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

Annotations already establish readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuine behavioral context beyond that: derived facts are 'computed from observed decisions only' (a provenance/accuracy caveat) and the response includes 'freshness and data warnings', telling the agent to expect staleness signals rather than raw data.

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?

A single sentence, front-loaded with the scope marker 'One bank:', with no filler. It is dense and slightly list-like, but every enumerated item corresponds to a real returned field, so 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?

With no output schema, the description carries the burden of previewing return contents and does so field-by-field. Gaps remain: nothing about behavior for an unknown or ambiguous bank id, or whether history beyond the last change is retrievable, but these are minor for a read-only one-param tool.

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 description coverage is 100%, and the schema itself documents the accepted bank id forms (slug, name, abbreviation, country), so the baseline of 3 applies. The description's 'One bank:' phrasing reinforces cardinality but adds no format or matching semantics beyond the schema.

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 names the resource (one bank) and enumerates exactly what the payload contains: policy rate and its start date, last observed decision plus statement, next meeting, derived past facts, and data warnings. That is specific enough to distinguish a single-bank snapshot from the list-oriented siblings like upcoming_decisions, though it never explicitly contrasts itself with them.

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?

There is no explicit when-to-use, when-not-to-use, or alternative named. The 'One bank:' prefix implies single-bank scope versus a cross-bank tool, but the agent must infer that on its own, and nothing explains overlap with upcoming_decisions (which also covers meetings).

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