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

Annotations already declare readOnly/openWorld/non-idempotent, but the description adds pricing ($0.01/call via x402 or card key, first 25 free, failed calls free), the charging implication of repeats, and validation behavior. That is exactly the extra context annotations cannot convey.

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 the core action and result shape, then usage, error behavior, example, and pricing. Dense but sensibly ordered; the pricing sentence is lengthy but earns its place for a paid, non-idempotent call.

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?

Without an output schema, the description supplies the result fields (direction, counterparty, amount, transaction), ordering (newest first), and cap (50), plus validation and pricing. Nothing material for correct invocation is missing.

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 token, blocks, and address are already documented. The description largely restates defaults and ranges, adding only a sample address and 'about 2.4 hours' framing, 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 and resource (list a wallet's recent ERC-20 transfers on Linea) plus scope (blocks, up to 50, newest first). Explicitly distinguishes itself from linea_token_balance, so an agent won't confuse it with the balance sibling.

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?

Gives concrete when-to-use cases (confirm a payment arrived, see what was sent) and names the alternative for the current balance. Also states failure behavior (malformed address → 400, uncharged), which helps the agent anticipate errors.

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