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

The annotations already declare readOnlyHint, openWorldHint, and destructiveHint, so no contradiction exists. The description adds that the tool returns computed monthly statistics 'from stored FX or gold series', which is useful but does not go beyond the annotation-covered safety profile with details about side effects, auth, or rate limits.

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 compact and well-structured: one sentence states the core function and trigger cases, and a second sentence summarizes the returned metrics. Every clause adds useful information without repetition or 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?

Given the rich parameter schema and the presence of an output schema, the description is complete enough. It names the input domain, the query scenarios, and the key returned fields (average return, median, win rate, sample size, dispersion, per-year monthly returns), so an agent can select and invoke the tool confidently.

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 schema already provides 100% coverage with descriptions for all four parameters: instrument, month, end_date, and lookback_years. The tool description does not add any extra parameter-level meaning, so it stays at the baseline for well-documented schemas.

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 states a specific verb ('Get'), a precise resource ('monthly return seasonality for an FX pair or XAU/USD'), and immediately gives concrete trigger phrases such as 'seasonal patterns', 'month-of-year tendency', and 'historical monthly win rate'. It clearly distinguishes this tool from the broad set of FX and commodity siblings by focusing on seasonality analysis.

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 explicitly says 'Use this when the user asks for seasonal patterns, month-of-year tendency, historical monthly win rate, or XAUUSD/gold seasonality', giving clear usage conditions. It does not name alternative tools or state when not to use it, but the provided trigger list is sufficiently specific for an agent to decide.

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