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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety needs no restating. The description adds real behavioral context beyond them: the async readiness lifecycle (ads become ready after make_ads, campaign becomes paused after send_ads_to_platform), which tells the agent this is a polling endpoint with eventually-consistent state.

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?

Two sentences, zero filler. The return contents are front-loaded and the polling instructions follow immediately, so an agent gets purpose and timing in the first read.

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 the description need not explain return shape, and the polling guidance covers the main operational unknown. It is nearly complete for a simple single-resource getter, though it could have noted the campaign_id failure mode or that a non-ready campaign still returns partial ad data.

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?

There is a single required campaign_id and schema coverage is 100%, with the schema itself stating it comes from list_ad_campaigns or make_ads. The description adds nothing about the parameter, so the baseline 3 for a fully documented single parameter applies.

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 opening phrase "One ad campaign:" plus the enumeration of what is returned (plan, Page, each ad with creative asset_url, shape, copy, status) makes the resource and scope unambiguous, and the singular framing implicitly separates it from list_ad_campaigns. It never states a verb like 'retrieve' and never names list_ad_campaigns as the sibling it differs from, so it stops short of a 5.

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 concrete usage conditions with named siblings: poll after make_ads until every ad is ready, and after send_ads_to_platform until it is paused. That is strong 'when to use' guidance tied to specific tool transitions. It offers no exclusions (e.g. use list_ad_campaigns to enumerate campaigns), which keeps it at 4 rather than 5.

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