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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, openWorldHint=true, so 'Read-only' in the description is redundant. The only added context is the single-platform scope, which is mild value; nothing about pagination, result caps, or cross-platform auth is disclosed.

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 short sentences, front-loaded and scannable. The 'Read-only' sentence is redundant against annotations and slightly dilutes the value per sentence, preventing a 5.

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?

Output schema exists and the input schema is fully documented, so the description needn't explain returns or params. However, for a cross-platform listing tool with 5 parameters and an open-world hint, it could note that the platform must already be connected and that results may require paging.

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 100% and the schema already documents platform enum values, ad_set_id requirements for Microsoft Ads, and account_id semantics for DV360. The description adds no parameter meaning beyond the schema, so baseline 3 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?

Clear specific verb+resource ('List ads') and adds scoping ('on one connected ad platform'). Distinguishes itself from siblings like list_campaigns and list_ad_sets by resource name, though it never states that relationship explicitly.

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?

No guidance on when to use this versus list_campaigns/list_ad_sets or how to drill down. An agent must infer that ads are the leaf level of the hierarchy.

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