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

Annotations already cover the safety profile (read-only, idempotent, non-destructive), and the description adds real behavioral context beyond them: the result may be null until sufficient history exists, and a readiness signal reports how much history is available. The Intelligence-plan dependency is a genuine prerequisite not visible in the schema.

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 dense sentences, front-loaded with the purpose and null/readiness behavior, with no filler. The phrasing is slightly clipped but every clause carries information.

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 no output schema, the description compensates by naming the returned concepts (timing, readiness) and their null semantics, plus the prerequisite. An agent can call it correctly; only the concrete shape of the response 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 description coverage is 100% and the single parameter productId is already documented, including the all-brands vs single-brand distinction. The description adds nothing about this parameter, 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?

The description names a specific output ('When this brand's audience responds best') and its data source (Markaestro Intelligence, brand's own post history, not an industry table), which cleanly separates it from the generic analytics and listing siblings. It stops short of naming a specific alternative tool the agent might otherwise reach for.

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?

It states the action it feeds ('Use it to pick scheduledAt') and a hard prerequisite ('Needs a plan with Intelligence'), which is exactly the routing information an agent needs. No explicit when-not or named alternative is given, so it is not a full 5.

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