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

Beyond the readOnlyHint=true annotation, the description discloses that the data is cached, that snapshot edges may be incomplete, and that a missing match does not prove absence of a relationship or ownership. It also notes 'OAuth-safe,' adding auth context not present in the annotations. These are meaningful behavioral disclosures.

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?

The description is compact and front-loaded: the core purpose appears first, followed by usage constraints, a caveat, and an auth note. Every sentence adds distinct value, with no filler or redundancy.

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 an output schema and no required parameters, the description covers the essential invocation semantics: which identifier to supply, the exclusivity rule, the cached/incomplete nature of the data, and the interpretation of missing results. No critical operational detail 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 coverage is 0%, so the description carries the parameter-semantics burden. It explains that exactly one of business_id, ad_account_id, page_id, or fb_user_label must be chosen and that asset IDs must not be combined with FB-user identities. The parameter names are self-explanatory, and this exclusivity constraint compensates for the empty schema descriptions.

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 states a specific action and resource: 'Read cached BM links,' which clearly identifies this as a read-only lookup of Business Manager relationship data. It does not explicitly name a sibling tool to differentiate from, so it falls short of a 5, but the resource and verb are specific enough to avoid confusion with the broader assets_list_* 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?

The description gives clear operational guidance: choose exactly one identifier, and never combine an asset ID with an FB user. It does not explicitly state when to prefer this tool over alternatives or when not to use it, so it misses the top score, but the selection constraint is a strong usage guideline.

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