sequenceDiagram
participant Client as MCP Client
participant Server as Gmail MCP Server
participant JobQueue as Job Queue
participant LocalCacheDB as LocalCacheDB (SQLite)
participant JobStatusStore as Job Status Store
participant CategorizationWorker as Categorization Worker
Client->>Server: Call tool categorize_emails(params)
Server->>JobStatusStore: createJob(job_type, request_params)
JobStatusStore->>LocalCacheDB: INSERT INTO job_statuses (PENDING)
LocalCacheDB-->>JobStatusStore: job_id
JobStatusStore-->>Server: job_id (J123)
Server->>JobQueue: Add job_id (J123) to queue
JobQueue-->>Server: Job added acknowledgment
Server-->>Client: Job Accepted (Job ID: J123)
loop Client Polling for Status
Client->>Server: Call tool get_job_status(J123)
Server->>JobStatusStore: getJobStatus(J123)
JobStatusStore->>LocalCacheDB: SELECT * FROM job_statuses WHERE job_id='J123'
LocalCacheDB-->>JobStatusStore: Job Record (status, progress, results, error_details)
alt Job status is COMPLETED or FAILED
JobStatusStore-->>Server: Final Job Status and Results or Errors
Server-->>Client: Final Job Status and Results or Errors
else Job status is PENDING or IN_PROGRESS
JobStatusStore-->>Server: Current Job Status and Progress
Server-->>Client: Current Job Status and Progress
end
end
CategorizationWorker->>JobQueue: Retrieve job_id (J123)
JobQueue-->>CategorizationWorker: job_id (J123)
CategorizationWorker->>JobStatusStore: updateJobStatus(J123, IN_PROGRESS, started_at)
JobStatusStore->>LocalCacheDB: UPDATE job_statuses SET status='IN_PROGRESS', started_at=...
LocalCacheDB-->>JobStatusStore: Update Acknowledged
CategorizationWorker->>CategorizationWorker: Perform Categorization Logic (long-running task)
alt Categorization completes successfully
CategorizationWorker->>JobStatusStore: updateJobStatus(J123, COMPLETED, completed_at, results)
JobStatusStore->>LocalCacheDB: UPDATE job_statuses SET status='COMPLETED', completed_at=..., results=...
LocalCacheDB-->>JobStatusStore: Update Acknowledged
else Categorization fails
CategorizationWorker->>JobStatusStore: updateJobStatus(J123, FAILED, completed_at, error_details)
JobStatusStore->>LocalCacheDB: UPDATE job_statuses SET status='FAILED', completed_at=..., error_details=...
LocalCacheDB-->>JobStatusStore: Update Acknowledged
end
