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

Annotations declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful non-schema behavior: default PAUSED state, that text limits are validated before any call is sent, and that dryRun is free and cannot affect spend. It stops short of describing what the call returns, but there is no output schema to explain either.

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?

Four sentences, front-loaded with the creation mechanic, then default state, then dryRun guidance. The closing editorial instruction about honest ad copy is arguably extra but is short and actionable rather than filler.

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 9-parameter creation tool with no output schema, the description covers the essential behavioral facts an agent needs: default paused status, pre-send validation, and a dryRun escape hatch. Only the return value and the pointer to the update sibling are missing, which is a minor gap given the rich schema.

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%, with per-parameter descriptions covering ranges, character limits, enums, and dependencies (path2 needs path1). The description adds little parameter-level detail beyond the headline/description mixing concept, so the schema carries the load and a baseline 3 is appropriate.

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 and resource ('Create a responsive search ad in an ad group') and explains the core mechanic of headlines/descriptions being mixed and matched. This clearly distinguishes it from msads_update_responsive_search_ad and the Google-flavored create_responsive_search_ad sibling.

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 clear operational context: use dryRun to review the ad first, and note that ads are created PAUSED so they won't serve until activated. It doesn't explicitly enumerate when to prefer this over update_responsive_search_ad, but the create-vs-update split is implied by the verb.

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