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

Adds genuinely non-obvious context beyond the annotations: the 'today' boundary is computed in the user's own timezone, and results are paged via next_cursor. Annotations already cover the safety profile (readOnly=true, destructive=false), so this supplemental behavioral detail earns credit. It doesn't explain ordering or why two calls may return different sets despite being a read.

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 front-loaded sentence with the core predicate first and the pagination hint parenthetical. Nothing is wasted.

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 an output schema and full schema coverage, the description only needs to frame the resource and pagination, which it does. It leaves unstated whether the result set is stable within a day or how it is ordered, a minor gap for a review-queue tool.

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 all three parameters are fully documented in the schema, making 3 the baseline. The description reinforces the cursor mechanism and the timezone framing but says nothing about limit or notebook_id scoping that the schema doesn't already cover.

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 resource and predicate: the words due for review today, paginated. It is clearly distinguishable from get_recent_words, list_words, and get_word. It does not explicitly name a sibling alternative, which keeps it from a 5.

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?

Use is implied by 'due for review today' — the description signals the review-queue scenario without naming when to prefer get_recent_words or list_words instead. No prerequisites or exclusions are stated.

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