Spend & Performance Forecast

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true. Description adds that it uses moving-average extrapolation over last 14 days, returning confidence_level and warnings when data is volatile or campaigns paused. This goes beyond annotations with useful behavioral context.

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 sentences with a clear input/output breakdown and additional context for confidence. Every sentence adds value, and the structure is front-loaded with purpose.

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 two optional parameters, annotations, and no output schema, the description covers purpose, inputs, behavior, and output shape (projected metrics and confidence). It lacks explanation of what happens if no platform is provided (e.g., aggregates all platforms), but this is minor.

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 has 50% description coverage; period_days has description 'Forecast period' and enum, platform has enum only. Description adds that period_days can be '7'|'14'|'30' and that platform is optional, while also explaining the overall usage. This partially compensates for the missing platform description.

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?

Description clearly states the tool projects future ad spend and performance from historical trends. It specifies inputs (period_days, platform) and outputs (spend, impressions, etc.), distinguishing it from siblings like budget_analyze or anomaly_detect.

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 description explains when to use (for forecasting based on recent data) and provides context via confidence_level and warnings, but does not explicitly state when not to use or name alternatives, though siblings like budget_analyze exist.

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