annotations (destructive, open-world), the description adds behavioral details such as immediate return, best-effort timing, and the requirement for balanced pairs, giving a fuller picture of what happens when called.

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?

Each sentence delivers a distinct piece of information without redundancy, making it concise and well-structured for quick comprehension.

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?

It covers key operational aspects (start, constraints, return behavior, timing reliability) and mentions related tools for follow-up (browser_status, sequence_stop), making it fairly complete for an agent to decide and 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?

The description clarifies the meaning of atMs (absolute offset from start, max 30s) and explains ordering for equal timestamps, adding value beyond the raw schema which only lists types and ranges.

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 tool starts a sequence of timed key events, with specifics like absolute offsets, max duration, and overlap capability, distinguishing it from siblings like key_down or key_up.

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 provides some usage constraints (balanced down/up pairs, no holds, immediate return) and mentions inspecting browser_status or stopping with sequence_stop, but does not explicitly contrast with alternatives like key_down or chord for when this tool is preferred over them.

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