rag_stats

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

No annotations exist, so the description must carry the behavioral load. It does disclose the shape of what is returned (all metrics, read-only inspection implied), which is the main behavioral fact needed for a zero-parameter tool, but it never states that the call is side-effect free, whether it is expensive on large indexes, or what an empty/unbuilt index returns.

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 with the purpose first and the returned fields after a colon. No filler, nothing that fails to earn its place.

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?

With no output schema and no annotations, the description usefully compensates by listing the return values, which is the key gap for a stats tool. What remains missing is a note on the read-only nature and on behavior when no index has been built.

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 at all, so there is nothing for the description to disambiguate; the baseline for zero-param tools applies. The enumerated return fields are a bonus rather than parameter documentation.

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 gives a specific verb-plus-resource ("查看索引状态") and then enumerates exactly what status fields are exposed: total chunks, text volume, per-source chunk counts, and last build time. This clearly separates it from rag_index (which presumably builds) and rag_search, though it never names those siblings explicitly.

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: an agent can infer this is the tool to call when it needs to inspect index health or readiness before searching. There is no explicit statement of when to call it instead of rag_index or rag_search, and no preconditions (e.g. whether an index must already exist) are given.

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