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

Annotations only cover the safety profile (non-read-only, non-destructive, non-idempotent), and the description adds substantial behavior beyond that: minimal default payload, opt-in answer/question text, encryption with the account key, 180-day retention, PII stripping before the check, translation-based checking for non-English answers, and an explicit auth/Pass requirement. This is exactly the context annotations cannot supply.

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?

Front-loaded with the action and the consent condition, then layers retention, encryption, and auth. Dense but mostly earning its place; the language/translation and PII sentences are close in spirit and could be merged, and the description runs long for a single-sentence-per-idea tool.

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 seven parameters, the description covers consent, default vs opt-in persistence, retention, encryption, and auth prerequisites. It does not describe what the call returns (beyond hints that 'the result names this language'), nor duplicate-submission behavior for a non-idempotent write, leaving a small gap.

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 already 100%, so the baseline is 3; the description goes further by explaining that text_en drives the fixed rules for non-English answers, that keep_answer_text governs encryption-at-rest of the text, and that question_id and question_type are alternatives. It stops short of explaining lang's effect beyond what the schema says.

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 (saves one practice answer attempt to the signed-in account) plus the scope of what is persisted by default. It also distinguishes itself from check_interview_answer by noting that the same structure rules apply but that this tool persists progress, so an agent can separate the two without opening either schema.

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?

Gives an explicit trigger — 'when the person asks to save it' — and clarifies the relationship to check_interview_answer. It does not spell out the inverse case (do not call without the person's request) or point at get_practice for retrieval, so the routing guidance is clear but not exhaustive.

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