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

The description discloses that this is a paid operation ('Pay 10000 atomic USDC on Base via exact x402') and explains the effect of include_high_resolution. It does not explicitly state whether the operation is read-only or has side effects, but the delta/polling nature implies a read-style operation.

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 well-structured, consisting of three sentences that cover the trigger, the return behavior, and the payment requirement. It avoids redundancy and front-loads the key usage condition.

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 has four parameters and a payment requirement, the description provides sufficient context for an agent to know when to call it, what to pass, and what to expect (delta items, nextCursor, possible empty items). The output schema is present, so no further detail is needed.

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 descriptions for since, cursor, and include_high_resolution add meaning beyond the raw type definitions, and the tool-level description clarifies that cursor or since must be supplied. maxItems lacks a description, but its min/max constraints are present in the schema, so the gap is minor.

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 that this tool returns material machine-economy changes since a cursor, and positions it as the delta mechanism for a caller that already has a zFinia cursor. It clearly distinguishes it from siblings like public_catalog_offer_evidence by focusing on 'changes since its last cursor'.

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 explicitly instructs to supply either cursor or since, and tells the caller to pass the nextCursor back on the next poll. It also notes that empty items is a valid result, giving concrete guidance on how to interpret the response.

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