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

Annotations already declare readOnly=true, destructive=false, openWorld=true, so the safety profile is covered. The description earns credit for adding non-obvious operational context: the tool never sends messages, requires server-side provider configuration, is free and unauthenticated, and is rate limited — auth and rate-limit details are exactly what annotations cannot convey.

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?

Five short, front-loaded sentences with no filler; the most decision-relevant constraint (drafts only, never sends) appears immediately. 'Provider configuration required server-side' is slightly cryptic but still earns its place.

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 values need no explanation, and the description covers safety, auth, cost, rate limits, and the non-sending guarantee. The one meaningful gap is that no parameter semantics are conveyed despite 0% schema coverage.

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 0% and the description mentions no parameters at all — nothing about useCase, businessBio, businessName, messageTone, or addEmoji. With five undocumented parameters and no schema descriptions, the description fails to compensate for the coverage gap.

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 ('Generate'), resource ('business WhatsApp message draft'), and names the underlying provider. The 'Only drafts text; never sends messages' clause pins down exactly what the tool does and does not produce, making it unmistakable against the unrelated sibling set.

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?

The description gives strong scope boundaries (draft only, never sends) and operating conditions (free, no auth, rate limited), but never states when to reach for this tool versus an alternative or what a caller must supply to get a good result. Usage is implied by the drafting scope rather than explicitly guided.

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