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

No annotations are provided, so the description carries the behavioral disclosure burden. It discloses credit costs (2 credits), that empty results and failures are never charged, and cache semantics (free 24-hour hit vs. always-fresh default). It does not cover rate limits or error types, but it transparently covers the most decision-relevant behaviors.

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 three short sentences with no wasted words: the core output and caveat come first, followed by pricing and cache options. Every sentence earns its place and the most critical distinguishing fact (not a speech transcript) is fron-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?

For a simple two-parameter read tool with 100% schema coverage and no output schema, the description is sufficient. It states the output fields, pricing, cache behavior, and non-transcript nature, while the schema handles URL platform constraints. Nothing needed to invoke the tool correctly is missing.

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?

The input schema already fully describes both parameters, including URL/ID format, platform matching, and cache behavior, so schema coverage is 100% and the baseline is 3. The description adds no significant parameter-level detail beyond what the schema provides; it only reinforces cost and cache semantics.

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 exactly what the tool returns — written creative copy from a Meta ad (headline, body, CTA, landing URL) — and explicitly separates it from a speech transcript, which is crucial given the tool's name contains 'transcript'. This scope is unambiguous and distinguishes it from transcript-style siblings like youtube_transcript or tiktok_transcript.

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 provides clear context for when to use it: for Meta ad written copy, not speech audio. It also gives practical invocation guidance such as platform-match requirements and cache behavior. It does not explicitly name an alternative tool like facebook_ad_library_ad_details, but the non-transcript clarification and cost/cache notes give sufficient routing information.

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