get_price_summary

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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, so the safety profile is covered. The description adds meaningful behavioral context beyond annotations: results are in the asset's own currency, ratios are expressed as fractions (0.12 means 12%), and it explicitly lists the returned metrics. This gives the agent a clear picture of output semantics without contradicting annotations.

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 composed of four short, purposeful sentences. The core purpose is front-loaded, followed by usage guidance, alternatives, and a final clarifying note about ratio format. Every sentence contributes new information; there is no fluff or redundancy. It is well-structured for quick scanning.

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?

For a read-only tool with no output schema, the description explains what the user will get: total and annualized return, annualized volatility, max drawdown with dates, and data coverage. It also specifies currency and ratio format, so an agent knows exactly what response to expect. Combined with the explicit usage guidance and alternatives, nothing essential is missing.

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% — every parameter has a clear description, including the period's behavior ('Lookback ending at `end`. Ignored when `start` is given.'). The tool description does not add extra meaning beyond the schema; it restates 'over a period' but does not clarify syntax or relationships beyond what schema already provides. With full coverage, the baseline of 3 is appropriate.

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 a specific verb and resource: 'Measure one asset's performance over a period' and then enumerates exact metrics (total/annualized return, volatility, max drawdown with dates, data coverage). It explicitly distinguishes itself from siblings by naming compare_real_return for inflation/US-dollar/gold terms and compare_assets for multiple assets, so an agent can immediately tell which tool fits.

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 gives an explicit when-to-use rule: "Use it for 'how did X do' questions." It also names two alternatives and the conditions that select them (inflation/US-dollar/gold → compare_real_return; several assets → compare_assets). This is direct, actionable guidance with no ambiguity.

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