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

Annotations already declare this to be a read-only, non-destructive, open-world call, yet the description adds the material detail the annotations omit: per-currency access tiers, with only USD being keyless and all others requiring a subscription. It also discloses that results are the original official rows rather than derived/classified data, which shapes interpretation of the payload. Return format and pagination behavior are not covered, keeping it at 4.

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 sentences, with the resource and the key differentiator front-loaded and the access constraint stated immediately after. Every clause carries information; there is no filler or repetition of the schema.

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 an output schema present, the description does not need to describe return values, and it covers the one non-obvious runtime hazard (subscription gating per currency). For a three-parameter read tool this is close to complete; only pagination behavior and the currency universe are left unstated, both of which the schema largely handles.

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%, so every parameter (currency, limit, offset) is already documented in the schema, and the description adds no syntax, defaults, or bounds beyond that. Its only extra signal is scoping the archive 'for a currency', which is a baseline 3 under high coverage.

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 uses a clear verb ('Return') on a specific resource ('public central-bank press-release archive for a currency') and explicitly states what the rows are not ('without derived sentiment or indicator classifications'), which separates it from derived-data siblings like risk_sentiment or indicator_query. It stops short of naming a sibling tool outright, so it falls just below a 5.

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 access note ('USD keyless; others: subscription_required with a subscribe link') tells the agent when a call will be gated and implicitly routes to subscribe_for_mcp_access, which is genuinely actionable. However, there is no guidance on when to prefer this over adjacent news/release tools such as latest_announcements, macro_news, or release_calendar, so tool selection is left to inference.

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