get_campaign_performance

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

With no annotations provided, the description carries the full burden. 'Retrieves' and 'Returns' signal a read-only reporting operation with no side effects, and the description openly states the date-range scope and the kinds of metrics returned. It does not disclose potential quirks like pagination or data aggregation behavior, but for a read-only metrics tool the core behavior is well conveyed.

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?

The description is two tight sentences: the first states the operation, the second lists return metrics and the primary use case. Every sentence earns its place, and the key information is front-loaded.

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?

Given that there is no output schema, listing the returned metrics is helpful for an agent to interpret results. The 6-parameter input schema is fully described, and the description covers the tool's core output and purpose. A fully complete description might also note return grouping or default date behavior, but the definition is adequate for correct invocation.

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?

Input schema coverage is 100%, so the parameters are already well-documented. The description adds general context about date ranges and metric types, but it does not add meaning beyond what the schema provides for individual parameters, such as campaignIds or timeGranularity.

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?

The description clearly states a specific action and resource: 'Retrieves performance metrics for campaigns within a specified date range.' It also lists the key metrics returned, making the tool's function concrete. However, it does not explicitly contrast itself with closely related siblings like get_creative_performance or get_conversion_performance, so it falls just short of full differentiation.

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?

The phrase 'The primary tool for daily campaign monitoring and optimization decisions' gives a clear context for when to choose it, indicating a routine monitoring scenario. It does not mention exclusions or explicitly name alternatives, so it provides context but not a full when-to-use vs. when-not-to-use comparison.

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