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

Annotations already cover safety (readOnlyHint, idempotentHint, closed world), so the description's job is additional behavior — and it delivers: pagination mechanics, the shape and types of returned fields, and a licensing/attribution obligation. The only gap is that it never states range defaults or how large a full series can be.

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 purpose, then pagination, then the return fields — a sensible order. The field enumeration is compact, though the trailing attribution sentence is long and the 'next_cursor/cursor' naming could be tightened.

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 compensates by listing every returned field and its type, plus pagination and attribution requirements — enough for an agent to consume results correctly. It stops short of clarifying date-range semantics (date vs date_gte/date_lte) or default limits, but the schema covers those.

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 all seven parameters are documented in the schema and the baseline is 3. The description restates the same series codes rather than adding syntax or filter-combination guidance, and it names 'next_cursor' while the actual parameter is 'cursor', a small mismatch inherited from the schema wording.

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+resource ('Policy rate and exchange rates per day') and names the concrete datasets via the series codes, so an agent knows exactly what it retrieves. It does not explicitly differentiate from siblings like swestr or consumer_prices, but the resource is specific enough that confusion is unlikely.

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 implied (query policy/exchange rate series by date) and the description gives one concrete procedural hint ('pass next_cursor to get the next page'). There is no statement of when to prefer this tool over alternatives or any exclusions, leaving context to inference.

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