BSP policy rate

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

Annotations cover the safety profile (readOnlyHint=true, openWorldHint=false), so the description's job is to add context — and it does: it discloses daily caching, points to meta.as_of for fetch time, and notes the corridor carries source links. It stops short of describing staleness tolerance or refresh behavior, but the additions are genuinely useful beyond the annotations.

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 the core answer and structured around the returned fields with parenthetical glosses (ceiling/floor) that earn their place. Slightly verbose in restating field roles that the output schema likely carries, but no wasted sentences.

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?

An output schema exists, so return values need not be spelled out, yet the description still adds the corridor semantics and caching caveat. For a zero-parameter, read-only lookup, nothing an agent needs to call it 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?

Zero parameters, so the baseline is 4; there is nothing for the description to clarify on the input side. The schema is fully documented and requires no compensation.

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 (Get) and resource (BSP policy rate) plus the corridor around it, and immediately distinguishes itself from the sibling get_bsp_key_rates by calling itself 'a focused view for what is the BSP policy rate?'. Field-level naming (policy_rate_percent, lending_rate_percent, deposit_rate_percent) makes the scope unambiguous.

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 framing as 'a focused view for "what is the BSP policy rate?"' tells the agent the use case and implicitly positions it against the broader get_bsp_key_rates. It does not, however, explicitly state when NOT to use it or give an alternative-if-you-want-more directive.

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