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

Goes well beyond annotations by disclosing atomicity, server-side timestamping, the reduced return shape (no card text or editable memory state), and precise 409 semantics for REVIEW_EVENT_CONFLICT and REVIEW_ID_CARD_MISMATCH, including that no duplicate or write occurs. This is exactly the retry/conflict context the idempotentHint and destructiveHint flags cannot convey.

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?

Four tight sentences, front-loaded with the core action, then constraints, then error behavior. No filler; every clause carries operational information.

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 mutation tool with a rich parameter set and an output schema, the description supplies what structured fields cannot: atomicity, conflict/retry handling, and what is deliberately omitted from the response. Nothing an agent needs to call it safely is missing.

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%, so the baseline is 3, but the description adds meaning the schema does not: reuse of reviewId on retries is tied to the 409 conflict behavior, and reviewedTimeZone's purpose (authoritative schedule vs. local streak day) is clarified. Per-field semantics remain mostly in the schema.

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 precise verb+resource ('atomically records the supplied review rating and advances the card's authoritative FSRS schedule'), and the scope is immediately distinguishable from read-only siblings like next_review_card or reveal_answer. An agent knows this is the write step of the review loop.

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?

It draws a clear boundary with 'Server stamps online review time; no history import', telling the agent this is only for live reviews, not backfilling. It does not explicitly name sibling alternatives, but the exclusions give actionable context.

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