affaan-m/ECC · error · JsonRpcError

-32602

-32602

Error message

Invalid arguments for ${toolName}.

What it means

Every tools/call's arguments pass through validateArguments, which requires a plain object and dispatches to a per-tool AJV validator from TOOL_VALIDATORS. Non-object arguments or schema violations throw JsonRpcError -32602 with the message 'Invalid arguments for <toolName>.' (optionally appended with up to three problem descriptors: instancePath + keyword).

Solutions

1. Read the appended problem descriptors (instancePath/keyword) to find the offending field
2. Ensure arguments are a JSON object matching the tool's inputSchema (check the tools/list output)
3. Add missing required fields or fix types (e.g. scopes must be an array of enum strings)
4. Update the client to the tool's current schema if the tool evolved

Example fix

// before
{ "name": "memory-save", "arguments": "fix auth bug" }
// after
{ "name": "memory-save", "arguments": { "content": "fix auth bug", "scope": "project" } }

if (args === null || typeof args !== 'object' || Array.isArray(args)) throw new Error('arguments must be a JSON object matching the tool inputSchema');

const isRecord = (v) => typeof v === 'object' && v !== null && !Array.isArray(v);

try { return await client.callTool({ name: tool, arguments: args }); } catch (e) { if (e.code === -32602 && /Invalid arguments/.test(e.message)) { const schema = (await client.listTools()).tools.find(t => t.name === tool).inputSchema; console.error('Expected schema:', JSON.stringify(schema)); throw e; } throw e; }

When it happens

Trigger: Calling a memory tool with arguments that are not a record (null, array, string), or an object failing the tool's JSON schema (missing required fields, wrong types, bad enum values).

Common situations: Client sends stringified JSON instead of a parsed object; required field like 'query' or 'content' omitted; scope passed as a string instead of an array; tool renamed so its old argument shape no longer validates.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• MCP config must include an mcpServers object
• artifact path must be a non-empty relative path
• assets must be a nonempty list
• built an invalid spec
• Canonical session snapshot must be an object

AI-assisted analysis of affaan-m/ECC@8321021c54 (2026-09-16). Data as JSON: /api/errors/35b4728cf7cb6f02. Report an issue: GitHub.

Appendix: source

Thrown at scripts/memory-mcp.mjs:257

    isError: true,
  };
}

function jsonRpcResult(id, result) {
  return { jsonrpc: JSONRPC_VERSION, id, result };
}

function jsonRpcError(id, code, message) {
  return {
    jsonrpc: JSONRPC_VERSION,
    id: id ?? null,
    error: { code, message },
  };
}

function validateArguments(toolName, value) {
  if (!isRecord(value)) {
    throw new JsonRpcError(-32602, `Invalid arguments for ${toolName}.`);
  }
  const validate = TOOL_VALIDATORS.get(toolName);
  if (!validate(value)) {
    const problems = (validate.errors || [])
      .slice(0, 3)
      .map(error => `${error.instancePath || '/'} ${error.keyword}`)
      .join(', ');
    throw new JsonRpcError(
      -32602,
      `Invalid arguments for ${toolName}${problems ? `: ${problems}` : ''}.`
    );
  }
  return { ...value };
}

function executeMemoryTool(name, rawArguments, options = {}) {
  const security = resolveServiceSecurity(options);
  const input = validateArguments(name, rawArguments);

View on GitHub (pinned to 8321021c54)