Load FX rates (X-Operator-Token)

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

Annotations already declare readOnlyHint=false, idempotentHint=true and openWorldHint=true, so the write nature and idempotency are covered upstream. The description does add real value by stating there is no server-side dry run and that confirm gates execution, but it omits what the write does to existing rate data (upsert versus replace) and what the token requirement actually entails beyond the title's parenthetical.

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 the action and the write gate. The parenthetical repeats of the auth header and HTTP path sit in the title and the first sentence respectively, which is mild redundancy but costs little.

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 mutating tool with no output schema, the description conveys the confirmation gate and the absence of a server-side dry run, which is the critical safety information. It still leaves an agent guessing about overwrite semantics for existing rates, limits on batch contents, and the auth-token requirement, which is meaningful for a write that can carry 1000 records.

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 sits at 67%, and the confirm and idempotencyKey properties already carry their own descriptions that the body text only echoes. The nested body.rates array — up to 1000 base/quote/date/rate entries — is described nowhere beyond raw JSON Schema patterns, so the description does not compensate for the coverage gap, though the schema constraints themselves are reasonably expressive.

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 states a specific verb and resource ("Load FX rates") and pins the endpoint (PUT /v1/fx-rates), which unambiguously identifies a write of rate data. It does not, however, distinguish this from the sibling fx_list or explain what loading actually does relative to that read tool.

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?

It gives a concrete execution precondition — nothing is sent unless confirm: true — which tells the agent how to actually run the tool versus previewing. It offers no when-to-use/when-not guidance and never points at fx_list as the read-side alternative, so selection against siblings is left to inference.

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