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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered. The description adds real context beyond that: it enumerates what is returned (updated_at for approved settings changes, workflow, sender assignments, schedule, review mode, action state, readiness blockers) and clarifies two non-obvious behaviors – empty templates are not claimed as generated, and no sending or activation occurs.

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?

Three dense sentences, front-loaded with the core action, then return content, then behavioral caveats. Every sentence carries information; the middle enumeration is long but purposeful given no output schema exists.

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?

With no output schema, the description correctly takes on responsibility for describing the return payload and the absence of side effects. Combined with full annotation coverage and a fully documented single parameter, an agent has nearly everything needed; only explicit routing versus list_campaigns is missing.

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 campaign_id is fully documented with UUID format and example, so the schema carries this dimension. The description adds only 'in the selected product' as ambient scope context and nothing about the identifier itself; baseline 3 is appropriate.

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+resource ('Read one campaign') with clear singular scope that implicitly separates it from list_campaigns. It does not explicitly name the sibling it contrasts with, so it stops short of a 5.

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 by 'Read one campaign in the selected product' – fetch a single campaign by id rather than enumerating. There is no explicit when-to-use guidance, no exclusions, and no mention of list_campaigns or the update/enable/pause siblings as alternatives.

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