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

Annotations already declare readOnlyHint=true/openWorldHint=true/destructiveHint=false, and the description adds genuinely new context: explicit pricing ($0.01/call via x402 USDC or card key, first 25 free, failed calls free) and the statement that each call is charged so repeats are not free — which explains the idempotentHint=false annotation. It also clarifies 'reads or computes only and changes nothing.' It does not describe pagination, row caps, or error responses, so it is not exhaustive.

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 opening clause front-loads resource and return shape, then use cases, then cost/behavior — a sensible ordering with little filler. The pricing sentence is dense and mixes payment channels, free-tier, and failure policy in one breath, but every element is actionable.

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 3-parameter tool with no output schema, the description covers purpose, use cases, return fields, cost model, and side-effect profile, which is nearly everything an agent needs to invoke it correctly. Gaps are minor: no guidance on symbol ambiguity (company name vs ticker), no note on response size for max-range queries, and no error semantics beyond 'failed calls free.'

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% and both enums document every allowed value including the intraday ~60-day lookback, so the schema carries the parameter semantics. The description restates the axis bounds ('1-minute to monthly bars over 1 day to the full history') and adds an example symbol, but contributes no format details, symbol-resolution rules, or range/interval compatibility guidance beyond 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?

States a specific verb and resource — OHLCV price history for any ticker or company name — and enumerates the returned fields (open, high, low, close, adjusted close, volume plus first/last/change/high/low). It is clearly distinguishable from siblings like stock_quote (a point quote) and polymarket_price_history (prediction markets).

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?

Gives concrete use cases — chart a stock, backtest a signal, compute returns, feed indicators — plus a worked example (symbol=AAPL), which tells the agent exactly when this tool fits. It stops short of naming the sibling to use instead for a current quote (stock_quote) or for token prices, so routing between near-neighbors is left partly to inference.

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