x402 crypto market structure

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It adds useful context beyond the schema, such as the 7-year data limit and 5,000-bar cap per call, which are behavioral traits. However, it lacks details on error handling, rate limits, or data freshness, leaving gaps for a mutation-free tool.

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 appropriately sized and front-loaded, with three concise sentences that each add value: the first defines the data, the second sets constraints, and the third suggests use cases. There is no wasted text, making it efficient and well-structured.

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?

Given the tool's complexity (read-only data retrieval with two parameters), no annotations, and no output schema, the description is mostly complete. It covers purpose, constraints, and use cases, but lacks details on output format or error scenarios, which would be helpful for full completeness.

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?

The schema description coverage is 100%, so the schema already documents both parameters (token and limit) fully. The description does not add any parameter-specific semantics beyond what the schema provides, such as examples or format details, resulting in the baseline score of 3.

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's purpose with specific verbs and resources: 'Daily OHLCV price history with buy/sell flow data' identifies what data is retrieved, and 'Up to 7 years of daily bars, up to 5,000 bars per call' specifies the scope and constraints. It distinguishes from siblings like history1h and history5m by emphasizing daily frequency.

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 this tool: 'Good for backtesting and trend analysis' suggests appropriate use cases. However, it does not explicitly state when not to use it or name alternatives (e.g., history1h for hourly data), which prevents a score of 5.

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