fx_history

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It doesn't reveal return format (candles, OHLCV?), whether it returns currency symbols alongside prices, data source or restrictions, or expected data granularity/free-tier limits. The 'has output schema' context signal mitigates somewhat since the output is already structured, but the description itself adds no behavioral context.

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?

A single concise sentence that states the core purpose without padding. It's appropriately minimal, though it could potentially front-load more usage-relevant detail without becoming verbose.

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?

The complexity is moderate (4 params, all optional with defaults, output schema present). With a good output schema and 100% schema coverage, the description is arguably adequate for basic selection. However, the lack of any distinction from sibling asset-class tools and no behavioral context leaves a gap given the tool has zero annotations and many near-siblings.

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% and all four parameters (start, end, symbol, interval) have descriptive schema text with defaults and formats. The description adds no parameter information beyond confirming it's 'currency pair' data, which the schema already states via the symbol example (EURUSD, GBPUSD). Baseline 3 is appropriate since the schema does the heavy lifting.

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 it fetches forex historical price data, with a specific verb ('Get') and resource ('forex currency pair historical price data'). It distinguishes from siblings like stock_history and crypto_history by specifying forex, though it doesn't explicitly note the difference from world_index_history which also deals with forex-related data.

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?

No guidance on when to use this tool vs alternatives. Sibling tools include crypto_history, stock_history, and world_index_history, which could confuse the agent about which asset class to query. The description gives no context on when forex data is appropriate versus exchange-rate-index history.

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