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

Annotations already declare readOnly=false, openWorld=true, idempotent=false, and destructive=false, but the description adds critical hidden behavior: image_url is fetched/uploaded automatically, an image is required despite the schema marking it optional, creating submits the creative for review, the ad is created paused unless activate=true, and confirm=false returns a dry run. This is exactly the extra context an agent needs to invoke the tool safely.

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-loaded with the core purpose, then moves through concise operational details with no redundant sentences. The length is appropriate for a creation tool with several hidden rules and a dry-run mode.

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?

An output schema exists, so return values need not be described, and annotations already cover the safety profile. However, with 0% schema coverage across 9 parameters, missing explanations for name and account and no explicit sibling routing leave minor gaps for an agent.

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?

With 0% schema description coverage across 9 parameters, the description must compensate and mostly does. It clarifies title, body, target_url, image_url, confirm, and activate semantics, but name and account remain unexplained. The important creative and control parameters are covered, though two parameters lack any definition.

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 (creates) and resource (ChatGPT Ads ad / chat card) scoped inside an ad group. Distinguishes clearly from create_chatgpt_ads_ad_group and create_chatgpt_ads_campaign, and from other platform-specific ad creation tools, by naming ChatGPT Ads ad.

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?

Provides useful operational context: requires an ad group, image is required for a chat card, and creative should be final before submission. However, it does not explicitly say when to use this versus update_chatgpt_ads_ad, chatgpt_ads_ad_preview, or other ad creation tools. The dry-run behavior is noted but not framed as an alternative workflow.

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