phacility/phabricator · error · PhutilProxyException

Invalid parameter information was passed to method '%s'.

Error message

Invalid parameter information was passed to method '%s'.

What it means

When parameters come as a single 'params' POST field, Phabricator decodes its contents with phutil_json_decode(). Failure raises a PhutilProxyException whose message names the Conduit method and which wraps the underlying PhutilJSONParserException carrying the exact parse error and offset.

Source

Thrown at src/applications/conduit/controller/PhabricatorConduitAPIController.php:691

        }
        $params[$key] = $decoded_value;
      }

      $metadata = idx($params, '__conduit__', array());
      unset($params['__conduit__']);

      return array($metadata, $params, true);
    }

    // Otherwise, look for a single parameter called 'params' which has the
    // entire param dictionary JSON encoded.
    $params_json = $request->getStr('params');
    if (phutil_nonempty_string($params_json)) {
      $params = null;
      try {
        $params = phutil_json_decode($params_json);
      } catch (PhutilJSONParserException $ex) {
        throw new PhutilProxyException(
          pht(
            "Invalid parameter information was passed to method '%s'.",
            $method),
          $ex);
      }

      $metadata = idx($params, '__conduit__', array());
      unset($params['__conduit__']);

      return array($metadata, $params, true);
    }

    // If we do not have `params`, assume this is a simple HTTP request with
    // HTTP key-value pairs.
    $params = array();
    $metadata = array();
    foreach ($request->getPassthroughRequestData() as $key => $value) {
      $meta_key = ConduitAPIMethod::getParameterMetadataKey($key);

View on GitHub (pinned to 5720a38cfe)

Solutions

1. Build the params payload with your language's JSON encoder (json_encode/json.dumps) instead of by hand.
2. Inspect the wrapped PhutilJSONParserException (or run the payload through a JSON linter) to find the exact syntax offset.
3. Replace bespoke HTTP calls with arc call-conduit, which encodes parameters correctly.

Example fix

# before
$ curl -d 'params={"query":phabricator}' https://phab.example.com/api/phabricator.macro.query
# after
$ curl -d 'params={"query":"phabricator"}' https://phab.example.com/api/phabricator.macro.query

# Always build the params field with an encoder, never string templates.
import json
body = 'params=' + requests.utils.quote(json.dumps(params))
requests.post(url, data=body,
              headers={'Content-Type': 'application/x-www-form-urlencoded'})

When it happens

Trigger: curl -d 'params={"query":phabricator}' with an unquoted string or trailing comma; client code assembling the params string via string concatenation or printf with unescaped values; a shell mangling quotes so the body arrives truncated or altered.

Common situations: Hand-written curl incantations in scripts or wiki docs; clients that 'look right' but interpolate quotes incorrectly when values contain quotes or newlines.

Related errors

• The value for parameter '%s' is not valid JSON. All paramete
• Use form-encoded data to submit parameters to Conduit endpoi
• Error while reading "%s": %s
• Invalid JSON input.
• Service "%s" is unrecognized, restricted, or you do not have

AI-assisted analysis of phacility/phabricator@5720a38cfe (2026-08-21). Data as JSON: /api/errors/b44c17c898551154. Report an issue: GitHub.