meta_ads_analysis_placements

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

The description explicitly states 'Read-only' and details the output format, which is the key behavioral trait. With no annotations provided, this disclosure carries full weight. It could have also mentioned quota costs, but the schema's period description covers that. Overall it's transparent for a read-only analysis tool.

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?

Four sentences, all in service of the purpose. It front-loads the verb and resource, then provides output details, read-only note, use case, and alternative. No waste, well-structured.

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 there is no output schema, the description compensates by fully describing the return value ('rows per placement with spend, conversions, CPA, ctr, and a recommendation'). It also covers usage, read-only, and the alternative tool. The description is complete for this tool's complexity.

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 explains all parameters. The description adds context by mentioning 'campaign' in the usage scenario, but it does not add significant parameter semantics beyond what's in the schema. 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 clearly states the tool 'Scores delivery efficiency across Meta placements' and lists the specific output (rows per placement with metrics, recommendation). It distinguishes itself from the raw-data sibling by explicitly naming meta_ads_insights_breakdown as an alternative for raw numbers.

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?

Provides explicit usage guidance: 'Call this when CPA drifts on a campaign' and names the exact alternative for raw numbers ('use meta_ads_insights_breakdown with breakdown="placement"'). This clearly tells when to use this tool vs another.

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