Check WeChat Official Account login

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

Annotations already cover read-only, open-world, idempotent, and non-destructive behavior. The description adds meaningful context beyond annotations: the cookie is locally stored, only non-secret status is returned, and cookies must not be passed as arguments. This clarifies the tool's security and privacy posture.

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?

The description is three short sentences, front-loaded with the main verb and purpose, and contains no fluff. Every sentence earns its place: purpose, when to call, and a critical security warning.

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 simple auth-check tool with rich annotations, the description is mostly complete: it states what is validated, what is returned, when to call it, and a key constraint. The only minor omission is what an invalid/expired cookie returns, but the high-level return description and the tool's straightforward nature keep this sufficient.

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 single optional response_format parameter is fully described by the schema with an enum and default value, so the agent can invoke the tool correctly without additional description. However, the description does not mention this parameter at all, giving 0% schema description coverage; since the parameter is trivial and optional, this is not a serious gap.

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 validates a locally stored WeChat cookie and returns non-secret session/account status. This distinguishes it from sibling tools that read articles, reports, or account info, making it a dedicated auth preflight check.

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?

The description explicitly says 'Call this first before backend reads,' providing clear when-to-use guidance. The warning 'Never pass a cookie as an argument' is a useful negative instruction, though it does not name alternative tools because none exist for this purpose.

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