read_evidence

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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds genuine behavioral content about the return payload (version, page order, raw coordinates, recognition doubts) and a scope caveat about single snippets not constituting full context.

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?

Two short, front-loaded sentences with no filler: the first enumerates the returned facets, the second states the key limitation. Efficient, though terse enough that some useful context is omitted.

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, the description carries the burden of describing return values and does so by listing the fields returned. For a single-parameter read-only lookup it is nearly complete, missing only a hint about what evidence_id refers to or where such IDs originate.

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 0% and the description never mentions evidence_id, so it adds nothing beyond the schema. However, with a single self-explanatory required identifier, the gap is minor and the baseline of 3 fits.

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+resource: read the accurate citation snippet, and enumerates what comes with it (version, page order, raw coordinates, recognition doubts). This distinguishes it from generic siblings like read_page/read_document, though it never names an alternative 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?

The only usage guidance is the caveat '单片段不证明完整上下文' (a single snippet does not prove the full context), which warns about interpretation but does not say when to use this tool versus read_page, read_document, or build_evidence_pack. No preconditions or exclusions are given.

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