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

Annotations only indicate readOnlyHint=false (a write operation), so the description carries the burden of disclosing behavioral traits. It explicitly states the broadcast is NOT sent and requires admin review, which is key behavioral context beyond the annotations. It doesn't mention other side effects like idempotency, but the draft nature is well disclosed.

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 description is two concise sentences, front-loaded with the core purpose and then the critical caveat. Every word earns its place; there is no redundant or filler content.

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?

Given the tool has an output schema, return values don't need explanation. The description covers the essential context: it creates a draft, not sent, admin review required. It could add a note about how scheduledAt behaves with drafts (e.g., scheduled after approval), but the current description is complete enough for most use cases.

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%, so parameters are already well-documented (e.g., channel enum, scheduledAt ISO date, recipientFilter object). The description adds only the draft-related context that affects how the created broadcast behaves, but it doesn't provide additional parameter-level details beyond the schema. Baseline 3 is appropriate.

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 uses a specific verb and resource: 'Create a DRAFT WhatsApp or SMS broadcast campaign.' It clearly distinguishes this from other create_* tools by emphasizing the draft status and the need for admin review, avoiding confusion with create_campaign or other send-related tools.

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 clearly implies when to use this tool: when you need to create a broadcast that won't go out immediately but requires admin approval. It doesn't explicitly name alternatives, but the context of the broadcast not being sent and the existence of validate_campaign and request_send_approval siblings gives enough context. No explicit exclusions are provided, so it falls 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.