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

Annotations already declare readOnly=false, destructive=false, idempotent=false and openWorld=false. The description adds the useful fact that the result is an unsent draft with no recipients. It does not warn that retries create duplicate drafts despite idempotentHint=false, nor mention any domain/verification requirement for from_email.

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?

Two sentences, front-loaded with the action and then the sequencers. Every clause carries routing information; nothing is wasted.

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 16-parameter creation tool with no output schema, the description is adequate on workflow but silent on what comes back (presumably a campaign id needed for update-campaign) and on the draft's default settings. An agent can act, but with avoidable guesswork.

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 69%, a mid-range case where the schema documents the nontrivial fields (ab_test, utm_params, tracking overrides) while the plain fields are self-explanatory. The description adds no parameter meaning at all, so it neither compensates for the gap nor detracts; 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?

"Create a draft campaign" gives a specific verb plus the key state qualifier (draft, not sent), which meaningfully separates it from send-campaign and the other create-* tools. It does not explicitly contrast with adjacent creation tools like create-template, but the resource is unambiguous.

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 spells out the workflow: add recipients via update-campaign, then send via send-campaign. That tells an agent the campaign is empty on creation and which sibling to call next. It stops short of stating when a campaign is the wrong choice (e.g. vs. automation) or any prerequisites.

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