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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses critical behavioral details: paid API cost ($0.002 USDC per successful call), payment mechanism (x402 on Base, Solana, or Arc), and that failed calls are not charged. This adds substantial value and does not contradict annotations.

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 a single dense paragraph that front-loads the core purpose and ends with pricing. It is efficient, but the detailed enumeration of return fields is somewhat redundant given the presence of an output schema.

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 complexity (economic calendar with multiple filters and return fields), the description covers all needed aspects: date range limit, filtering, source, and pricing/payment details. The presence of an output schema mitigates the need to explain return values in depth.

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 meanings are fully documented in the schema. The description adds no extra parameter semantics beyond restating the filtering options and date range constraint already present in the schema.

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 states a specific resource (Investing.com economic calendar) and clearly enumerates the returned fields and filtering options, making it immediately clear what the tool provides. It is unambiguous and would allow an agent to distinguish it from unrelated sibling tools.

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 gives clear context (date range up to 7 days, filtering by country, currency, or minimum importance) but does not explicitly name alternatives or when-not-to-use scenarios. Given the absence of similar sibling tools, this context is sufficient for correct selection.

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