send_bulk_messages_from_list

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

Annotations only indicate not idempotent and not destructive. The description adds crucial behavior: two-step design, token expiration, single-use, and invalidation on argument changes. This goes well beyond the sparse annotations.

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 paragraphs; the first sentence states the purpose, and the second details the necessary two-step process. No fluff, front-loaded.

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's complexity, the description explains the core two-step behavior and token constraints. Output schema exists so return details aren't needed. It doesn't cover mode or context_code behavior, but schema covers those, so it is sufficiently complete for tool selection and invocation.

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 descriptions cover all 7 parameters, so baseline is 3. The description adds semantic context by explaining how confirmation_token is used in the two-step flow and that arguments must be identical, which enriches the schema's simple 'Token from the preview call; omit to preview'.

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 opens with a specific verb+resource: 'Send customized messages to multiple recipients using templates.' This clearly distinguishes it from sibling messaging tools like send_conversation (single conversation) and send_peer_review_reminders (targeted reminders).

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 explains the two-step preview/send flow with clear instructions: call without confirmation_token for preview, then with token and identical arguments to send. However, it does not explicitly compare to alternative sending tools or state when not to use this tool.

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