Get daily exchange rate time series

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

No annotations exist, so the description carries the full burden. It does add real context: plan gating and the one-entry-per-day shape of the result. It omits what happens with large ranges, empty intervals, response size/pagination behavior, and error conditions, which matter for a date-range query tool.

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, front-loaded with the capability and followed by the access constraint; no filler. It is arguably under-sized for a tool with zero annotation coverage, but nothing in it is wasted.

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 annotations and no output schema, the description should be richer. It covers the plan requirement and output granularity, but leaves the agent without guidance on range limits, large-response behavior, or failure modes for a tool that can return 1000+ entries per day.

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%, and each parameter is already documented with format, defaults, and plan-dependent base behavior. The description adds nothing about parameters beyond restating the two dates and the currency set, so baseline 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?

States a specific verb and resource (returns daily exchange rates), the scope (one or more currencies, between two dates) and the granularity (one entry per day). It is distinguishable from get_latest_rates and get_historical_rates by the daily-series framing, but it never names them, so differentiation is left to inference.

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 only usage signal is the eligibility constraint (Professional plan and above), which is genuinely useful for deciding whether to call. There is no explicit guidance on when to pick this over get_historical_rates or get_fluctuation, and no exclusions or alternatives are named.

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