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

With no annotations at all, the description carries the full disclosure burden, and it does so thoroughly. It states the three return values, reveals that counts, required JSON fields, and sums are checked in code, notes that payment_tx is verified on chain, and fully explains the unusual x402 payment flow including the PaymentRequired error and retry mechanism. Cost is also disclosed. This is exemplary transparency.

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?

The description is longer than average, but every sentence earns its place—core function, return behavior, cost, and the non-obvious payment protocol are all necessary. The structure is front-loaded with the tool's main purpose, followed by return semantics and then payment details, which is a logical and efficient ordering.

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?

This is a paid, externally-dependent tool with no output schema and no annotations, so the description must cover invocation, cost, and return values—and it does all of these. It even explains the client-side payment retry protocol and how to use the fallback npm client, leaving little room for guesswork. The term 'verify_externally' is not expanded, but it is reasonably self-explanatory given the context.

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 baseline is 3. The description adds meaningful value beyond the schema: it clarifies that payment_tx is verified on chain and that checks in code cover counts, required JSON fields, and sums, which gives task and deliverable real semantic weight. This justifies a point above baseline.

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 opens with a precise verb-resource pair: 'Checks work another agent handed back against the task it was given.' It clearly explains the purpose and the pre-payment/escrow context, and the unique return values (accept, reject, verify_externally) help separate it from vague siblings like 'check' and 'result'. However, it never explicitly names a sibling or contrasts itself, so it stops just short of full differentiation.

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 description gives clear trigger conditions: 'before you pay, release escrow, or pass it on.' It also explains how to invoke payment, either through an x402-aware MCP client or the npm client, which is important operational guidance. But it does not discuss when to prefer alternative sibling tools or what would make this tool inappropriate, so it lacks explicit when-not guidance.

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