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

With no annotations, the description carries the full burden, and it does disclose useful behavior: the return includes severity and an item-9 warning, and the tool is explicitly non-diagnostic. It does not cover input validation (exactly 9 values in 0–3), out-of-range handling, or error behavior.

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 resource and scoring structure front-loaded, followed by the return behavior and a scope caveat. No filler, though the bracketed guide tag is slightly noisy.

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 adequately covers what the tool computes and roughly what it returns (severity, item-9 warning). Minor gaps remain around input constraints and error handling for a scoring utility.

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 0%, so the description must compensate, and '9 題 0–3 分' effectively documents the single `answers` parameter: nine numeric responses each on the 0–3 scale. This fills the schema gap well, short only of naming the parameter or stating it is required.

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 and resource: scoring PHQ-9 depression symptoms, with the 9-item 0–3 structure. Naming PHQ-9 distinguishes it from the sibling score_gad7 and score_mood_thermometer tools, though it does not name those alternatives 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 must infer that this is called when it has a completed PHQ-9 questionnaire. The caveat '不是診斷' (not a diagnosis) sets an important scope boundary but is not a when-to-use/when-not directive or an alternative routing hint.

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