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

Adds non-obvious side-effect semantics well beyond the annotations: pausing cancels pending actions, resuming recreates only interrupted active steps, previously excluded contacts stay excluded, and only supplied fields are changed (patch, not replace). This usefully clarifies what destructiveHint=false and idempotentHint=true actually mean for the status transitions.

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 purpose and the field list, then layered with the status semantics and the partial-update rule. No filler sentences; every clause carries actionable information.

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 7-parameter mutation tool with no output schema and only safety-oriented annotations, the description covers mutation semantics and the riskiest enum values well. It leaves unaddressed what draft/stopped do and whether any confirmation or return payload is produced.

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; the description goes beyond it by explaining the status enum's behavioral meaning for paused/running and the partial-update contract for omitted fields. It does not explain the draft or stopped enum values, which remain schema-only.

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?

Names a specific verb (Update) and resource (settings of an existing campaign) and enumerates the mutable fields (name, description, daily_limit, sender_context, auto_approve_messages, status). It also scopes ownership ("a campaign you own"), so an agent can distinguish it from create_campaign or the list/get tools without opening the 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?

Gives clear value-dependent context: status='paused' cancels pending actions safely, while status='running' is a real resume that routes through start_campaign. It stops short of explicitly declaring when to prefer a sibling (e.g. stop_campaign vs status='stopped'), leaving a small inference gap.

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