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

With no annotations, the description carries the full burden and does reasonably well: it discloses the look-back cap, defaults, supported chains/tokens, the event taxonomy, and the return structure. It also notes the x402 payment model and price, which is unusual and useful context. Gaps remain on event-volume limits, data latency, and error behavior.

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?

Front-loaded with the trigger condition, then compactly organized into Input/Output/Example/Price labels, so an agent can scan it fast. It is dense to the point of being telegraphic ("Example: ?days=1"), and the pricing sentence sits awkwardly at the tail.

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?

There is no output schema, and the description compensates by enumerating the returned event fields, per-token counts, and live frozen status. Combined with the parameter constraints and the issuer-vs-sanctions caveat, an agent has enough to call this correctly and interpret results.

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 coverage is already 100%, so baseline would be 3, but the description adds real meaning: days is constrained to 1-7 with a default of 1, chain values are enumerated (all, ethereum, base), and address is clarified to also return live frozen status per token rather than only filtering events. Token-level filtering is left comparatively thin.

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?

Names a specific resource and scope: issuer freezes (blacklist, unblacklist, destroy_funds) for USDC, EURC on Ethereum/Base and USDT on Ethereum, plus live frozen status for an address. It explicitly distinguishes itself from a sanctions list, separating it from siblings like sanctions_address and token_controls.

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?

"Use when an agent needs recent issuer freezes ... or whether an address is frozen now" gives a clear triggering condition, and "Issuer action, not a sanctions list" implicitly routes sanctions questions elsewhere. It stops short of naming the specific alternative tools (sanctions_address, token_controls) as explicit substitutes.

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