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

Annotations already declare destructiveHint=true and idempotentHint=true, and the description corroborates rather than contradicts them by explaining the destruction ("An email already being sent or delivered cannot be recalled") and the idempotency behavior (retrying while pending is a no-op). It adds delivery details absent from annotations — the target is the connected account's verified email address — plus a named failure code, which is real behavioral context beyond the structured fields.

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?

Front-loaded with the action, unit, and range in the first clause, then layered constraints in decreasing priority. Dense but every sentence carries a distinct constraint; slightly crowded with four separate behavioral clauses in a single sentence.

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 4-required-parameter mutation with no output schema and no parameter descriptions, the description supplies the consent gate, delivery target, irreversibility, idempotent-retry semantics, and one error code. The only real gap is what a successful call returns (a schedule identifier or confirmation), which an agent would want before reporting success to a user.

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?

With 0% schema description coverage, the description must carry parameter meaning, and it largely does: it documents the delayHours bounds (1–72), implies channel is email via "check-in email," and frames approved as the explicit-consent gate. It never names the parameters or states that reportId is a UUID, so the mapping relies on inference, but the semantics are recoverable.

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 ("Schedule one installation check-in email") with an explicit window of 1–72 hours, which immediately separates it from siblings like prepare_installation_report or cancel_installation_followup. The scope limit (one check-in per report) further pins down what the tool does.

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 a hard precondition — "only after the user explicitly requests or agrees to that email" — and explicitly disclaims an adjacent use case: "Scheduling authorizes that email, not publication of future feedback." It also defines the retry path (returns the existing schedule) and the terminal-failure path (sent or cancelled returns followup_exists), so an agent knows exactly when to call, retry, or stop.

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