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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds value by disclosing the shape of each record (id, code, rounding) and that exchange rates are conditional on a validity date, but says nothing about pagination behavior, total counts, or error/empty cases.

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 short sentences, front-loaded with what the tool returns and followed by the one actionable hint about currency_id. No padding or redundant restatement of the title.

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?

There is no output schema, so the description usefully names the fields the agent will receive, and all four parameters are documented in the schema. For a simple read-only list endpoint this is close to complete; only pagination/result-set guidance is absent.

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 the baseline is 3. The description goes slightly beyond it by tying the exchange rate to a date ('valid on a date'), clarifying the relationship between the date and with_exchange_rate parameters rather than treating them independently.

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 names the specific resource (currencies set up in bexio) and enumerates the returned fields (id, code such as CHF/EUR, rounding), which distinguishes it from sibling list tools like bexio_list_accounts or bexio_list_taxes. It is a noun phrase rather than an explicit verb, but combined with the title 'List currencies' the intent is 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?

'Use an id as currency_id' gives useful cross-tool guidance on what to do with the returned id, and the optional exchange rate implies when to pass date/with_exchange_rate. However, there is no explicit statement of when to call this versus alternatives, and no mention of prerequisites or any case where you should not call it.

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