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

With no annotations, the description carries the full burden. It does disclose that the tool creates a campaign and returns media_buy_id, campaign_id, creative_deadline, targeting_summary, and budget_summary. However, it omits important behavioral details such as whether this commits spend, executes the buy immediately, is asynchronous, or has idempotency implications.

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 well-structured with a summary, WHEN TO USE, RETURNS, and a concrete example. It is somewhat long but each section adds value and the most important information is front-loaded.

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 complex 11-parameter nested tool with no output schema and no annotations, the description gives a helpful example and return summary, but still leaves gaps around required versus optional fields, package-based vs legacy buy_spec usage, and execution/confirmation 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 64%, so the schema documents many parameters. The example adds meaningful structure for buy_spec, creative, geo, budget, schedule, and buyer_ref, but the description does not clarify packages, total_budget, start_time/end_time, idempotency_key, or how the legacy buy_spec relates to the newer package-based fields.

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 clearly identifies a specific verb and resource: create a media buy (campaign) from an AdCP buy specification, targeting DOOH screens. It is specific about what the tool does, though it does not explicitly distinguish itself from the sibling create_campaign beyond the AdCP/DOOH context.

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?

The WHEN TO USE section gives clear contexts: AI-agent-driven programmatic DOOH buys, DSP trading desk agents, and automated media buying workflows. It does not explicitly state when not to use it or compare against alternatives like create_campaign or update_media_buy, but the provided guidance is concrete and useful.

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