Verify an agent's advertised route, price, payment details, and schemas against its live endpoint.
Scored across 1 tool
With only one tool, there is no possibility of overlap or misselection. The tool's purpose is clear and unambiguous.
The single tool uses a clear verb_noun pattern ('verify_agent_contract'). With only one tool, consistency is trivially perfect.
A single tool is on the thin side per the calibration, but the server's narrow purpose—verifying an agent contract against a live challenge—makes it borderline acceptable. It is not excessive, but the surface feels minimal.
The tool covers the core verification action for the stated domain, and repeated calls can handle multiple contracts. Minor gaps exist, such as no ability to retrieve or list contracts separately, but agents can work around this within the narrow scope.
Compare an advertised agent contract with its live x402 challenge.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | Public HTTP or HTTPS agent/API URL. An origin URL may be resolved through discovery metadata. | |
| method | No | Optional method to probe. If omitted, the advertised method is used, then GET as a fallback. | |
| expected_hash | No | Optional previous contract_hash. A mismatch proves the public contract changed. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions the comparison concept and that an expected_hash mismatch proves a contract changed, but it does not disclose whether the tool makes network requests, whether it has side effects, whether authentication is needed, or what a successful or failed verification returns.
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 a single sentence with no filler, and the verb and primary objects are front-loaded. Every word contributes to conveying the purpose.
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 and no annotations, the description should explain what the tool returns, what failure conditions exist, and whether network access is involved; none of that is present. 'Advertised agent contract' and 'x402 challenge' are left undefined, leaving an agent to guess how to operationalize the verification.
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%, and each parameter has a meaningful description in the schema, so the baseline is 3. The description adds domain context around 'advertised contract' and 'live x402 challenge' but does not add operational detail beyond what the schema already provides.
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 uses a specific verb ('Compare') and identifies both resources ('advertised agent contract' and 'live x402 challenge'), going beyond a restatement of the tool name. It is clear enough to know the core operation, though the x402 jargon may be opaque to agents unfamiliar with the domain.
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?
There is no explicit guidance on when to use this tool, what prerequisites exist, or when it should not be used. No sibling tools are present to distinguish against, and the description provides no operational context such as needing discovery metadata or an advertised contract source.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
verify_agent_contractFind and vet x402 payment APIs before your agent pays one: uptime, price, on-chain volume.
Checks whether an ERC-8004-registered agent is actually alive right now via a real MCP handshake
Trust verdict for an x402 payment endpoint: health, 402 handshake, price, proceed/caution/avoid.
Inspect and validate an x402 endpoint before an autonomous agent spends USDC.
Add one secure layer between your agents and this server.
