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

With no annotations, the description carries the full burden. It usefully discloses return content (severity plus an item-9 warning, i.e. a suicidality flag) and a safety caveat that it is not a diagnosis. It does not disclose validation behavior (e.g. what happens if fewer than 9 values or values outside 0–3 are supplied), leaving error semantics undocumented.

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 compact clauses plus a short disclaimer; the scoring rule and the key warning are front-loaded with no filler. Every element earns 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?

For a one-parameter scoring tool with no output schema, the description covers input format, output content, and the clinical caveat. The main remaining gap is input validation/error behavior, which matters because a malformed answer array is easy to pass.

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 single parameter is an untyped-looking array of numbers. The description compensates well by specifying 9 items each scored 0–3, which is exactly the semantic the schema lacks. It stops short of naming the array parameter or mapping items to the nine PHQ-9 questions.

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 (scoring) and resource (PHQ-9 depression symptoms), and explicitly names the output domain (severity, item-9 flag). This cleanly distinguishes it from siblings score_gad7 and score_mood_thermometer, which are different instruments.

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 instrument name and the 'not a diagnosis' caveat, which signals the appropriate screening context. However, there is no explicit when-to-use guidance or routing versus the sibling scoring tools; the agent must infer selection from the name alone.

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