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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behavior: the tool returns actor, action and timestamp, and results are capped at a 30-day retention window — the latter especially matters since it bounds what the agent can ask for.

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 tight sentences with the resource and return shape front-loaded. The 30-day statement partially repeats the schema's 'Google keeps 30 days' note, which is the only redundancy, but it earns its place as a scoping constraint.

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 zero-required-param read tool with no output schema this covers the essentials: what comes back and how far back it reaches. The notable gap is sibling disambiguation against google_ads_explain_change and other change-related tools, which the agent must resolve on its own.

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 coverage is 75%, with descriptive text on days, folder and account already explaining defaults and the folder-vs-account tradeoff. The description adds no parameter-level meaning beyond the schema, so the baseline 3 applies rather than a penalty.

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 resource and action: 'Recent changes made in the account (who, what, when) from Google Ads change history.' An agent can immediately tell this is a read of the account audit trail. It stops short of 5 because it does not distinguish itself from the close sibling google_ads_explain_change, leaving overlap unresolved.

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?

Usage is only implied — the phrase 'who, what, when' hints at audit/investigation scenarios, but there is no explicit when-to-use, no when-not-to-use, and no named alternative such as google_ads_explain_change for drilling into a single change. The agent must infer the selection rule.

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