check_blacklist - djd-agent-score-mcp

Check Fraud Blacklist

check_blacklist

Read-onlyIdempotent

Check Ethereum wallets for fraud reports. Verify reputation and view detailed report counts before transacting to assess address risks.

Instructions

Check if a wallet has any fraud reports filed against it.

PAID endpoint — requires x402 payment ($0.05 USD).

Args:

wallet (string): Ethereum wallet address to check

Returns: { wallet, reported, reportCount, reports[] }

Input Schema

TableJSON Schema

Name	Required	Description	Default
`wallet`	Yes	Ethereum wallet address (e.g. 0xAbC...123)

Implementation Reference

src/tools.ts:224-257 (handler)

The handler function and registration for the 'check_blacklist' tool. It takes a wallet address, makes an API request to '/v1/data/fraud/blacklist', and returns JSON with wallet blacklist status, report count, and detailed reports.

  // 5. check_blacklist ────────────────────────────────────────────────
  server.registerTool(
    "check_blacklist",
    {
      title: "Check Fraud Blacklist",
      description: `Check if a wallet has any fraud reports filed against it.

PAID endpoint — requires x402 payment ($0.05 USD).

Args:
  - wallet (string): Ethereum wallet address to check

Returns:
  { wallet, reported, reportCount, reports[] }`,
      inputSchema: { wallet: WalletSchema },
      annotations: {
        readOnlyHint: true,
        destructiveHint: false,
        idempotentHint: true,
        openWorldHint: true,
      },
    },
    async ({ wallet }) => {
      try {
        const data = await apiRequest<BlacklistResponse>({
          path: "/v1/data/fraud/blacklist",
          params: { wallet },
        });
        return ok(JSON.stringify(data, null, 2));
      } catch (error) {
        return err(error);
      }
    }
  );

src/tools.ts:24-27 (schema)
The WalletSchema Zod validation schema used for the check_blacklist tool input. Validates Ethereum wallet addresses with regex pattern requiring 0x prefix and 40 hex characters.
```
const WalletSchema = z
  .string()
  .regex(/^0x[a-fA-F0-9]{40}$/, "Must be a valid Ethereum address (0x + 40 hex chars)")
  .describe("Ethereum wallet address (e.g. 0xAbC...123)");
```

src/types.ts:123-133 (schema)

The TypeScript interface BlacklistResponse defining the output structure for the check_blacklist tool, including wallet, reported status, report count, and detailed reports array.

export interface BlacklistResponse {
  wallet: string;
  reported: boolean;
  reportCount?: number;
  reports?: Array<{
    reportId: string;
    reason?: string;
    txHashes?: string[];
    createdAt: string;
  }>;
}

src/tools.ts:225-226 (registration)
The tool registration point where 'check_blacklist' is registered with the MCP server using server.registerTool().
```
server.registerTool(
  "check_blacklist",
```

Tool Definition Quality

A4.3/5.0

Behavior4/5

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

Annotations cover safety (readOnlyHint, destructiveHint, idempotentHint), but the description adds critical behavioral context: the payment requirement ($0.05 USD) and the return structure ({ wallet, reported, reportCount, reports[] }). Since no output schema exists, documenting the return format is valuable added transparency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is well-structured with clear sections (purpose, cost warning, args, returns) and front-loaded with the core function. Every sentence serves a distinct purpose—cost warning prevents accidental invocation, and returns documentation compensates for missing output schema. No redundant or wasted text.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given this is a single-parameter read operation with rich annotations covering safety properties, the description is complete. It appropriately compensates for the missing output schema by detailing the return object structure, and includes the critical payment context necessary for successful invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 100% schema description coverage, the baseline is 3. The description lists 'wallet (string): Ethereum wallet address to check' which largely repeats the schema's description ('Ethereum wallet address (e.g. 0xAbC...123)'). It does not add semantic details beyond what the schema's pattern and description already provide.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The first sentence 'Check if a wallet has any fraud reports filed against it' provides a specific verb (Check), resource (fraud reports), and target (wallet). It clearly distinguishes from sibling 'report_fraud' by specifying this is a read/check operation rather than a write/submit operation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides crucial usage constraints by noting it is a 'PAID endpoint — requires x402 payment ($0.05 USD)', which informs the agent about cost prerequisites. However, it does not explicitly contrast with sibling 'report_fraud' (e.g., 'use this to verify before reporting') or specify when-not-to-use scenarios.

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

Install Server

djd-agent-score-mcp

Check Fraud Blacklist

Instructions

Input Schema

Implementation Reference

Tool Definition Quality

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