Yahoo price history (stocks / indices / ETFs / FX / crypto)

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description does not need to cover safety. The description adds that it returns OHLCV and metadata, but does not disclose any further behavioral traits like rate limits, pagination, or additional constraints. With annotations carrying the safety profile, a score of 3 is appropriate.

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 three sentences long with no filler. It front-loads the main output (OHLCV price history) and then provides a clear list of supported symbol types. Every sentence is necessary and informative.

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 relatively simple tool with three parameters and no output schema, the description covers the primary purpose, supported asset types, and the nature of the output (OHLCV + metadata). It does not mention that intervals and ranges are configurable (those are in the schema), but the description is sufficient for an agent to understand the tool's use. It could be slightly improved by noting the flexible parameters.

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 the schema already provides basic descriptions for all three parameters (symbol, range, interval). The description does not add semantic detail beyond listing asset types, which is already implied by the parameter descriptions. Therefore, the description adds minimal value over the schema.

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 provides OHLCV price history and metadata for any Yahoo symbol, and lists supported asset types including equities, indices, ETFs, FX, and crypto. It also explicitly says 'Use this for both stock and index data,' which helps distinguish from potential subset tools, but it does not directly differentiate from siblings like yahoo_quote or yahoo_spark.

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 clear context by listing which symbol types work (equities, indices, ETFs, FX, crypto) and states 'Use this for both stock and index data.' However, it does not mention when to use this tool versus alternatives (e.g., yahoo_quote for current quotes) or provide explicit exclusions.

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