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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed world), and the description adds genuinely new behavior: the derived definition of 'open', that answered questions silently drop out once a follow-up exists, the newest-first ordering, and the hard 50-item ceiling. The truncation cap is exactly the kind of hidden constraint an agent needs before treating results as exhaustive.

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?

Three sentences, each earning its place: definition and ordering first, the follow-up/answered rule second, scoping third, with the negative guidance last. No restatement of the name or title and no filler.

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?

An output schema exists, so return shape need not be explained; what remains — what counts as open, ordering, scoping, and the result cap — is all covered. Nothing an agent needs in order to call this correctly or interpret its output 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 real meaning beyond the schema by explaining that a collection_id can address a subject which itself includes the collections within it, and by restating the 50-question ceiling that bounds the limit parameter. The limit parameter's default/tuning behavior is left entirely to 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 specific verb and resource plus the exact operational definition of 'open' (a note whose text ends in a question mark with no follow-up note continuing it) and the sort order (newest first). This is precise enough to distinguish it from siblings like search_notes or get_note without opening a 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 clear when-to-use context ('Pass collection_id to get the open questions in one book, article, podcast or subject') and an explicit when-not ('Not for counting: it returns at most 50 questions'). The only gap is that the counting alternative is described by behavior rather than named, so the agent must map that to count_notes itself.

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