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

Annotations already cover safety profile (idempotent, non-destructive); the description adds one useful behavioral detail: changing the schedule reschedules the next run. This goes beyond the schema and annotations but could still mention how updates interact with currently executing campaigns.

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 operative verb and resource, then a single behavioral side-effect. No redundant wording.

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 10-parameter update tool with nested schedule/messageSource objects, the description is under-specified. It does not address effects on a running campaign, pacing behavior, or any prerequisites, leaving the agent to infer much from the schema. Not fully usable without additional context.

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?

With only ~30% schema description coverage, the description provides a high-level grouping of updateable fields but omits botId and loopCooldownMs. It does not explain semantics of 'send settings' or exhaust behavior, though enums in the schema cover some of this. Partially compensates for low coverage.

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?

Specific verb 'Update' plus resource 'paced list campaign' and a list of mutable fields (name, message source, batch size, schedule, exhaust behavior, send settings). The resource is clearly distinct from sibling update_campaign, though the description does not explicitly call out any alternative tools.

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?

Usage is implied: to modify a paced list campaign, use this tool. There is no explicit when-to-use vs the create/pause/resume/run-now siblings, and no caveats about when updates are allowed (e.g., paused vs running campaigns).

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