Create ad

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

Annotations already cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true), so the bar is lower. The description adds real value beyond them: the default PAUSED status and the dependency on a pre-existing post. It does not mention authorization requirements or what the response returns, but for a create tool with no output schema that is a minor gap.

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, front-loaded with the action, then prerequisite, then default status. Every sentence carries actionable information; nothing is redundant with 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 create-only tool with no output schema, the description covers the prerequisite, the id format, and the default status. It does not note the required ad_group_id/name/configured_status explicitly, though those are already in the 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 coverage is 100% and the nested data object is thoroughly documented, so baseline is 3. The description still adds the t3_... post_id format and where that id comes from, tying the parameter to the prerequisite tool rather than leaving it as a bare string.

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 precise verb+resource+scope: 'Create an ad in an ad group.' This clearly separates it from reddit_ads_create_campaign and reddit_ads_create_ad_group, and it further distinguishes the standard-ad path from the Reddit Max flow.

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 the explicit prerequisite chain — create the post first with reddit_ads_create_post_job (or reddit_ads_create_post) and pass its post_id — and states the default operational behavior ('Create it PAUSED unless the user asks otherwise'). The agent knows both how to prepare and how to invoke.

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