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

With no annotations provided, the description carries the full behavioral disclosure burden and does so well for billing and caching: it states the 4-credit cost, that empty results and failures are free, and that cache=true yields a free 24-hour hit with a default of always fresh. This meaningfully informs the agent about side effects and costs, though it omits rate limits, auth, or response-shape behavior.

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 very short and contains no wasted words; the two sentences deliver the cost and cache facts efficiently. The awkward opening 'Summarizer' is a structural weakness, but overall conciseness is strong.

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 no annotations and no output schema, so the description needs to specify what the tool does, what it returns, and when to select it. It does none of those things. The schema documents the parameters well, but the core purpose and selection context are missing, leaving an agent to rely on the tool name.

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 has 100% parameter coverage with detailed descriptions for both url and cache, including the cross-platform URL restriction and cache semantics. The description adds little beyond repeating the freshness default and attaching a cost implication to cache hits, so schema carries the load and the description is adequate but not additive.

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 opens with 'Summarizer' but never states what is summarized — no mention of Facebook, videos, posts, or any other resource. This is effectively a tautology of the tool name 'facebook_summarize'; the actual purpose must be inferred from the name and input schema rather than the description.

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 operational guidance about caching and cost, but it does not say when to use this tool versus sibling alternatives like facebook_details, facebook_comments, or video_summarize. There is no when-to-use or when-not-to-use framing for tool selection.

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