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

The readOnlyHint annotation already signals that the tool is read-only. The description adds that it is a 'Free tool' and specifies the query mechanism, but it does not disclose return format, pagination, or rate limits, which would be useful beyond the annotation.

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?

The description is a single sentence, front-loaded with the 'Free tool' tag, and directly states the action, query inputs, and output granularity without redundant 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?

With no output schema and a nested filters object, the description conveys the essential query logic but lacks information about the response structure or edge cases. The readOnlyHint annotation mitigates safety concerns, but the description could be more complete for a tool with six parameters.

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?

The input schema already documents all parameters with descriptions (100% coverage). The description emphasizes filters.region_ids and filters.time.granularity as the core drivers, reinforcing their importance, but adds minimal meaning beyond the schema's parameter descriptions.

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 clearly states the tool queries the currency pack using specific filters (region_ids, time.granularity) and returns daily, weekly, or monthly FX data. This specific verb+resource+output distinguishes it from siblings like get_catalog and get_pack.

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 the tool is for FX rate queries by detailing the exact filters and granularity options. It does not explicitly exclude use cases or reference sibling alternatives, but the context is sufficiently clear that an agent can infer when to use it.

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