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

Annotations only cover read-only/open-world safety, so the description carries the rest and does so well: page size (eight), ordering (newest first), the cursor round-trip, the caveat that `title` holds the accessibility caption rather than post text, and the 1-credit cost.

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 front-loaded sentences: what it returns, how pagination works, then the title-semantics caveat and cost. No filler and the most surprising detail (caption-as-title) is called out explicitly.

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 still tells the agent the shape of results (8 per page, newest first, cursor), the notable field quirk, and the cost — everything needed to call and page through 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 coverage is 67%, and `url`/`cursor` are already documented in the schema. The description confirms the cursor flow and re-emphasizes public pages, but `cache_max_age` remains undocumented in both places, so it doesn't fully compensate.

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+resource: photos from a public Facebook Page's photo grid. The scope (public pages only, photo grid) makes it clearly distinct from siblings like facebook_pagePosts, facebook_pageReels, or facebook_profileEvents.

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 'public Page' constraint and pagination flow imply when this is appropriate, but no sibling is named and no when-not guidance is given (e.g., posts vs reels vs photos). Usage is implied rather than routed.

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