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

Annotations already declare read-only, idempotent, non-destructive, so the safety profile is covered. The description adds real semantic content beyond that: unchecked items are listed and must never be read as unchanged, plus the paid model ($0.01, half for holders) and crew provenance. It does not state cost of latency or any rate limits, so not a 5.

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 'Use when', then the changed-surface list, then two short routing/payment sentences. Dense but every clause carries information; the enumeration is long yet each item is a distinct checked surface.

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?

No output schema exists, and the description compensates by describing the return shape: per-change before/after values, block numbers, links, and an explicit list of checks that failed to run. For a paid read tool with three params, an agent has everything needed to invoke and interpret it.

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 the baseline is 3; the description still adds the payment flow ordering ('Pass the x402 payment as payment', and the schema's omit-to-get-terms pattern is reinforced by 'Free first' sibling routing). The holderWallet pricing explanation lives mostly in the schema, so credit is limited but present.

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: what changed on an Ethereum ERC-20 token or Uniswap v4 hook since the previous observation, then enumerates the surfaces checked (owner/admin, proxy upgrades, bytecode, pause, fees, supply, liquidity). This is clearly distinguishable from watchtower_watch (ongoing watching) and watchtower_sample (free sample) named in the text.

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?

Explicit trigger condition ('Use when an agent needs to know what changed ... since the previous observation') plus an explicit alternative: 'Free first: watchtower_sample.' The agent knows both when to call this and what to try before paying.

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