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

The description significantly expands on the annotations by noting 'DATA ONLY, read-only, no HMAC required, no network, no orders, no wallet/account access.' This adds crucial safety and scope details that align with readOnlyHint=true and openWorldHint=false. No contradiction exists.

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 description is compact and efficient, front-loading the action and scope. Every sentence adds value—purpose, implementation fidelity, and safety. No redundancy or verbosity.

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?

The description covers safety and high-level purpose well but lacks details about the output structure or parameter behavior. Since there is no output schema, the agent is left uncertain about what metrics are returned or how to interpret results. Adequate for a simple calculator but not fully complete.

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?

With 0% schema description coverage, the description must compensate for parameter understanding. It only mentions 'returns' explicitly and leaves period, risk_free, and annualization unexplained. This forces the agent to infer semantics from the empyrical metric context, which may be insufficient.

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 clearly states the tool 'runs' an 'empyrical-style metrics calculator over supplied returns,' with a specific verb and resource. It distinguishes from sibling run tools by emphasizing metrics calculation on returns and the pure TS reimplementation of empyrical 0.5.5 conventions.

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 clear context for when to use the tool: to compute bounded, permissionless empyrical metrics from returns, with no HMAC or network access. However, it doesn't explicitly list alternatives or state when not to use it, so it falls short of a 5.

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