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 supported chains, pricing ($0.003 USDC per call via x402), the exact return shape, and an example output. It does not cover rate limits or error behavior, but otherwise provides strong behavioral context.

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 front-loaded with the core purpose and return fields, then adds usage, pricing, and an example. The example output is lengthy but earns its place by concretely showing the return shape; no sentence is purely redundant.

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 two-parameter read-only tool with no output schema, the description is complete: it covers supported chains, returned fields, cost, intended use, and a concrete output example. An agent has everything needed to decide and invoke 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 coverage is 100%, so both the hash format and chain enum are already documented. The description's chain list and example output add marginal value but do not provide syntax or format details beyond the schema, making baseline 3 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?

The description names a specific verb and resource ('Transaction decoder') and enumerates the exact fields returned (status, from, to, value, gas used, fee, method, transfers, approvals). This clearly distinguishes it from siblings such as wallet_balance, token_info, and gas_estimate.

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?

It gives a clear use case: 'Use to confirm a payment landed or explain what a transaction did.' It does not name alternative tools or state when not to use it, so it falls short of explicit routing guidance.

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