douyin_login_start

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

With no annotations, the description carries the full burden, and it does disclose important traits: a headed (visible) Chrome window is launched and human QR-scan interaction is required. It omits whether the call blocks until login completes, what happens if a session already exists, and any timeout/failure behavior.

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?

A single front-loaded sentence that states the mechanism, the user action, and the target service with no filler. Nothing redundant or 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?

For a zero-parameter trigger the description covers the core action and the human-in-the-loop requirement, but with no annotations, no output schema, and no mention of how login success is confirmed (the role of douyin_login_status), it is not fully complete for the flow.

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 tool takes zero parameters, so per the baseline there is nothing for the description to disambiguate. No parameter-level detail is missing.

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 states a specific verb-and-resource action (opens a headed Chrome window to authenticate to Douyin) and makes the mechanism concrete (QR scan). It does not explicitly distinguish itself from the sibling douyin_login_status, so it falls short of a 5.

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?

Usage is implied: the agent can infer this is the entry point for authenticating when not logged in. However, it never says when to call it versus douyin_login_status (i.e., that status should be polled after this call) and states no prerequisites such as 'requires a user present at the machine'.

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