Create Do Not Reach list

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

Annotations show this is a write operation, and the description adds useful behavioral details: the DNR list is a suppression list, each account can only have one, and the API assigns the name 'Do Not Reach List'. It does not address failure behavior for an existing list, but the one-per-account note covers the main risk.

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 short sentences, each earning its place: the creation action, the one-per-account/naming constraints, and the required follow-up tool. No filler or repetition of the schema.

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 simple two-parameter creation call, the description covers the resource, cardinality, naming, optional field, and next workflow step. It does not describe the return value or error when a DNR list already exists, but those are minor given the one-per-account warning.

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?

The schema already documents account_id with a source hint and example, and the description adds only that a description is optional and is the only optional field. This is useful but does not fully compensate for the undocumented description parameter's format/length semantics.

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 action ('Create') and resource ('account DNR (suppression) list'), with constraints: 'One per account' and the API name 'Do Not Reach List'. This clearly distinguishes it from sibling create_* tools such as x_ads_create_audience or x_ads_create_pixel.

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 clear context by noting the one-per-account constraint and the follow-up step 'Then load emails with x_ads_dnr_users', so an agent knows when creation applies and what comes next. It does not explicitly contrast with x_ads_list_dnr/x_ads_delete_dnr, so it misses a full when-not/alternatives statement.

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