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

Annotations already cover read-only, idempotent, open-world, and non-destructive behavior. The description adds valuable context beyond annotations: pricing ($0.02 per call), authentication via x-credit-token header, free tier, no wallet/API key requirement, and that data comes straight from Base RPC. 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?

The description is compact and front-loaded: purpose and outputs in the first sentence, then required input and pricing/auth in the following sentences. 'Required input: hash' is slightly redundant with the schema, but every other part earns its place and nothing is bloated.

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 single-parameter, read-only tool with an output schema and strong annotations, the description is fully adequate. It covers what the tool does, what input it needs, what output to expect, cost, auth, and prerequisites. No missing information would prevent correct invocation.

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% with the single 'hash' parameter described as 'Transaction hash'. The description only restates 'Required input: hash' and 'Provide a Base transaction hash', adding no semantic detail beyond the schema. Baseline 3 applies because the schema already fully documents the parameter.

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?

Description clearly states a specific verb ('decode') and resource ('any Base transaction'), and lists the exact output fields (from/to, ETH value, status, gas used, block, method selector, nonce). It does not explicitly differentiate from siblings like base_tx, base_receipt, or ai_tx_explain, so it loses the top score.

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?

The description gives clear call-level guidance: provide a transaction hash, with pricing and authentication options. However, it does not state when to prefer this tool over alternatives such as base_receipt or ai_tx_explain, nor any exclusion conditions. Usage context is implied but not explicit.

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