Change history

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

Annotations already declare readOnly/openWorld/non-destructive, and the description adds real behavioral context beyond them: the 30-day retention window, the clamping of older start dates to the earliest available day, and the shape of aggregated output (counts by resource type/client/user/day, auto-applied recommendation insights). These are constraints an agent could not infer from the schema.

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?

Purpose and scope are front-loaded in the first sentence, followed by return-shape detail and the retention caveat. The enumeration of clients and the resource URL add some length, but each segment carries useful selection or interpretation value.

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 read-only audit tool with an output schema present, the description covers what is returned, the retention bound, the aggregation summary, and the underlying resource. Nothing an agent needs to invoke it correctly is missing.

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 100%, so the baseline is 3, but the description explains the date_range_start behavior that the schema alone doesn't (older start dates are moved to the earliest available day), which is the one non-obvious parameter interaction. Other parameters are left to the schema.

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 + resource ('List recent account changes: who changed what, when, and through which tool') and grounds it in a concrete API resource (change_event), which clearly separates it from the performance/reporting siblings like get_campaign_performance or run_gaql.

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 a clear use context ('what changed before the drop?') that signals the diagnostic/audit scenario, which no sibling covers. It does not explicitly name an alternative tool or state when not to use it, so it stops short of full routing guidance.

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