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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered; the description adds genuinely useful context beyond that: ordering (newest first), the lookback window, token defaults, and the x402 payment requirement of $0.004 USDC. The payment/auth model is a behavioral trait the schema and annotations do not express, which is exactly what this dimension rewards.

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?

Three compact sentences with no filler: scope first, use case second, cost last. The first sentence is quite dense (five chained qualifiers), but each sentence earns its place and the most decision-relevant information is front-loaded.

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 read-only tool with no output schema, the description never hints at the shape of the returned records (fields per transfer, whether amounts are raw or decimal-adjusted). Ordering and cost are covered, but an agent cannot anticipate the response structure at all, leaving a meaningful gap.

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 description coverage is 100%, so the schema already documents every parameter with defaults and ranges. The description restates a few of these (default USDC, ~10k blocks, max 30k, 5-token cap) but adds no new syntax or constraint information beyond what the schema provides — baseline 3 is appropriate.

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 ('Recent ERC-20 transfers in and out of an address on Base'), plus scope qualifiers (up to 5 tokens, default USDC, newest first, ~10k block lookback, max 30k). This is clearly distinguishable from siblings like base_tx (single tx detail) and base_erc20_balance (balances rather than transfer history).

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?

'Check incoming payments or wallet activity' gives a clear intended use case, which is more than most descriptions offer. However, it never names an alternative or exclusion — an agent must infer on its own whether base_tx is the better choice for a specific transaction lookup.

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