Street rate history

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

With no annotations provided, the description carries the full burden and does well: it discloses the inclusive UTC day semantics, a hard 400-day-per-call limit, the default date range tied to the user's plan, and the shape of returned data (rate, buy, sell, confidence per day plus summary). It omits rate limiting, error behavior, and exact plan-tier constraints, keeping it from a 5.

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 dense sentences, front-loaded with the core purpose, followed by limits and defaults. Every clause (inclusive/UTC, 400-day cap, output fields, default range) adds actionable information with no filler.

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?

An output schema exists, so return values needn't be spelled out, yet the description still summarizes them usefully. With 100% schema coverage and only four parameters, the definition is nearly complete; the remaining gap is the absence of any routing to sibling tools for current-rate or comparison use cases.

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 is 100%, so the baseline is 3. The description adds meaningful semantics beyond the schema: it clarifies that from/to dates are inclusive UTC days, that a single call may cover at most 400 days, and that omitting both dates yields a default 30-day window up to the latest day of the plan.

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+resource ('Daily street rates of a currency') with clear scope (between two dates, inclusive, UTC, max 400 days) and lists the returned fields. It implicitly distinguishes itself from get_street_rate by offering a daily history rather than a single current rate, but never names the sibling explicitly.

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 explains defaults (last 30 days up to the latest day of your plan) but gives no guidance on when to use this tool versus alternatives like get_street_rate for a current rate or get_official_vs_street for comparisons. There are no explicit when/when-not conditions.

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