BoE base rate on a date

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

With no annotations present, the description carries the burden of explaining behavior. It transparently states that the tool returns the rate in force on the given date and also provides the effective date of that level. This goes beyond a simple 'gets a rate' by disclosing the additional returned value, though it leaves out minor details like error conditions or boundary behavior.

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?

The description is a single, front-loaded sentence. It states the action ('Get'), the resource ('Bank of England base rate'), the qualifier ('on a specific historical date'), and the additional output ('when that level took effect') with no filler or redundant wording.

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?

For a simple one-parameter lookup tool with an output schema present, the description provides the core purpose and one key behavioral detail. It is sufficient for an agent to understand what this tool does and when to invoke it. However, it could be more complete by noting that it is for point-in-time lookups rather than range queries, but this is a minor gap given the simplicity.

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?

The input schema already documents the single 'date' parameter with type, pattern, and description, so schema coverage is 100%. The description repeats that it is a historical date but adds no syntax or format details beyond the schema. This aligns with the baseline 3 for well-covered schemas where the description need not compensate.

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 begins with 'Get the Bank of England base rate' which is a specific verb and resource, and immediately narrows scope to 'a specific historical date' plus 'when that level took effect.' This clearly distinguishes it from sibling tools like get_current_rate (current rate) and get_rate_history (history/range), making the tool's purpose unmistakable.

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?

No explicit guidance is provided about when to use this tool versus alternatives. It is evident from the description that it takes a specific date, but there are no exclusions, comparisons to sibling tools, or notes on edge cases. The tool names suggest overlap with get_rate_history and get_current_rate, but the description does not address this.

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