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

The annotations already declare readOnly, idempotent, closed-world, and non-destructive behavior, so the description does not need to repeat the safety profile. It adds real value beyond them: the results are produced by an AI that read each lesson's original text, each entry includes a quotation and page number, and when per-lesson results are missing it falls back to machine-aligned units; it also warns that everything is pending verification (都待核验). The main remaining gap is that the output shape is not described, but because no output schema exists, that gap is only partly forgivable.

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 Chinese sentence front-loads the core purpose and then adds the provenance and verification caveats efficiently. The trailing English fragment 'Textbook lessons and chapters for a standard' is a near-redundant restatement, though it is harmless. Overall it is tight, with only minor waste.

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 one-parameter read-only lookup with no output schema, the definition is nearly complete: it explains what is returned (lessons, quotes, page numbers, fallback units) and flags data reliability. What is missing is the response structure, such as paging or result ordering, but that is a small gap given the tool's simplicity.

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 coverage is 100% for the single parameter, and the schema already defines `code` as 标准或要点编码. The description's phrase 一条标准或要点 mirrors that wording, so it adds little new meaning about acceptable code formats or how to obtain a code. With a fully documented one-parameter schema, the baseline of 3 is appropriate.

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 states a specific verb and resource: it returns the textbooks and lessons in which a given standard or key point (标准/要点) is taught, and it names the textbook editions (人教版, 统编版). This distinguishes it from find_textbook_chapter, which works in the opposite direction (chapter to standard). It is clear, but the direction of the relationship is stated only implicitly rather than with an explicit sibling contrast.

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 implied by the single required input (a standard code), so an agent can infer that it should call this tool when it has a code and wants teaching locations. However, the description never states when to prefer this over find_textbook_chapter or search_standards, and it gives no prerequisites or exclusions. The guidance is therefore adequate at best, not explicit.

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