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

Annotations declare destructive/openWorld/non-idempotent, and the description adds context well beyond them: sending now cannot be recalled while a scheduled send can still be changed; and it documents the confirmation handshake (first call returns a question plus confirmToken, second call with same args and token executes). This is exactly the behavioral detail an agent needs for an irreversible open-world mutation.

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?

Front-loaded with the core action and scope, then the confirmation protocol. Dense but each sentence carries information. The confirmation paragraph is a touch long relative to the rest but is warranted by the destructive nature.

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?

For a 6-param destructive tool with no output schema, the description covers preconditions, alternatives, irreversibility, and the confirmation handshake return shape. An agent has everything needed to call it correctly in both confirmation modes.

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%, so the baseline is 3, but the description adds genuine meaning: sendAt must be ISO 8601 with a time zone and in the future; broadcastId comes from draftCampaign; and confirmToken must never be invented. It slightly under-explains sendAsIs and campaignName compared to the schema's own descriptions, so not a full 5.

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 pair (send/schedule) and the resource (a drafted campaign to its audience), and scopes it precisely: 'takes the campaign's broadcastId: draftCampaign gives it.' This distinguishes it clearly from draftCampaign, resendCampaign, updateCampaign and previewSend without opening any 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?

Explicit when-to-use and alternatives: 'Use previewSend first to know who it reaches, and sendTestCampaign to see it in an inbox.' Also states preconditions (only a draft or already-scheduled campaign with subject and content; only a workspace with subscribed email contacts). Nothing is left to inference.

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