mastra-ai/mastra · error · Error

The threads.generateTitle option has been moved. Use the top

Error message

The threads.generateTitle option has been moved. Use the top-level generateTitle option instead.

What it means

The threads.generateTitle option was relocated to a top-level generateTitle option in Memory config. getMergedThreadConfig throws this Error when a config still nests generateTitle under threads, preventing silent misconfiguration after the API move.

Source

Thrown at packages/core/src/memory/memory.ts:388

      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;
    }

    return mergedConfig;
  }

  estimateTokens(text: string): number {

View on GitHub (pinned to 75dd419e61)

Solutions

Move generateTitle from threads to the top level of your memory options.
Search configs for 'threads' blocks containing generateTitle after upgrading.
Consult current Mastra memory docs for the new generateTitle placement.

Example fix

// before
options: { threads: { generateTitle: true } }

// after
options: { generateTitle: true }

Defensive patterns

Strategy: validation

Validate before calling

function assertNoNestedGenerateTitle(options) {
  if (options?.threads && 'generateTitle' in options.threads) {
    throw new Error('Move threads.generateTitle to top-level generateTitle');
  }
}

Type guard

function usesMovedGenerateTitle(cfg) {
  return !!cfg?.threads && 'generateTitle' in cfg.threads;
}

Prevention

After upgrades, grep for threads: { generateTitle.
Rely on TypeScript exhaustively typed Memory options to flag unknown nested fields.
Follow current Mastra memory migration notes when bumping major versions.

When it happens

Trigger: Passing { threads: { generateTitle: true } } in Memory options or any config passed to getMergedThreadConfig.

Common situations: Upgrading across a Mastra version where generateTitle moved; following older documentation or tutorials; code generators emitting the old nested shape.

Related errors

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/df18707e97cb5c39. Report an issue: GitHub.