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

Annotations already declare readOnlyHint=true, openWorldHint=false, and destructiveHint=false, so safety is covered structurally. The description adds real behavioral context beyond that: a hard access gate tied to business tier, a mandatory pre-check call, and required surfacing of grace-period warnings and a verified resubscribe link before continuing.

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?

Purpose is front-loaded in the first sentence, which is good. However, the remaining three sentences are access-gating boilerplate with redundancy: 'check business permissions' before requesting inputs and 'Call check_business_tool_access before collecting inputs' restate the same rule twice, consuming most of the description's length.

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 read-only two-parameter getter with full schema coverage and no output schema, the main risks are access-tier misuse and invalid IDs, and the description addresses both (via the permission gate and the schema's ID sourcing note). It does not describe what the returned campaign contains, which is acceptable given there is no output schema.

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% and both campaignId and communityId are documented in the schema, including the 'never invent one' warning for communityId. The description adds only that the campaign belongs to a 'managed community,' which does not extend per-parameter meaning 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?

Opens with a specific verb and resource: 'Get one Magic Audience / Magic Ads campaign for a managed community,' which contrasts implicitly with the plural list_magic_audience_campaigns sibling. It is clear and singular-scoped, though it never names an alternative tool to differentiate from directly.

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 explicit preconditions: check business permissions first, FREE businesses are blocked regardless of feature rows, call check_business_tool_access before collecting inputs, and never proceed when access is blocked. It does not address when to prefer this over the sibling estimate/create/update tools, but the gating guidance is unusually concrete.

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