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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description adds useful substance beyond that: the fixed count of 14 subjects, the curriculum-standard edition (2022, revised 2025), and the shape of the returned summary counts. No pagination or volume concerns exist for a zero-parameter tool.

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 sentences, front-loaded with the resource and the enumeration detail, with no filler. The bilingual duplication adds length without new information, but it is a minor cost.

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 must convey return shape, and it does at a summary level (subjects, stages, standards, key-point counts). For a simple zero-argument listing tool this is nearly complete; only the exact record structure is left unstated.

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 and the schema is a closed empty object, so there is nothing to disambiguate; the baseline for zero parameters applies. The description correctly avoids inventing parameter guidance.

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 specific verb and resource ('List the subjects' / 列出学科) and scopes it to the 14 compulsory-education curriculum-standard subjects with version info. It also states what is returned (stages, standards, key-point counts). It does not explicitly distinguish itself from sibling list_standards, which also enumerates items, so it stops short of 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?

The listing of stages/standard counts implies this is an overview or entry-point tool, but it never says when to use it instead of list_standards, search_standards, or get_standard. An agent must infer the routing from the noun 'subjects' alone.

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