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

No annotations are supplied, so the description carries the full burden. It does disclose a genuinely useful behavioral trait — a cost of 1 credit — plus the default series behavior, but says nothing about return format, data frequency, latency, or error behavior for unknown series codes.

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 dense sentence with the resource named first and cost appended in parentheses — nothing is padded. The trailing 'and more' is slightly vague, but overall the structure is front-loaded and efficient.

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 three-parameter read tool with no annotations and no output schema, the definition covers the identifier space but leaves the return shape (dates, values, units, frequency) entirely unexplained. Adequate to invoke, thin for interpreting results.

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 coverage is 100%, so the baseline is 3, but the description earns an upgrade: the schema only says 'string, comma list allowed' for series, while the description supplies real series identifiers and identifies the default. It adds no extra detail on from/to beyond the schema's YYYY-MM-DD format.

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: retrieving Bank of England database series, with three concrete series identifiers (IUDBEDR, XUDLUSS, IUMBV34) that make the data domain unmistakable. It does not distinguish itself from the overlapping siblings fx_rates, hmrc_exchange_rates, or ons_timeseries, which is why it falls short of 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 description implies usage by naming example series codes and marking IUDBEDR as the default, but never says when to choose this over fx_rates or ons_timeseries, nor when a date range is required. With all parameters optional, the agent gets no guidance on what happens if it calls with no arguments.

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