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

With no annotations, the description carries the burden and does disclose key behavior: this is a simulation over past prices (read-only, no side effects), it costs 0.002 USDC per call, and it names the returned metrics. It stops short of describing pagination/limits or the full 402 handshake, though the schema's paymentProof field covers that flow.

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, zero waste: the simulation behavior and outputs come first, the cost disclosure follows. Nothing is repeated or padded.

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?

With no output schema, the description usefully enumerates the return fields (invested, value, average cost, return), and the payment model is stated. The gap is the two undocumented scheduling parameters, whose meaning must be guessed from defaults alone.

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 60%: pair, amount, and paymentProof are documented, but days and everyDays have no descriptions. The description's 'fixed amount' and 'on a schedule' loosely map to amount and everyDays, but it never clarifies that everyDays is the buy interval or what days controls, leaving the untyped-in-schema params under-specified.

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 ('Simulates buying a fixed amount of a crypto pair on a schedule over past daily prices') and even names the outputs. No sibling tool does DCA backtesting, so differentiation is implicit but the purpose is unambiguous.

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 the use case (backtesting a DCA strategy on historical prices) and mentions the per-call cost, which is real usage context. However, it never says when to prefer this over alternatives like compound_interest or percent_change, and gives no exclusions or prerequisites beyond the payment hint.

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