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

Annotations already establish a safe, read-only, closed-world operation, so the bar is lower. The description adds genuinely useful context beyond them: results are cached/snapshot edges that may be incomplete, a negative result is not proof of absence, and the call is OAuth-safe. The cryptic 'OAuth-safe' phrasing is the only weak spot.

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?

Very short and front-loaded: purpose first, then the selection rule, then the caveats. Telegraphic fragments like 'OAuth-safe' are slightly under-explained, but nothing is wasted.

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?

An output schema exists, so return-value detail is unnecessary here. For a four-parameter lookup, the description covers the selection rule and the key data-quality caveat; only per-parameter value formats are 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 coverage is 0%, so the schema itself says nothing about the four parameters; the description carries the load. It names all four and adds the crucial exclusivity constraint (exactly one, never asset ID plus FB user), but it does not explain the expected value format or semantics of each identifier.

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 ('Read cached BM links') and clarifies that the data comes from a cached snapshot. An agent can tell what it returns, though it does not name a sibling (e.g. assets_list_businesses) as the alternative for non-link data.

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?

Gives an explicit selection rule: choose exactly one of business_id, ad_account_id, page_id, or FB-user identity, and never combine an asset ID with an FB user. It also tells the agent how to interpret a miss ('no match does not prove no relationship'). It stops short of naming sibling tools or stating when this lookup is preferred over them.

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