mastra-ai/mastra · error · Error

The workingMemory.use option has been removed. Working memor

Error message

The workingMemory.use option has been removed. Working memory always uses tool-call mode.

What it means

The workingMemory.use option ('tool-call' vs 'metadata' modes) was removed; working memory now always operates in tool-call mode. getMergedThreadConfig throws this Error whenever a MemoryConfig contains a workingMemory object with a `use` key, so stale configs fail loudly instead of being silently ignored.

Source

Thrown at packages/core/src/memory/memory.ts:384

    // Only PG vector store will use these parameters
    if (indexConfig && (indexConfig.type || indexConfig.ivf || indexConfig.hnsw)) {
      createParams.indexConfig = {};
      if (indexConfig.type) createParams.indexConfig.type = indexConfig.type;
      if (indexConfig.ivf) createParams.indexConfig.ivf = indexConfig.ivf;
      if (indexConfig.hnsw) createParams.indexConfig.hnsw = indexConfig.hnsw;
    }

    // Request btree indexes on metadata fields used for filtering
    // This avoids sequential scans on large tables when querying by thread_id or resource_id
    createParams.metadataIndexes = ['thread_id', 'resource_id'];

    await this.vector.createIndex(createParams);
    return { indexName };
  }

  public getMergedThreadConfig(config?: MemoryConfigInternal): MemoryConfigInternal {
    if (config?.workingMemory && typeof config.workingMemory === 'object' && 'use' in config.workingMemory) {
      throw new Error('The workingMemory.use option has been removed. Working memory always uses tool-call mode.');
    }

    if (config?.threads?.generateTitle !== undefined) {
      throw new Error(
        'The threads.generateTitle option has been moved. Use the top-level generateTitle option instead.',
      );
    }

    const mergedConfig = deepMerge(this.threadConfig, config || {});

    if (
      typeof config?.workingMemory === 'object' &&
      config.workingMemory?.schema &&
      typeof mergedConfig.workingMemory === 'object'
    ) {
      mergedConfig.workingMemory.schema = config.workingMemory.schema;
    }

View on GitHub (pinned to 75dd419e61)

Solutions

Delete the `use` property from the workingMemory object in your Memory options.
Keep other workingMemory settings (template, useStateSignals) that remain supported.
Search your codebase for 'use:' inside workingMemory config blocks after upgrading.

Example fix

// before
options: { workingMemory: { use: 'tool-call', template: 'User name: {{name}}' } }

// after
options: { workingMemory: { template: 'User name: {{name}}' } }

Defensive patterns

Strategy: validation

Validate before calling

function assertNoWorkingMemoryUse(options) {
  const wm = options?.workingMemory;
  if (wm && typeof wm === 'object' && 'use' in wm) throw new Error('Remove workingMemory.use; tool-call mode is always used');
}

Type guard

function isModernWorkingMemory(wm) {
  return wm === undefined || typeof wm === 'string' || (typeof wm === 'object' && wm !== null && !('use' in wm));
}

Prevention

After upgrading, grep for workingMemory blocks containing 'use:'.
Type Memory options with a type that omits `use` so TS catches it.
Keep memory options in a single typed constants file.

When it happens

Trigger: Passing options like { workingMemory: { use: 'tool-call', template: '...' } } into Memory options, thread config, or getMergedThreadConfig.

Common situations: Upgrading from an older Mastra version where workingMemory.use was valid; copy-pasting blog posts or old docs examples; generated config code still emitting the deprecated field.

Related errors

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/4c6eb251695a285c. Report an issue: GitHub.