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

Adds substantial context beyond the annotations: preserved fields, the queue-slot side effect, the exact return shape { status, scheduledAt }, three distinct refusal conditions, required `publish` scope or admin, Pro-plan gating, and a monthly quota cost. That is the quota/permission/refusal detail annotations can't express, and nothing contradicts destructiveHint or idempotentHint.

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?

The action is front-loaded after the scope tag, and every clause carries distinct information (format, invariants, return, refusals, prerequisites, PATCH mapping). It is dense near the limit of readability but has no filler sentences.

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?

A mutation tool with no output schema, yet the description covers the return value, authorization, plan requirement, quota impact, failure modes, and where the `id` comes from. Nothing an agent needs to call it correctly is left implicit.

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% and the schema already carries the ISO 8601 example, the "more than 5 minutes in the future" constraint, and the "send it on its own" rule. The description mostly repeats that, adding only the clarification that the timezone must be explicit, so the baseline 3 applies.

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 ("MOVES A SCHEDULED POST to `scheduledAt`") and, crucially, what is preserved versus changed — "keeps its id, caption, media, accounts and options; its posting-queue slot follows" — which is exactly what separates it from update_scheduled_post and cancel_scheduled_post. An agent can pick it without opening the 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 explicit when-not conditions (refused within 5 minutes of the slot, while posting or posted, and in review-required brands) plus an operating instruction to confirm the time and timezone with the user first. It does not name a sibling alternative for the "change the caption instead" case, relying on the preserved-fields sentence to imply it, which keeps this short of a 5.

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