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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=true), and the description adds context beyond them: the specific contents returned (parents, subsidiaries, merger/transformation history) and data provenance from FFIEC NIC and the FDIC directory, which hints at coverage limits. It does not address behavior for unknown RSSD ids or missing hierarchy data, keeping it short of a 5.

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?

Two short sentences, front-loaded with the resource and scope; the source attribution in parentheses is compact and informative. Nothing is redundant or padded.

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, non-destructive lookup with no output schema, the description supplies what the response contains (the hierarchy plus merger history) and its provenance, which is the main thing an agent needs. Remaining gaps — depth of the hierarchy, ordering, and behavior when no parent/subsidiaries exist — are minor.

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?

With a single parameter and 100% schema description coverage, the schema already defines rssd_id as a Federal Reserve RSSD id with an example. The description adds only that the identifier addresses exactly one bank, and does not clarify whether other ids (e.g., FDIC cert numbers) are accepted or rejected.

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 resource and scope: 'Full ownership hierarchy for one bank: parent(s), subsidiaries, and NIC merger/transformation history.' That cleanly distinguishes it from profile/branch siblings, though it never names the closely related 'structure' tool as the lighter alternative, so the 'Full' qualifier does the differentiation implicitly.

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?

Usage is only implied — 'Full' suggests this is the deep variant and 'for one bank' signals single-entity scope, so an agent can infer it should be chosen when the complete corporate tree is needed. There is no explicit when-to-use/when-not statement and no pointer to the sibling 'structure' tool.

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