xhs_login

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

Without annotations, the description discloses key behaviors: opens browser window, requires QR code scanning, persists login state to local storage. It does not cover failure scenarios but provides sufficient transparency for a login tool.

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 sentences, no unnecessary words. First sentence states the core action, second clarifies when to use, third explains behavior persistence. Highly efficient.

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?

Given existence of output schema (not shown but present), the description covers all essential aspects: purpose, first-time usage, persistence, and parameter constraint. No gaps for a simple login 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 description coverage is 100% (headless parameter explained in input schema). The main description adds no extra meaning beyond the parameter's own description, so baseline score of 3 applies.

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?

Description clearly states the tool opens browser window, scans QR code to log in to Xiaohongshu. It distinguishes from sibling tools (check_login, publish_note, search_feeds) by focusing on the login action. The phrase '首次使用必须调用' adds specificity.

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?

Explicitly mentions '首次使用必须调用' (must be called on first use) and that after login, state is saved locally so subsequent calls are unnecessary. The parameter description adds constraint that headless must be false for login. However, no exclusions or alternative tools are mentioned.

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