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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile needs no restating. The description adds genuinely new behavioral context: a "partial" status still returns the accounts that loaded and errors lists the rest, which tells the agent to handle partial results rather than treat them as failure.

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 sentences, each doing distinct work: scope, call-ordering, and failure semantics. The most important information (what it returns and that it is a prerequisite) is front-loaded with no filler.

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 available, the description usefully documents the partial/errors response shape, covering the return-value burden itself. The main gap is parameter meaning and any pagination or default-listing behavior, which an agent would need to call it 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 description coverage is 0% across three parameters, so the description has to compensate and largely does not. It never explains what platform, accountId, or profileId do here, and its platform list even omits 'x' and 'whatsapp' which the schema enum allows, leaving the filtering behavior ambiguous.

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 and enumerates the four platforms covered (Instagram, Facebook, TikTok, YouTube), which makes it reasonably distinguishable from the many insight/post siblings. It does not, however, explicitly distinguish itself from the near-identical sibling ads_list_accounts, so an agent could still confuse the two list-account tools.

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?

"Call this first: every other account-level tool takes an accountId from here" gives explicit ordering and dependency guidance that no other field provides. It stops short of stating when NOT to use it or naming an alternative list tool, so it is clear context rather than full when/when-not coverage.

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