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

With no annotations, the description carries the full burden. It discloses cost ($0.005 USDC per call via x402 on Base), the not_found behavior for unknown hashes, and lists the exact return fields. It implies a read-only operation but does not explicitly state that, nor does it mention rate limits or authentication. Still, the provided behavioral details are substantial and accurate.

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 two sentences, front-loaded with the core return fields, followed by a usage rationale, then the error/cost details. Every sentence adds value with zero fluff, and the most critical information (what it returns and when to use it) comes first.

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?

Although there is no output schema, the description explicitly lists the return fields (status, block, sender, recipient, value, gas used, fee paid, logs emitted), covers error handling (not_found), and notes the cost and payment mechanism. For a simple tool with two parameters, this is a complete and self-contained description.

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 100%: both 'hash' and 'chain' have clear descriptions, including an example and default. The tool description adds no additional parameter semantics beyond reinforcing that 'hash' is the transaction hash and 'chain' defaults to base. Since the schema already covers everything, baseline 3 is appropriate.

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?

Clearly states the tool returns transaction status (success, failed, pending) along with a detailed list of fields (block, sender, recipient, value, gas, fee, logs). This verb+resource specification distinguishes it from siblings like address_info or token_info, which are about other entities.

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?

Provides an explicit use case: 'Use to confirm an action you took really settled rather than assuming it did.' This gives clear context for when to invoke the tool. It does not explicitly state when not to use it, but the sibling tools are clearly different domains, so there is no ambiguity about alternatives.

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