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 useful context that results are permission-scoped ('the user can advertise with') and act as a prerequisite for ad creation, but says nothing about the shape or size of the result set.

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 compact sentence with no filler, and the resource is front-loaded before the dependency note. It is efficient, though the semicolon clause could have been used to name an alternative tool instead of repeating the ad-creation dependency.

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 read-only lookup with no output schema, the description should at least hint at what comes back (page IDs/names used later in ad creation), since the whole point is to obtain identifiers. It covers the input side adequately via the schema but leaves the return contract implicit.

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% with three well-documented parameters, including the enum for language and the account ID format hint, so the schema carries the burden. The description adds no parameter meaning at all, which lands it at the baseline 3.

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 names a concrete resource (Facebook Pages plus linked Instagram accounts) and its scope (the ones the user can advertise with), so an agent knows it retrieves ad-eligible pages rather than general account data. It does not explicitly say 'list/retrieve' or distinguish itself from nearby siblings such as list_accounts or meta_account_status, which keeps it below a 5.

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 clause 'needed to create ads' implies the usage context: fetch page/IG identity before calling meta_create_ad or meta_create_campaign. There is no explicit when-not guidance and no named alternative (e.g., list_accounts for ad accounts), so the routing signal is implied rather than stated.

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