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 safety profile is covered. The description adds a meaningful behavioral detail beyond annotations: 'Results retain the newest points when the byte cap requires truncation.' This discloses truncation behavior, which is non-obvious and important for an agent relying on data completeness. No contradiction with 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?

Two sentences with zero waste. The core purpose is front-loaded, and the truncation behavior is a single additional sentence that earns its place. No redundant phrasing or repetition of schema details.

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 historical data tool with rich annotations (readOnly, idempotent, non-destructive), the description covers the essential behavioral caveat (truncation). The absence of an output schema means the agent doesn't know the exact return shape, but the description's mention of 'timestamped OHLCV' gives a reasonable expectation. It could mention pagination or date-range semantics, but the tool is simple enough that this is adequate.

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 only 33%, so the description carries some burden. The description mentions 'one symbol' and 'OHLCV price history', which adds meaning to the symbol parameter and the overall return type. However, it does not explain the semantics of limit, interval, startDate, endDate, or exchange beyond what the schema already provides. The schema covers symbol and exchange with descriptions, but the date range and interval parameters are left to their names and defaults. The description adds some value but does not fully compensate for the 67% coverage gap.

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 specific resource ('timestamped OHLCV price history'), and a scope ('for one symbol'). It clearly distinguishes this from sibling tools like market.quotes (current prices) and market.options_chain (options data). The mention of OHLCV and one-symbol scope makes the tool's purpose immediately identifiable.

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 implies usage context: it is for historical OHLCV data for a single symbol, which distinguishes it from market.quotes (current prices) and market.screener (multiple symbols). However, it does not explicitly state when to use this tool versus alternatives, nor does it mention any exclusions or prerequisites. The context is clear but the guidance is implied rather than explicit.

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