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

With no annotations, the description carries the full burden and does disclose the access model: 0.005 USDC per call via x402 PAYMENT-SIGNATURE or free with an API key, with auto-pay noted. It does not cover failure modes (invalid asset, reversed dates) or caching, so it is strong but 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?

Front-loads the definition, then the usage rationale, then the access terms in a bracketed block. The middle sentence ('a return with nothing to compare it against does not answer whether the strategy was worth running') is slightly rhetorical but does real work as justification.

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, but the description states what comes back (a percentage) and covers cost and auth, which is most of what an agent needs. The one gap is the asset-vs-token-triple alternative addressing scheme, left to the schema to hint at.

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 the baseline is 3. The description adds nothing about the parameters beyond the general concept of an asset and a date window, and does not clarify how the optional base_token/quote_token/market_data_venue triple relates to the required asset field.

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 ('Buy-and-hold return for an asset between two dates, as a percentage') with the unit of the return spelled out. It also explicitly separates itself from run_backtest, which already embeds the same metric for its own window.

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 a concrete trigger ('use it whenever you state what a strategy returned') and names the alternative plus the exact condition that selects it ('call this for a different asset or a different period'). No inference required.

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