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

With no annotations, the description carries the full load and does well: it discloses error behavior (unscreenable names return 400, never a false clear), transliteration of non-Latin names, and the exact payment/auth mechanism ($0.01 USDC on Base via x402 in params._meta). It omits return shape, latency/rate limits, and whether screening is logged, so it stops short of a 5.

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?

Four compact sentences, front-loaded with the core purpose and the strongest differentiator ("real matching on all three"), with price and endpoint at the end where they belong. The address/batch/watchlist clause is the one part that does not earn its place.

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 3-parameter screening tool with no output schema and no annotations, the description supplies the critical operational facts: cost, payment protocol and chain, HTTP transport, and the fail-closed error contract. Only the return/verdict format and how `days`/`threshold` affect results are left implicit.

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 100%, so the schema already documents names, days, and threshold — baseline 3 applies. The description adds one genuinely useful non-schema detail (the x402 payment location in params._meta) but never explains `days` (the schema calls it "re-screen" look-back) or `threshold`, leaving the two optional tuning knobs understood only from schema text.

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 opening sentence names the specific resource and sources precisely ("Sanctions screening against US OFAC, UK OFSI and EU lists with real matching on all three"), which is more than a restatement of the name. However the follow-up "Screen a name, a wallet address, a batch, or your own watchlist" describes capabilities that clearly belong to the sibling tools check_sanctions__screen / __address / __batch / __watchlist, muddying rather than sharpening what `verdict` itself uniquely returns.

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?

There is no statement of when to call this versus check_sanctions__screen, __address, __batch, or __watchlist. Worse, the enumeration of name/address/batch/watchlist reads as if this tool covers those cases itself, which borders on misleading given those tools exist as siblings.

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