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

With no annotations, the description does add real behavioral context: the tool is paywalled at 0.05 USDC via x402 PAYMENT-SIGNATURE header, and API-key clients pay nothing — information an agent cannot get from the schema and that affects whether/how it calls. It says nothing about latency, rate limits, or what an evaluation result contains.

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 tightly written sentences with the capability front-loaded and the access/payment note clearly bracketed as secondary. No filler, though the payment aside is slightly long relative to the core statement.

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 9-parameter tool with a dual live-mode/dataset_key operating model and no output schema, the description does not explain the two modes or the shape of results, relying on the schema to convey mode switching. Adequate but with a notable gap around what an evaluation returns.

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%, so parameter meaning is already fully carried by the schema. The description only adds the high-level notion of optional signals and a date range, which the schema restates; baseline 3 applies.

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 concrete verb (evaluate) and resource (chart data plus optional signal triggers) over a range, so the agent knows it produces evaluations rather than raw data. It does not explicitly differentiate itself from the closely named siblings evaluate_signal and evaluate_strategy, which leaves ambiguity about the multi-signal scope.

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 says what the tool does but never states when to choose it over evaluate_signal (single signal) or evaluate_strategy (strategy-level). The bracketed text covers payment/auth mechanics, not usage selection, so the agent is left to infer the batch-vs-single case from the schema's 'up to 20 signals'.

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