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

Goes well beyond the annotations by disclosing that sequence/accounts/tagIds replace wholesale, that steps and variants receive new ids, and that a running campaign's sequence update is rejected atomically. However, several of these replacement semantics are already documented in the schema field descriptions, so the marginal value is real but partly duplicated.

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-loads the core rule — only passed sections change — then layers the replacement caveats in order of risk. It is dense and readable, though the long compound sentences demand careful parsing.

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 destructive partial-update tool with a deeply nested schema and no output schema, it covers the highest-risk behaviors: replacement, id churn, and rejection when a campaign is running. Permissions or auth requirements are not mentioned, which leaves a small gap.

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 86%, so the schema already documents parameters thoroughly, including REPLACES semantics on tagIds, accounts and sequence. The description reinforces the variant/step shape but adds little that the nested field descriptions do not already say.

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?

"Change a campaign" states a specific verb and resource, and the surrounding sentences make clear this is a partial-update tool rather than a creation or deletion one. It never names create_campaign or get_campaign as the alternatives explicitly, so sibling 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?

Gives concrete when-to-use context: pass only the sections you want changed, pause a running campaign before replacing its sequence, and re-read get_campaign before send_test_email. It lacks explicit when-not-to-use guidance (e.g. versus update_subsequence or create_campaign), which keeps it below a 5.

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