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

Annotations already declare idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds a useful scoping signal that only schedule fields are touched, but says nothing about partial-update semantics (do omitted fields reset?) or whether it takes effect on an actively sending campaign.

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?

A single sentence of roughly twenty words, front-loaded with the verb and resource, with no filler or redundancy. Nothing to trim.

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 nine-parameter mutation tool with no output schema and no annotations covering update semantics, the description covers the 'what fields' question but leaves the crucial merge/override behavior and prerequisite state unanswered. Adequate but with a real gap for a write tool of this size.

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 100%, so every parameter (timezone, daysSchedule, startSchedule, endSchedule, everySchedule, sendAt, min/max gap) is already documented with format hints like IANA names and ISO 8601. The description only restates the field groups and adds no format or constraint detail beyond the schema, so 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?

States a specific verb (Updates) plus the exact resource (a campaign's sending schedule) and enumerates the affected facets: timezone, days, time window, frequency. That is enough to separate it from generic update_campaign, though it never names the sibling explicitly.

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?

No when-to-use guidance, no prerequisites (Does the campaign need to be paused? Does it apply to running campaigns?), and no routing to update_campaign for non-schedule fields. The agent must infer usage from the name alone.

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