meta_ads_analysis_performance

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

No annotations are provided, so the description carries the full burden. It explicitly states 'Read-only', a key behavioral trait, and describes the output in detail (current/prior metrics, delta %, ranked callouts). It does not mention rate limits or authentication needs but adequately covers safety and functionality.

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 concise: two main sentences plus a terse 'Read-only' statement. It front-loads the primary purpose, lists return components, and provides usage guidance without unnecessary words. Every sentence adds 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?

The tool has moderate complexity (performance review with comparison), no output schema, and 100% parameter coverage. The description explains the output (metrics, delta %, callouts) with examples, and gives usage context. While it could specify which metrics are included, it is sufficiently complete for an agent to understand and invoke the tool correctly.

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?

All three parameters have complete descriptions in the input schema (100% coverage). The tool description adds context about the output behavior (period-over-period comparison) but does not provide additional parameter-level details beyond repeating the schema. According to guidelines, with high schema coverage, a baseline of 3 is appropriate.

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 that the tool produces an operator-ready performance review with period-over-period comparison, specifying the resource (campaign or account) and outputs (metrics, delta %, callouts). It distinguishes itself from the sibling meta_ads_insights_report by noting it narrows attention before pulling raw insights.

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 explicitly advises using this tool at the start of an audit to narrow focus before using meta_ads_insights_report, providing clear context and an alternative. While it does not exhaustively list all alternatives, the guidance is practical and specific.

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