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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the credit cost ('1 credit'), which is genuinely useful context not present in annotations, but says nothing about pagination behavior, result limits, or whether reels and long-form videos are mixed or separate.

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?

A single front-loaded sentence with no filler; the parenthetical credit note is compact and earns its place. It is efficient but borderline terse given the tool's pagination surface.

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?

No output schema exists, so the description carries the burden of return shape; it discloses view counts and credit cost but not pagination via `cursor`, result density, or media type breakdown. Adequate for a simple list tool, but a few gaps remain an agent would want.

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?

With 100% schema description coverage, the schema already documents both `url` formats and the `cursor` provenance. The description adds no parameter-level meaning beyond the schema, so the baseline 3 applies.

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 names the specific resource ('Videos and reels from a profile or Page') and the enrichment returned ('with view counts'), which separates it from facebook_profile_photos and facebook_profile_posts in the sibling list. It is a noun phrase rather than a verb+resource sentence, so it is slightly less crisp than a 5.

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?

There is no guidance on when to pick this over facebook_profile_posts, facebook_profile_photos, or the generic facebook_profile. The implied use case (list a Page's videos) is inferable only from the resource noun, with no exclusions, prerequisites, or alternatives named.

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