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

Adds real context beyond the readOnly/openWorld annotations: the exact metric windows returned (1M/3M/6M/1Y/3Y/5Y and 1M/52W/5Y) and the cost of '1 request unit', which no annotation conveys. Slightly terse on what happens with an invalid symbol, but the safety profile is already carried by 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?

Dense and front-loaded — every sentence adds a distinct fact (output fields, benchmark semantics, alternative tool, cost). The telegraphic 'performance is… highLow is…' phrasing is efficient rather than sloppy, though slightly abrupt.

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 safety, the remaining burden is usage and cost, both addressed. An agent knows when to call it, what fields to expect, and what it costs; little 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 coverage is 100%, so 3 is the baseline; the description goes further by explaining that benchmark values add relative-return columns for each symbol listed, which turns a comma-separated string into a predictable output shape. The behavioral consequence of the parameter is clearer than the schema alone.

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 (period returns, highs and lows for one SYMBOL.EXCHANGE) and immediately delineates why it isn't the sibling 'prices' tool. The scope is precise enough that an agent can distinguish it from all 20+ siblings without reading the schema.

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?

Explicitly says to omit benchmark for absolute figures only and to use prices for the daily price series — a named alternative with the condition that selects it. Both the when and the when-not are covered.

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