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

No annotations are supplied, so the description carries the burden and does disclose meaningful traits: the ECB as source, historical range back to 1999, base-currency flexibility, and optional amount conversion. It omits caveats like publication on business days only, rate-limit/auth behavior, and what happens on weekends/holidays, keeping it below a 5.

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, zero filler, front-loaded with the authoritative source and coverage before the usage recommendation. Every clause adds information.

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 described. Combined with an output schema and 4 params, the description covers the essentials, but the symbol-selection syntax and date format are left ambiguous, a minor but real gap for invocation correctness.

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 0%, so the description must compensate. It explains base ('from any base currency'), date ('today or any date since 1999'), and amount ('optional amount conversion') in prose, but never explains the symbols parameter's mechanics (selection syntax, comma separation) or the expected date format, leaving one of four params effectively undocumented.

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 resource (official ECB reference exchange rates) with concrete scope: ~35 currencies, any date since 1999, any base currency, optional amount conversion. An agent can tell this apart from crypto_convert or exchange_ticker because it names the authoritative source and fiat-currency domain.

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?

'Use to convert prices, invoices or salaries between currencies' gives clear positive usage context. It does not name alternatives (e.g., crypto_convert for digital assets vs fx_carry_ranking) or state when not to use it, so it falls short of a 5.

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