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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds specific behavioral detail: it 'pulls Meta's actual policy pages', returns quotes verbatim, and 'never changes the creative'. It also mentions the flat 1-credit cost, which is useful operational context beyond the annotations.

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 a single, dense sentence that front-loads the core purpose, then layers specifics about output, behavior, and use cases. No wasted words; every clause adds value. It is appropriately sized for the complexity of the tool.

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 what the tool does, how it behaves (read-only, returns verdicts with quotes), when to use it, and the credit cost. It lacks explicit detail on failure modes or exact response format, but for a read-only check tool with no output schema, it is sufficiently complete for an agent to invoke it 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?

Schema coverage is 100% with each parameter described. The description adds a small nuance for the 'category' parameter (helps pick relevant policy pages) but does not elaborate on copy, claims, or imageDescription beyond the schema. This matches the baseline of 3 for high coverage with minimal extra detail.

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 states a specific verb ('pre-flight'), a resource (ad copy against Meta's Advertising Standards), and the exact output (verdict pass/fix/block with verbatim quotes and rewrites). It clearly distinguishes itself from siblings like plan_ad or render_ad by emphasizing it is a check, not an edit, and by referencing live policy pages.

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 says 'before you run it' and lists specific high-risk categories and claim types where it is especially useful. It implies when to use it (pre-flight) but does not mention alternatives or when not to use it, though no direct sibling offers the same function. Overall, it provides strong contextual guidance.

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