GoogleChrome/lighthouse · error

Gatherer for ${artifactDefn.id} did not support any gather m

Error message

Gatherer for ${artifactDefn.id} did not support any gather modes.

What it means

Thrown by assertValidArtifact in validation.js. A gatherer's meta.supportedModes array must contain at least one valid gather mode ('navigation','timespan','snapshot'). BaseGatherer defaults supportedModes to [] (meaning 'unspecified'), and a gatherer that never declares modes leaves it empty, which is invalid for an artifact gatherer. Lighthouse needs to know in which modes to run it.

Source

Thrown at core/config/validation.js:65

  if (config.categories?.[pluginName]) {
    throw new Error(`plugin name '${pluginName}' not allowed because it is the id of a category already found in config`); // eslint-disable-line max-len
  }
}

/**
 * Throws an error if the provided object does not implement the required gatherer interface.
 * @param {LH.Config.AnyArtifactDefn} artifactDefn
 */
function assertValidArtifact(artifactDefn) {
  const gatherer = artifactDefn.gatherer.instance;

  if (typeof gatherer.meta !== 'object') {
    throw new Error(`Gatherer for ${artifactDefn.id} did not provide a meta object.`);
  }

  if (gatherer.meta.supportedModes.length === 0) {
    throw new Error(`Gatherer for ${artifactDefn.id} did not support any gather modes.`);
  }

  if (
    typeof gatherer.getArtifact !== 'function' ||
    gatherer.getArtifact === BaseGatherer.prototype.getArtifact
  ) {
    throw new Error(`Gatherer for ${artifactDefn.id} did not define a "getArtifact" method.`);
  }
}

/**
 * Throws an error if the provided object does not implement the required properties of an audit
 * definition.
 * @param {LH.Config.AuditDefn} auditDefinition
 */
function assertValidAudit(auditDefinition) {
  const {implementation, path: auditPath} = auditDefinition;
  const auditName = auditPath ||

View on GitHub (pinned to 9515cd4e58)

Solutions

1. Declare the modes your gatherer supports: meta = {supportedModes: ['snapshot']}.
2. Use the appropriate mode(s): 'navigation' for full page loads, 'timespan' for in-page interactions, 'snapshot' for one-off DOM reads.
3. If unsure, 'snapshot' is the safest minimal mode for read-only gatherers.

Example fix

// before
class MyGatherer extends BaseGatherer {
  getArtifact() {...}
}
// after
class MyGatherer extends BaseGatherer {
  meta = {supportedModes: ['snapshot']};
  getArtifact() {...}
}

const MODES = new Set(['navigation','timespan','snapshot']);
function assertSupportedModes(g) {
  const modes = g.meta?.supportedModes || [];
  if (!modes.length || !modes.every(m => MODES.has(m))) {
    throw new TypeError(`Gatherer must declare at least one valid supportedMode`);
  }
}

function gathererHasModes(g) {
  return Array.isArray(g.meta?.supportedModes) && g.meta.supportedModes.length > 0;
}

try { new Config(config, {configPath}); }
catch (e) { if (/did not support any gather modes/.test(e.message)) console.error('Set meta.supportedModes'); throw e; }

When it happens

Trigger: A gatherer extends BaseGatherer (meta.supportedModes defaults to []) but never overrides supportedModes, so the array length is 0. validation.js:65 throws.

Common situations: Writing a new gatherer and forgetting to set meta.supportedModes. Extending BaseGatherer whose default is an empty array. Migrating an old gatherer that used a different modes API.

Related errors

• ${pluginName} supportedModes must be an array, valid array v
• Gatherer for ${artifactDefn.id} did not provide a meta objec
• Gatherer for ${artifactDefn.id} did not define a "getArtifac
• ${pluginName} has an invalid category description.
• ${pluginName} has an invalid category manualDescription.

AI-assisted analysis of GoogleChrome/lighthouse@9515cd4e58 (2026-08-13). Data as JSON: /api/errors/357cea30d7b5271a. Report an issue: GitHub.