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

Annotations provide readOnlyHint and openWorldHint, but description adds useful behavioral context: mined transactions are cached, and there is a cost of $0.001 USDC. This goes beyond annotations by disclosing performance expectation and cost, which is critical for an agent. No contradictions with annotations.

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?

Three short, information-dense sentences. Front-loaded with the core function, followed by supported chains, caching, and cost. No redundant language or fluff.

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 simple two-parameter tool with annotations and no output schema, the description provides adequate context: mainnet scope, chain options, caching behavior, and cost. It doesn't describe return structure, but 'structured decode' implies a schema, and the simplicity reduces the need for more. Slight gap in explaining 'mined txs' meaning confirmed transactions, but not critical.

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%, but description compensates by explicitly mentioning 'by hash' for tx_hash and 'Supports Base, Ethereum, Solana' for chain, mapping directly to the enum values. It also adds that the hash is for a mainnet transaction. While it doesn't detail hash format, the basic semantics are clear and align with 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?

Clearly states it performs a 'structured decode of any mainnet transaction by hash', with explicit supported chains (Base, Ethereum, Solana). This distinguishes it from siblings like decode_calldata, which likely focuses on calldata only. The verb 'decode' and resource 'transaction' are specific and unambiguous.

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?

Implies usage: any mainnet transaction by hash, and lists supported chains. However, it does not explicitly state when to prefer this over decode_calldata or other alternatives, nor does it mention exclusions (e.g., testnets). The mention of 'mainnet' and supported chains provides context, but lacks explicit alternative guidance.

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