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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and non-destructive, so safety is covered. The description adds one genuinely useful behavior — that an empty allowed list means all accounts — but says nothing about what happens when no Facebook account is connected, whether results are paginated, or what fields come back.

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 sentence with no filler, and the core resource is front-loaded while the permission caveat is attached in a compact parenthetical. Nothing could be removed without losing meaning.

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 zero-parameter read with no output schema and strong annotations, the description covers the essential questions: what it lists and how to interpret the allowed-accounts signal. It is slightly thin on the return shape and on the error/empty case, but an agent can call it correctly from what is given.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The parenthetical clarification about empty allowed lists is model-level semantics rather than parameter documentation.

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 (list the ad accounts the connected Facebook account reaches) and adds a second dimension: which accounts agents are permitted to use. An agent can tell this apart from generic connection tools like list_connections or get_pages, though it never explicitly names those siblings.

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?

Implicitly suggests this is the tool to consult before acting on ad accounts when permissions matter, but it gives no explicit when-to-use or when-not-to-use guidance and does not name an alternative for cases where a different listing tool applies. Usage is inferable, not stated.

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