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

The annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered structurally. The one genuinely additive behavioral claim is '不扣次数' — the call has no quota cost — which is not expressed in any structured field. Beyond that, freshness/latency of the returned metadata and the response shape are undisclosed.

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 compact sentence with the payload (what metadata is returned) first and the cost qualifier second. Nothing is repeated and no words are wasted.

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, read-only tool with no output schema, naming the four returned categories (data source, time window, coverage, limits) plus the billing behavior gives an agent enough to decide whether the response answers its question. It falls short of complete only in not stating how the metadata should influence subsequent calls.

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 no parameters, so there is nothing for the description to disambiguate; the baseline of 4 applies. No misleading hints are given 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?

The description names a concrete resource set — real-time data provenance (数据来源), time window (时间口径), coverage and limits (覆盖与限制) — so an agent knows this returns metadata about the data rather than the data itself. It is not explicitly distinguished from the adjacent sibling get_access_status, which is the only thing keeping it below 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 only implied: '不扣次数' signals the call is free, which encourages calling it before expensive analysis, but there is no explicit 'call this when...' or 'do not use this for...' statement. The overlap with get_access_status (access/entitlement) versus this tool (data coverage/limits) is left for the agent to infer.

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