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

Adds genuinely useful context beyond the annotations by disclosing the required manage_campaigns scope, which annotations do not carry. However, it says nothing about what stopping does to an in-flight send, whether the action is reversible, or what the 'manual' reason implies downstream — notable gaps for a mutation tool whose destructiveHint is false.

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 short sentences, front-loaded with the action and scope, with zero filler. The parenthetical '(reason manual)' is terse to the point of ambiguity, which slightly undercuts the otherwise tight phrasing.

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?

Adequate for a simple two-required-parameter mutation: annotations cover safety and idempotency, the schema covers all parameters, and the description covers the auth scope. It still leaves the agent guessing about side effects on an active send and whether the stop can be undone.

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% and the idempotency_key parameter is fully documented in the schema, so the description has little left to add. It contributes no meaning about campaign_id or enrollment_id beyond what the schema already states.

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 ('Stop') and a precise, scoped resource ('a single enrollment'), which contrasts with the campaign-level siblings pause_campaign/resume_campaign. It does not name those siblings explicitly, so the differentiation is implied rather than stated.

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?

There is no guidance on when to stop an enrollment versus pausing/resuming a campaign or adding a suppression, and no stated exclusions. The only usage information is the prerequisite scope, which tells the agent it can call the tool but not when it should.

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