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

Goes well beyond the readOnlyHint/openWorldHint/destructiveHint annotations: it discloses the three possible verdicts, that it performs no external lookups, no storage, no receipt, and critically that ALLOW means policy comparison only and is not a compliance/sanctions certification. This is exactly the kind of semantic caveat an agent needs to avoid over-trusting the result.

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-loads the usage trigger, then packs verdicts and scope exclusions into two dense but purposeful sentences. No filler, though the final sentence mixing amount-format and URL-credential rules is slightly compressed.

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?

With no output schema, the description correctly supplies the return values (ALLOW/REQUIRE_APPROVAL/BLOCK) and the safety semantics around them, which is the essential missing piece. Remaining gap is the unexplained acknowledge_unconstrained policy flag given the deep nested schema.

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 0% and the nested objects contain many fields (action.kind/asset/amount/sender/network/resource/recipient, plus policy fields), so the description must carry the load. It usefully specifies decimal amounts vs atomic units, public addresses, and that resource URLs are never fetched and must not carry credentials — but leaves policy fields such as acknowledge_unconstrained and expected_payer unaddressed.

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 verb and resource ('check a proposed payment against explicit rules before sending it') and states the exact decision outputs (ALLOW, REQUIRE_APPROVAL, BLOCK). Explicitly carves out what it is NOT (no send/sign/authorize, no sanctions screening, no compliance certification), which cleanly separates it from the receipt-oriented siblings.

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?

Opens with a direct when-to-use trigger ('Use this when the user wants to check a proposed payment...before sending it') and gives concrete example conditions (amount, recipient, asset, network vs policy/limit). Negative scope ('does not send, sign or authorize') further constrains when this is the right tool.

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