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

With no annotations, the description carries the full burden and does well: it discloses the required wallet signature and its exact message format, a 7-day age limit, single-use-per-tx semantics, and the api_key-omission behavior for key issuance. It omits failure modes and whether the credit is immediately reflected in balance, keeping it from 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 what the tool does, then the hard requirements, then the operational limits. No redundant restatement of the name or 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?

For a state-changing tool with no annotations and no output schema, the description covers prerequisites, constraints, and idempotency well enough to call correctly. What it returns on success (credited balance vs. a new key) and error behavior remain unstated.

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 0%, so the description must compensate, and it does for most parameters: signature gets an exact format string, api_key gets an explicit omission rule, and chain/tx_hash are shown composing that signature. The chain enum values themselves are only visible in the schema, and tx_hash format is not elaborated.

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?

States a specific verb and resource: credit a stablecoin transfer that lacks a matching order or has a non-exact amount. The scope qualifier ('no matching order') implicitly separates it from create_topup/verify_topup, but it never names those siblings explicitly, so the differentiation is left to inference.

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?

Clearly establishes the triggering condition — only for transfers without a matching order or with a non-exact amount — which is a real usage rule. It stops short of naming the alternative tools (create_topup, verify_topup) or stating when not to use this one.

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