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

Annotations only declare the safety profile (non-readonly, non-idempotent, non-destructive), but the description discloses far more: ad status is independent of campaign status, a PAUSED draft serves nothing until enabled, and confirm=false triggers a dry-run. It also explains pinning mechanics and CTR impact of display URL paths, which an agent cannot infer from structured fields.

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?

Front-loaded with the core action, then organized into labeled sections (STATUS, DISPLAY URL PATHS, PINNING) that make it scannable. It is dense and long, but nearly every sentence adds distinct operational value; only the CTR rationale for display URLs is somewhat editorial.

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 13-parameter mutation tool with 0% schema coverage and an output schema present, the description supplies the missing behavioral and parameter context an agent needs to call it correctly. Return values are legitimately omitted given the output schema exists.

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 0%, so the description carries the burden and largely succeeds: it defines status values/default, path1/path2 character limits and semantics, the order-aligned pinning lists, final_mobile_url, tracking_url_template, and confirm. Only customer_id/ad_group_id/final_url are left to implication, which is a minor gap.

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?

Opens with a specific verb and resource ('Adds a Responsive Search Ad (RSA) to an ad group'), which cleanly distinguishes it from siblings like create_microsoft_responsive_search_ad, update_rsa, and create_demand_gen_ad. An agent can identify the operation without opening the schema.

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 explicit conditional guidance ('When you are building a campaign for review, pass status=ENABLED') and routes follow-up changes to update_ad_status. It stops short of contrasting against sibling ad-creation tools (e.g. why this vs. a demand-gen ad), so it is clear context rather than full when/when-not routing.

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