Tools for agents: Strict JSON text decoder

Connect with MCP

{
  "mcpServers": {
    "super-agent-tools": {
      "url": "https://app.getsupers.com/sites/agent-strict-json/mcp"
    }
  }
}

Use this URL in any client supporting remote Streamable HTTP MCP. Calls return structured JSON; inputs are processed without persistence.

Call decode_strict_json

Input is JSON text inside the text argument, not an already parsed value. Exactly one root value is allowed, including scalars and null, with optional surrounding JSON whitespace. Duplicate decoded object keys fail at any nesting level, including escape-equivalent names. NaN, Infinity, -Infinity and float overflow fail. Unpaired Unicode surrogates in decoded keys or values fail; valid escaped surrogate pairs are accepted. Check valid: successful null has value:null; rejected input has no value. Syntax errors include a zero-based Unicode code-point offset and one-based line/column; only LF advances line count. Duplicate, numeric and Unicode validation errors do not claim source locations and report the first encountered failure, not every defect. Integers use runtime arbitrary precision subject to its digit limit; decimal/exponent numbers use binary64 rounding and may underflow to zero. This is not exact decimal parsing, JSON Schema validation, canonicalization, JSON5, comment stripping or automatic repair. Deep nesting and oversized integer literals return decoder_limit. Input is never executed or persisted.

{
  "name": "decode_strict_json",
  "title": "Strict JSON text decoder",
  "description": "Decode a single JSON value, rejecting duplicate keys, nonfinite numbers and unpaired surrogates. Return explicit valid/value or valid/error with syntax location when available.",
  "inputSchema": {
    "properties": {
      "text": {
        "title": "Text",
        "type": "string"
      }
    },
    "required": [
      "text"
    ],
    "title": "decode_strict_jsonArguments",
    "type": "object"
  },
  "outputSchema": {
    "additionalProperties": true,
    "title": "decode_strict_jsonDictOutput",
    "type": "object"
  },
  "icons": null,
  "annotations": {
    "title": null,
    "readOnlyHint": true,
    "destructiveHint": false,
    "idempotentHint": true,
    "openWorldHint": false
  },
  "meta": null,
  "execution": null
}

Run the example to see the actual result.

HTTP alternative

POST https://app.getsupers.com/sites/agent-strict-json/call
Content-Type: application/json

{
  "text": "{\"agent\":\"builder\",\"result\":null,\"ready\":true,\"steps\":[1,2]}"
}

The HTTP and MCP interfaces execute the same implementation. Validation errors are returned explicitly. See the tool notes above for its supported inputs and behavior.