Check whether cards are due

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered. The description still earns credit by specifying the return type/ordering and by stating a real scheduling rule (learning cards with intervals over 20 minutes are not due until that time elapses), which is behavior an agent cannot get from the annotations or schema.

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 short sentences, no filler. The return contract is front-loaded and the qualifying scheduling rule follows it, so a reader gets the essential fact first.

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 usefully covers the return value and order, which is the main thing an agent needs. It is slightly incomplete on what 'due' means for non-learning card states (review/relearning cards) beyond the 20-minute learning-card rule.

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 100% and the parameter already documents card-vs-note IDs plus its source tools. The description adds only 'same order as input' for the response mapping, so this is the baseline case where the schema does nearly all the work.

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 the exact resource (cards) and the exact question it answers (due for review now), plus the return shape (array of booleans in input order). That is enough to separate it from siblings like are_suspended and get_intervals without opening their schemas, though it never names those siblings 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 can infer this is a pre-review eligibility check and that are_suspended/get_intervals answer different questions. There is no explicit when-to-use or when-not-to-use statement, and no guidance on pairing it with find_cards to obtain IDs.

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