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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds behavioral context on the data shape (OHLCV) and supported time ranges. It does not disclose the response format, behavior for invalid tickers, or whether prices are adjusted for splits/dividends, but with annotations carrying the safety burden, the added context is sufficient for a baseline 3.

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 core purpose is front-loaded in the first sentence, followed by a concise range statement and then example queries. The example list is slightly long (four examples plus a catch-all), but each example is short and adds practical routing value for an agent. Nothing is wasted.

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 low-complexity tool with three parameters and annotations covering the safety profile, the description is largely complete: it names the returned data concept (OHLCV), the supported ranges, and typical query phrasings. The main gap is the lack of an output schema combined with no mention of the exact response structure, but naming the OHLCV fields partially compensates.

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% — symbol, period, and interval each have documented descriptions and period/interval have enums. The description adds light value by linking period concepts to real queries (e.g., 'what was the stock price last month?' maps to period=1mo, '1-minute' maps to interval=1m), but the schema already does the heavy lifting, so the baseline 3 applies.

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 and resource ('Get historical stock price data') and enumerates the data fields (open, high, low, close, volume). It conveys the temporal scope (intraday through multi-year). It distinguishes from siblings like stock_quote and stock_compare implicitly through the word 'historical' and the example queries, but it never names an alternative explicitly, so it stops short of a 5.

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 provides concrete example queries ('how has AAPL performed this year?', 'show me the price chart for Tesla', 'what was the stock price last month?') that clearly signal when to invoke this tool versus stock_quote or stock_compare. However, it does not state when NOT to use it or name alternative tools for current pricing, so exclusions are missing.

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