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

With no annotations, the description carries the burden and delivers the key operational fact: the call is paid (0.01 USDC via x402 PAYMENT-SIGNATURE) or API-key authenticated with zero per-call charge, and auto-pay behavior for capable clients. It omits return format, granularity of candles, and what happens when lookback exceeds available history, keeping it below a 5.

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?

Front-loaded with what the tool returns and when to reach for it, then a compact override-selection sentence, then payment terms in a bracketed aside. No redundant restatement of the name or schema fields.

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?

No output schema exists, and the description implies OHLCV rows without specifying candle granularity, timezone, or truncation behavior for long lookbacks. For a single-required-parameter read tool with full schema coverage and disclosed payment terms, it is otherwise complete enough to call correctly.

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 baseline is 3, but the description adds real meaning: quote_token and market_data_venue must be supplied together to pin an exact market, provider routes to an external source, and omitting all of them falls back to a Mangrove market. That coupling constraint is not present in 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 (daily OHLCV history for one crypto asset) plus scope (1-3650 day lookback). It explicitly distinguishes itself from the current-price path ("reason about past price movement rather than the current spot"), which separates it from sibling get_market_data.

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 clear trigger conditions: price history, chart data, past price movement. It also explains the market-selection decision (quote_token + market_data_venue together, or provider, or omit for the Mangrove default). It never names the alternative tool explicitly, so the routing is implied rather than stated.

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