Get Delivery Estimate

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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds return value information (estimated daily outcomes and bid suggestion) but does not disclose potential edge cases, rate limits, or how estimates might vary.

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 concise and well-structured, with a clear first sentence followed by labeled Args and Returns sections. Every line adds useful information without unnecessary elaboration.

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 read-only tool, the description covers the purpose, key parameter, and return values. Annotations handle safety. It could be more complete by clarifying how this differs from meta_get_reach_estimate, but it is sufficient for correct invocation.

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 description labels adset_id as 'Ad set ID,' which adds little beyond the parameter name and does not explain where to obtain the ID or its format. The response_format parameter is already well-described in the schema, so the description contributes minimal semantic value.

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 states 'Gets delivery estimate for an existing ad set,' identifying a specific verb and resource. It is distinct from a generic reach estimate, though it does not explicitly differentiate from the similar sibling meta_get_reach_estimate.

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 phrase 'for an existing ad set' provides a clear usage context, indicating the tool applies to existing ad sets rather than prospective targeting. However, it does not explicitly mention alternatives or when not to use the tool.

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