Validate metric and breakdown combinations before running a Facebook Ads query. Returns errors and warnings to confirm if your query will work.
Validate a metric/breakdown combination BEFORE executing. Returns errors and warnings. Use this to check if your query will work.
| Name | Required | Description | Default |
|---|---|---|---|
| level | No | Aggregation level | |
| metrics | Yes | Metric keys to validate | |
| breakdowns | No | Breakdown keys to validate |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden. It discloses that the tool returns errors and warnings and implies a non-mutating check by saying 'BEFORE executing.' This is adequate, though it does not detail exactly what kinds of validation are performed.
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 short sentences with no filler. The first sentence states the purpose and result, and the second gives a practical usage hint. Every word earns its place and the key action 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?
The description covers the tool's purpose, when to use it, and its return behavior (errors and warnings). The schema fully documents the parameters. It lacks a detailed return schema, but for a validation tool this is a minor gap given the clear description.
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 the schema already documents metrics, breakdowns, and level. The description adds only the phrase 'metric/breakdown combination,' which does not meaningfully extend what the schema already provides; baseline 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 uses a specific verb ('Validate') with a clear resource ('metric/breakdown combination') and adds the temporal qualifier 'BEFORE executing', making its role distinct from querying tools like meta_get_insights. It clearly states the tool's one specific job.
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 gives clear usage context: use this tool before executing a query to check whether it will work. It does not explicitly name alternatives or when-not-to-use scenarios, but the 'before executing' framing effectively signals the intended workflow.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.