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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile needs no restating. The description adds useful behavioral context by disclosing the shape of the payload returned, which matters because there is no output schema. It says nothing about failure modes such as an invalid or unauthorized company_id.

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. The content inventory comes first and the call-to-action prerequisite is front-loaded as the final sentence, so an agent gets the what and the when immediately.

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?

With no output schema, the description compensates by enumerating exactly what fields the response contains, including the nested per-year exchange-rate method and status. Combined with non-destructive read-only annotations and a fully documented single parameter, an agent has everything needed to call this correctly.

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?

There is only one parameter and schema description coverage is 100%; the schema already explains that company_id is a UUID sourced from list_my_companies. The description adds no additional semantics beyond that, so the baseline of 3 applies.

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 a specific resource (the company's foreign-currency setup) and enumerates its scope precisely: activation flag, home currency, activated currency list, and per-accounting-year exchange-rate method and status. That level of specificity separates it from the sibling list_available_currencies, which is a catalog rather than a company configuration.

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 an explicit trigger — call this before answering any question about using, adding or converting currencies — which covers the common entry points for currency-related tasks. It does not state when-not to use it or name an alternative tool, so it falls short of the top score.

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