mastra-ai/mastra · error · Error

Agent with id ${id} not found

Error message

Agent with id ${id} not found

What it means

`update` looks up the agent by `id` in the in-memory map and throws when no row exists. Updates never create agents implicitly.

Source

Thrown at packages/core/src/storage/domains/agents/inmemory.ts:92

    await this.createVersion({
      id: versionId,
      agentId: agent.id,
      versionNumber: 1,
      ...snapshotConfig,
      changedFields: Object.keys(snapshotConfig),
      changeMessage: 'Initial version',
    });

    // Return the thin agent record (activeVersionId remains null)
    return this.deepCopyAgent(newAgent);
  }

  async update(input: StorageUpdateAgentInput): Promise<StorageAgentType> {
    const { id, ...updates } = input;

    const existingAgent = this.db.agents.get(id);
    if (!existingAgent) {
      throw new Error(`Agent with id ${id} not found`);
    }

    const { authorId, visibility, activeVersionId, metadata, status } = updates;

    const updatedAgent: StorageAgentType = {
      ...existingAgent,
      ...(authorId !== undefined && { authorId }),
      ...(visibility !== undefined && { visibility }),
      ...(activeVersionId !== undefined && { activeVersionId }),
      ...(metadata !== undefined && {
        metadata: { ...existingAgent.metadata, ...metadata },
      }),
      ...(status !== undefined && { status }),
      updatedAt: new Date(),
    };

    this.db.agents.set(id, updatedAgent);
    return this.deepCopyAgent(updatedAgent);

View on GitHub (pinned to 75dd419e61)

Solutions

1. Verify the agent exists (get by ID) before updating, or create it if missing
2. Ensure you are using the same store instance that holds the agent (in-memory data does not survive restarts)
3. Log/validate the incoming `id` — check for typos or IDs from another environment

Example fix

// before
await agents.update({ id: 'agent-1', name: 'new-name' });
// after
if (await agents.get({ agentId: 'agent-1' })) {
  await agents.update({ id: 'agent-1', name: 'new-name' });
}

const existing = await agentsDomain.get({ agentId: id });
if (!existing) {
  // create the agent first or surface a 404 to the caller
}

null

try {
  await agentsDomain.update({ id, ...updates });
} catch (e) {
  if (e instanceof Error && /Agent with id .* not found/.test(e.message)) {
    throw new NotFoundError(`Agent ${id} does not exist in this store`);
  }
  throw e;
}

When it happens

Trigger: Calling `update({ id, ... })` with an ID that was never created, was created in a different store instance, or belongs to an in-memory store that was reset (process restart loses all data).

Common situations: Updating an agent after a dev-server restart wiped the in-memory DB; using an ID from a different environment/store; race where another caller deleted the agent first; typo in the agent ID.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• Dataset not found: ${args.id}
• Dataset not found: ${args.datasetId}
• Item not found: ${args.id}
• MCP client with id ${id} not found
• MCP server with id ${id} not found

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/3967f301f84acae4. Report an issue: GitHub.