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

Annotations already declare the read-only, idempotent, non-destructive profile. The description adds genuinely useful behavioral context beyond them: each Page has an independent product status and a partial/degraded overall state does not guarantee every Page is usable. Return format and scoping behavior are still not described.

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 short sentences, front-loaded with what the tool returns, followed by workflow guidance and a status caveat. There is no filler, though 'product status' is slightly jargon-heavy and could be clearer.

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 simple read-only listing tool with one optional parameter and no output schema, the description covers the essential purpose, sequencing, and a meaningful degradation caveat. It does not describe the shape of returned inbox identities or pagination, but those are relatively minor gaps here.

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%, and the single account_id parameter is already well explained in the schema (owned Facebook unipile_account_id, not a person or Page ID). The description adds no parameter-level meaning, 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 states a specific resource and scope: 'Discover personal folders and activated Pages.' This is enough for an agent to recognize it as the inbox/page enumeration tool rather than a chat-listing tool like facebook_list_inbox_chats, though the verb 'discover' is slightly less direct than 'list'.

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 gives clear sequencing guidance: 'Choose the intended identity before reading or answering.' That tells the agent when this call belongs in a workflow. It does not explicitly name alternatives such as facebook_list_inbox_chats or state when not to use it, so it stops short of a 5.

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