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

Annotations already declare readOnly, idempotent, open-world, non-destructive behavior. The description goes beyond that by disclosing the payment model ($0.02/call via x402), the auth path (prepaid x-credit-token header), the free tier (1 call/day), and that no API key is needed — genuinely useful operational 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?

Front-loaded with purpose and output fields, then billing details. Reasonably tight, though the enumerated return fields partially duplicate what the output schema already provides.

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 decode tool with a full output schema and rich annotations, the definition covers input, output shape, and access/pricing prerequisites. The only gap is the absence of guidance distinguishing it from overlapping transaction-lookup siblings.

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?

With a single 'hash' parameter at 100% schema coverage, the schema already carries the semantics. The description only restates 'Required input: hash' and adds no format, chain, or validation 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?

States a specific verb ('Structural decode') and resource ('any Base transaction'), and enumerates the exact fields returned (from/to, ETH value, status, gas used, block, method selector, nonce). It is clear what the tool does, but it never differentiates itself from close siblings like base_tx, receipt_parse, or ai_tx_explain.

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: give a hash, get a decoded summary. There is no explicit statement of when to prefer this over base_tx, base_receipt, or ai_tx_explain, and no exclusion criteria. Paid/free conditions are stated but those concern billing, not tool selection.

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