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

Annotations already mark readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds behavioral context by listing the exact computed metrics returned ('monthly average return, median return, win rate, sample size, dispersion, and per-year monthly returns') and noting the data source ('from stored FX or gold series'). No contradiction.

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?

Three sentences, front-loaded with the action, then usage triggers, then return metrics. Every sentence earns its place; no filler or repetition of schema content.

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 an output schema present and annotations covering side effects, the description provides enough information: what data is used, what metrics are returned, and when to use it. It covers the key aspects an agent needs to select and invoke the tool correctly.

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%: all four parameters have descriptions and examples. The description adds a minor semantic cue that the data is pre-stored seasonality, but doesn't extend beyond schema for parameter meaning. Baseline 3 applies 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 opens with 'Get monthly return seasonality for an FX pair or XAU/USD', a specific verb+resource combination. The scope is clear and distinct from sibling tools like forex or commodities, mentioning seasonal patterns, month-of-year tendency, and win rate. It clearly states what the tool does.

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 second sentence gives explicit use triggers: 'Use this when the user asks for seasonal patterns, month-of-year tendency, historical monthly win rate, or XAUUSD/gold seasonality.' This is clear context for when to invoke the tool, though it doesn't explicitly name alternatives or exclusions.

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