Draft attaching a brand list

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

Annotations only give the generic write/non-destructive/open-world profile; the description adds substantial context beyond that: it creates a CampaignCriterion.brand_list per campaign, returns a preview with a plan_id, and nothing mutates until confirm_and_apply is called. That two-phase draft/apply behavior is essential and not derivable from annotations.

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 action and the PREVIEW nature of the result, then layers the sibling distinction and prerequisite flow. Each sentence carries a distinct piece of information; the API doc link is the only disposable element and is minimal.

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?

Given four params, a full schema, an output schema, and a preview/apply workflow, the description supplies everything an agent needs: input provenance, mutation semantics, downstream confirmation step, and the criterion-vs-shared-set distinction. Nothing material 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 coverage is 100%, so the baseline is 3, but the description adds meaning by explaining that `negative` decides the role (criteria vs. exclusion) and that shared_set_id originates from get_brand_lists. It stops short of documenting customer_id behavior, but the schema already covers the parameters.

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 (attach an existing brand list to campaigns) and immediately distinguishes it from the nearest sibling by declaring it is NOT the CampaignSharedSet linkage used for negative keyword lists. An agent can tell it apart from attach_shared_set_to_campaigns without opening either schema.

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?

Explicitly routes the agent: shared_set_id comes from get_brand_lists, get_brand_list_campaigns lists existing attachments, and the result must be applied via confirm_and_apply. It also clarifies the negative-vs-exclusion semantic split, leaving no inference needed about when to use this vs. the shared-set tool.

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