Cross-Post to Facebook Page & Instagram

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

Annotations are all false, so the description carries the full burden. It discloses the mutation (creates posts), the parallel execution with Promise.allSettled (one failing doesn't block the other), the conditional behavior (text-only yields FB only), and the return value (results from both platforms). This is thorough behavioral transparency beyond what annotations provide.

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 well-organized with clear sections (Requires, Args, Logic, Returns) and front-loaded with the core purpose. It is slightly long but every sentence adds value, so it earns a high score for structure rather than being terse.

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 tool publishing to two platforms with multiple media types, the description covers the main behaviors and return format. It lacks precise guidance on edge cases like both image and video provided, but the core use cases are documented. Given no output schema, the described return is sufficient.

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%, but the description adds significant meaning: it specifies that 'message' is used as both FB post text and IG caption, that image_url creates photo posts on both, video_url creates Reels, and it explains the response_format parameter. This adds semantics well beyond the schema's one-line descriptions.

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 ('Publishes') and resource ('both a Facebook Page and Instagram simultaneously'), clearly distinguishing it from single-platform tools like meta_create_post. It also names the two platforms and the simultaneous nature.

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?

It provides a clear prerequisite (meta_list_pages must be called first) and details the logic for image, video, and text-only inputs, which tells the agent when this tool is appropriate. However, it does not explicitly compare against alternative sibling tools for single-platform publishing, so the guidance is good but not exhaustive.

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