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

No annotations are provided, so the description carries the burden. It adds real value by disclosing the signed EIP-191 attestation return type and the single-chain (Base) scope, plus the free-vs-paid channel. It omits auth requirements, rate limits, failure/error behavior, and what happens for unconfirmed hashes.

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?

Two sentences, front-loaded with the capability before the pricing/channel aside. The second sentence borders on marketing but does convey the free-vs-paid access model, which is actionable.

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 one-parameter tool with no output schema, the description is fairly complete: it names the chain, the check performed, and the return payload. It still leaves the relationship to verify_tx_multi_source and failure semantics unstated.

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 100% schema coverage on the single txHash parameter, the schema already documents the '32-byte transaction hash' format. The description adds no format, encoding, or validation nuance beyond it, so baseline 3 applies.

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 ('Checks'), resource ('Base transaction hash'), scope ('confirmed on-chain'), and return value ('signed EIP-191 attestation'). It does not, however, distinguish itself from the sibling verify_tx_multi_source, which an agent could easily confuse it with.

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 'Free via MCP' versus pay-per-call note gives channel/pricing context, but it never says when to choose this tool over verify_tx_multi_source or when the single-source check is sufficient. Usage is implied rather than guided.

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