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

Annotations already cover safety (readOnlyHint, destructiveHint=false), so the description adds cost and limit behavior: $0.01/call, 25 free calls, failed calls free, repeats not free, and a 100-log return cap. That is genuine value beyond the structured fields, though it does not discuss result completeness when the 100-log cap is hit or rate limiting.

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?

It is a single dense paragraph, front-loaded with what the tool does and what it returns, with the alternative and pricing deferred to the end where they belong. It is somewhat overstuffed with payment mechanics ('via x402 USDC or a card key (/credits)') for a one-sentence description.

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?

With no output schema, the description carries the burden of describing returns, and it does ('up to 100 logs with block, transaction hash and topics'), plus limits, cost, and the checkout alternative. An agent has enough to call this correctly; only the behavior at the 100-log truncation boundary is 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?

Schema coverage is 100%, so all three parameters are already documented, including the 1-1000 range and default 50. The description restates the block range and clarifies that topic0 is a 0x 32-byte event signature hash, which only marginally extends the schema's wording, plus one address example.

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 states a specific verb and resource ('Recent contract event logs on Polygon PoS (eth_getLogs)') along with the scope (last N blocks, optional topic0 filter) and explicitly names the sibling it is not ('for one transaction's outcome use polygon_receipt'). An agent can distinguish this from polygon_receipt, polygon_tx, and polygon_token_transfers without opening a schema.

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?

It gives concrete use cases ('watch transfers or contract events') and an explicit routing rule to an alternative for the adjacent case (polygon_receipt for one transaction's outcome). The only gap is no guidance on choosing between polygon_logs and polygon_token_transfers, but the named alternative is the one an agent is most likely to confuse.

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