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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds behavioral context beyond this: it mentions pricing ($0.04 per call), usage limits (free call per day), authentication requirements (x-credit-token header, no wallet/API key), and the nature of the output (risk read, notes). It also states it 'turns raw calldata into an answer,' providing a clear behavioral trait. No contradiction 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 front-loaded with the core purpose in the first sentence, followed by supporting details. It is somewhat verbose with pricing and authentication information, but each sentence adds value for an agent deciding whether to call it. It is not overly long and maintains a clear structure.

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?

Given that an output schema exists (not shown), the return format is presumably documented there. The description covers the input requirement, the type of analysis, pricing, and access constraints. It does not mention potential error conditions or limitations, but combined with annotations and schema, it is adequately complete for an agent to invoke it 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?

The input schema has 100% coverage with the description 'Transaction hash,' and the tool description only repeats that a hash is required. It does not add format details, examples, or constraints beyond what the schema already conveys. Per the calibration, with high schema coverage, a baseline of 3 is appropriate; the description adds no additional parameter meaning.

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 clearly states the tool's purpose: providing a plain-English explanation of a Base transaction given a hash. It specifies the action (explain), the resource (Base transaction), and the output (action, risk read, notes). However, it does not explicitly distinguish itself from sibling tools like base_tx or tx_decode, relying on the unique 'plain-English' angle without naming alternatives.

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 says what the tool does but provides no guidance on when to use it versus alternatives. It does not mention conditions like 'use when you need a human-readable summary' or exclude cases where tx_decode or receipt_parse would be more appropriate. No explicit when-to-use or when-not-to-use instructions are given.

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