Meta ad accounts

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

Annotations already declare readOnly, idempotent, non-destructive, open-world. The description adds genuinely new behavioral context: under a client registry only the client's own accounts are returned and others are counted in not_owned_hidden, which tells the agent the listing can be incomplete. It stops short of covering pagination or rate limits, so not 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?

Two short paragraphs with zero waste; the scoping constraint and returned fields are front-loaded and the downstream consumer (meta_insights) is named immediately.

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 compensates by naming the returned fields, and it covers the one optional parameter's effect via the registry note. Nothing an agent needs to invoke and interpret this read-only listing correctly is missing.

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 client_id parameter is fully documented there ('Client id from clients_list; empty uses the only client'). The description's registry sentence adds indirect context but no new syntax or format guidance, 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?

States a specific verb and resource ('List the Meta ad accounts the access token can read') and enumerates the returned fields (id act_..., name, status, currency, timezone). This clearly distinguishes it from sibling account-listing tools such as gads_accounts and openai_ads_account.

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?

Explicitly routes the agent: use it to find the account id for META_AD_ACCOUNT_ID or the account_id argument of meta_insights. It also states the conditional behavior when a client registry is in play, so the agent knows when results will be scoped rather than complete.

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