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

Annotations only declare readOnlyHint and openWorldHint; the description adds the material commercial and behavioral facts an agent cannot get elsewhere: it costs $0.004 USDC on Base via x402, payment must be passed in _meta["x402/payment"], and the operation is deterministic. It also gives a concrete example output object so the response shape is known.

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?

Content is dense and front-loaded with purpose, then return fields, then pricing. The opening two clauses are redundant ('Transaction status on Base. Status of a transaction on Base, Ethereum...'), costing a sentence that could be merged.

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 inline example output carries the return-value burden well, and the chain coverage, status values, determinism, and x402 payment mechanics cover everything an agent needs to invoke this correctly.

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% and both parameters are documented there, so the baseline of 3 applies. The description repeats the chain list and shows hash in the example output but adds no syntax, format, or default detail beyond the schema.

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+resource (transaction status) and enumerates exactly what is returned: pending/success/failed, block, confirmations, from/to, gas used, log count. The phrase 'Deterministic, no LLM' implicitly separates it from the sibling ai_tx_explain, so an agent can distinguish the two without opening a schema.

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?

Usage is only implied: 'Deterministic, no LLM' hints this is the raw-data path versus ai_tx_explain's interpretation, and the supported-chain list scopes it. There is no explicit when-to-use/when-not statement or named alternative, leaving the agent to infer the routing.

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