credential_status

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

With no annotations, the description must carry the behavioral burden, and it does disclose something genuinely non-obvious: results are not purely vault-cached, the platforms are queried upstream to fill fields like netease's uid that a cookie import leaves blank. That implies network calls and possible latency/failure, but the description never says whether this is strictly read-only, whether it can mutate stored credentials, or what happens when a platform is unreachable.

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 core purpose is front-loaded in the first sentence and the second sentence earns its place by explaining the upstream-completion behavior. The mixed English/Chinese phrasing is slightly harder to scan but adds 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?

An output schema exists, so return values need not be described, and with zero parameters the surface is small. The description covers scope and the upstream-completion caveat, leaving only the read-only/auth-refresh question open, which is a minor gap for a status-check 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?

The tool takes zero parameters, so there is no parameter semantics to explain and the baseline of 4 applies. Nothing in the description misleads about inputs.

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 — 'Check every platform's credential status' — and enumerates the covered platforms (qq_music / netease / kugou), so an agent knows the scope is all platforms at once. It is distinguishable in spirit from credential_refresh or credential_logout, but it never names those siblings to make the contrast explicit.

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?

There is no statement of when to call this versus credential_refresh, login_methods, or credential_set_cookie, and no preconditions or follow-up actions are given. The second sentence describes what the tool does internally rather than when an agent should reach for it, leaving usage to inference from the name alone.

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