create_campaign_assignment

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

With no annotations, the description carries the full burden of behavioral disclosure, but it only states that a new assignment is created. It does not mention side effects, required campaign/advertisement state, authorization needs, whether the operation is reversible, or what the response contains.

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?

The description is a single concise sentence with a clarifying parenthetical. Every word contributes to understanding the tool's purpose, and there is no redundant or fluff content.

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?

This is a create operation with 11 parameters, nested objects, conditional dependencies (e.g., schedule only if campaign scheduling_source is AD_ITEM), and no output schema or annotations. The one-sentence description does not provide enough context for correct invocation, edge cases, or expected behavior.

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 the schema already documents each of the 11 parameters thoroughly. The description adds only minimal relational context ('assign an ad item to a campaign'), which slightly reinforces the required parameters but does not add meaning beyond the schema.

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?

The description uses a specific verb ('Create') and resource ('campaign assignment') and clarifies the action with the parenthetical 'assign an ad item to a campaign,' which defines the core relationship. However, it does not differentiate this tool from sibling tools like draft_create_campaign_assignment, vast_create_campaign_assignment, or vast42_create_campaign_assignment.

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 guidance is provided about when to use this tool versus alternatives such as draft_create_campaign_assignment or the vast/vast42 variants. There are no exclusions, prerequisites, or context cues to help an agent choose among the many similar create/update/list/delete siblings.

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