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

Annotations already cover the safe/read-only, idempotent, open-world profile, and the description adds substantive behavior on top: newest-first ordering, the de-duplication rule that a merger or failure appears once from whichever side the CERT was on, branch-level suppression, and historical coverage start dates. These are exactly the semantics an agent cannot infer from structured fields.

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?

Front-loaded with verb, key, and ordering, and every subsequent clause carries non-redundant information (dedup rule, branch exclusion, historical limits). The first sentence is dense and long, but no sentence is disposable.

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?

Output schema exists, so return shape need not be described; the description instead covers ordering, de-duplication, event-type filtering effects, and temporal coverage. Nothing an agent needs in order to call this 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%, so the baseline is 3; the description earns an extra point by explaining that event_types controls the otherwise-hidden branch-level records and by clarifying the from/to scope as coverage windows rather than mere filters. It doesn't add format detail, but here the schema already fully documents the parameters.

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 first clause names a specific verb (get), a scoped resource (one institution's structure-change history, keyed by CERT) and an ordering (newest first). It then enumerates the event families covered, so the agent can tell this apart from fdic_search_failures or fdic_search_institutions without opening a 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?

It gives clear usage context: branch-level events are excluded unless event_types includes branch, and merger/failure coverage windows (1969/1970) are stated. It never explicitly routes to a sibling (e.g., when to use fdic_search_failures instead), so it stops short of the exclusion-and-alternatives bar.

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