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

No annotations are provided, so the description carries the disclosure burden; 'Fetch' plus the enumerated result fields (aliases, motivation, sponsor, targeted industries, trending activity) make clear this is a non-mutating detail read with a rich payload. It omits what happens on a not-found or ambiguous identifier, which is the one behavioral gap for an unannotated tool.

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 with a distinct job: what it fetches, what comes back, and where to route instead. The core verb and scope are front-loaded with no redundant 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?

For a one-parameter read tool with no output schema, the description supplies both the input contract and an explicit field-level picture of the return value, plus sibling routing. Nothing an agent needs in order to call it 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 coverage is 100% and the single parameter already documents the UUID-or-name dual form with the same examples, so the description adds little new semantic detail. It reinforces the identifier resolution workflow, but that is usage guidance rather than parameter meaning.

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 ('Fetch a single Mallory threat actor by identifier') and scopes the return payload ('full detail'). It clearly separates itself from listThreatActors (search/list) and queryApi (relationship pivots), so an agent can choose it without opening the schema.

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 prescribes the alternative when the exact identifier is unknown ('call listThreatActors first to find the exact identifier') and names queryApi for relationship pivots and cross-entity queries. Both when-to-use and when-to-use-something-else are stated.

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