get_campaign_groups

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so safety is fully covered structurally. The description adds useful domain context that campaign groups organize campaigns and control budget at a higher level, plus that performance data is optional and aggregated, but says nothing about pagination, result limits, or freshness of the performance metrics.

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 core action front-loaded and no filler. The second sentence is explanatory rather than operational, but it is short and earns its place by disambiguating campaign groups.

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?

There is no output schema, so the description bears more burden for return values; it does say the response includes configuration and optionally aggregated performance, which is a reasonable sketch. However, it omits pagination, result limits, and how the date parameters interact with includePerformance, leaving gaps for a five-parameter list tool.

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%, so all five parameters are already documented in the schema and the baseline is 3. The description's mention of optional aggregated performance loosely maps to includePerformance, but adds no syntax, date-format, or default details beyond what the schema provides.

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 ('Lists all campaign groups for an account') and clarifies the returned scope (configuration plus optionally aggregated performance). The second sentence explains what a campaign group is, which helps distinguish it from list_campaigns, though it never names that sibling 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?

There is no when-to-use or when-not-to-use guidance, no mention of alternatives such as list_campaigns or get_campaign_performance, and no indication of when to enable performance or apply the status filter. The phrase 'optionally aggregated performance' hints at a use case but leaves the choice entirely to inference.

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