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

Annotations already establish this is a non-destructive, idempotent write, but the description adds the operationally critical details: the agent must mint its own UUID v4, retrying identical content with the same id is safe and returns the existing note, and mismatched content under a reused id fails with ITEM_IDEMPOTENCY_MISMATCH. It also discloses eventual consistency ('become searchable shortly after'), which no annotation conveys.

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 sentences, each carrying distinct payload: purpose, trigger, id contract, retry/error semantics, and freshness. The idempotency rules are front-loaded after the purpose rather than buried, and no sentence restates the name or annotations.

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 present, return values need not be described, and the description still covers the two things an agent would otherwise fail at: generating the id correctly and interpreting the idempotency-mismatch error. Only the optional title field is unaddressed, a minor gap for a save 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 only 33%, and the description compensates well for the two hardest parameters: it explains the id contract (self-generated UUID v4, reuse on retry) and the content format for authoredContent. The optional hubTitle is never mentioned, so the description leaves one parameter's purpose to inference.

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 ('Save a plain-text or Markdown note into the user's Sensefold library') with the accepted content formats named up front. This clearly separates it from the sibling save_link, which an agent can distinguish 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 user asks to note something down or store text for later') and names the correcting alternative: 'use update_note to change an existing note'. When-to-use and when-to-use-something-else are both present.

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