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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful non-schema context: the $0.008 per-page billing rate and the fact that results include engagement metrics and reaction breakdowns. It does not mention pagination or rate limits, keeping it short of a 5.

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?

Three tight sentences: what it does, what it returns, the optional filter, and the cost. Nothing is wasted and the core purpose plus the pricing signal are front-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?

With no output schema, the description carries the return-value burden and does so (post text, engagement, reactions, media). Annotations cover the read-only/open-world safety profile, parameters are fully documented in the schema, and the cost model is disclosed — an agent has everything needed to call 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 description coverage is 100%, so the baseline is 3 and the schema already documents pages, page_id, start_date, end_date and get_sentiment. The description still adds meaning by tying page_id to its origin tool and reiterating that date filtering is optional, plus the per-page billing linkage — modest but real value beyond the schema.

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?

States a specific verb and resource ('Get posts from a Facebook page'), pins the input to a numeric page ID sourced from facebook_page_details, and enumerates the returned content (post text, engagement metrics, reaction breakdown, media). This cleanly separates it from siblings like facebook_group_posts, facebook_page_photos, facebook_page_reels, and search_facebook_posts.

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?

Gives clear context: fetch posts for one known page, optionally narrowed by date range, with the page ID obtained from facebook_page_details. It does not name exclusions or alternatives (e.g., search_facebook_posts when the page is unknown or keyword search is wanted), so it stops short of full when/when-not guidance.

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