Workflow Orchestrator MCP Server

Workflow Orchestrator MCP Server

This project implements an AI-Powered Workflow Orchestrator as an MCP (Model Context Protocol) server. It is designed to manage and execute complex, dynamic workflows by leveraging a Large Language Model (LLM) for intelligent decision-making and adaptability.

Core Concepts

The orchestrator breaks down complex tasks into manageable, discrete steps defined within workflows. An AI agent (LLM) determines the sequence of these steps dynamically based on:

• The workflow definition (written in Markdown).
• The current task context (state variables).
• Real-time feedback provided by the client executing the steps.

Key concepts include:

• AI-Driven Decisions: Enables dynamic branching, error handling, and adaptation based on step outcomes and context.
• Markdown Definitions: Workflows and steps are defined in human-readable Markdown files.
• Persistent State: Workflow state is stored in a local SQLite database, allowing for long-running processes.
• Workflow Resumption: Interrupted workflows can be resumed, with the AI helping reconcile the client's state with the persisted state.

Features

• Intelligent, Non-Linear Workflows: Moves beyond rigid scripts to adaptable processes.
• Reusable & Modular Steps: Step definitions in Markdown promote reuse and maintainability.
• Human-Readable & Editable: Easy to author and understand workflows.
• Adaptable Instructions & AI Prompts: Dynamically generated prompts provide rich context to the AI.
• Persistent State Management: Reliable tracking of workflow progress using SQLite.
• Resumption Capability: Recover and continue interrupted workflows seamlessly.

Architecture

The system uses a modular architecture:

graph LR
    Client --> A["API Layer (FastMCP)"];
    A --> B[Orchestration Engine];
    B --> C[Workflow Definition Service];
    B --> D[State Persistence Module];
    B --> E[AI Interaction Module];
    C --> F[(Workflow Files *.md)];
    D --> G[(SQLite Database)];
    E --> H[(External LLM Service)];

• API Layer (FastMCP Server): Handles MCP tool requests.
• Orchestration Engine: Core logic coordinating workflow execution.
• Workflow Definition Service: Loads, parses, and validates Markdown workflow definitions.
• State Persistence Module: Manages workflow state and history in the SQLite database (workflow_state.db).
• AI Interaction Module: Communicates with the external LLM service.

(See docs/architecture_and_data_model.md#2-high-level-architecture for full details).

Workflows

Workflows are defined in subdirectories within the WORKFLOW_DEFINITIONS_DIR directory specified in the MCP server settings. Each workflow has:

• index.md: Defines the overall goal and lists the steps.
• steps/: A directory containing individual Markdown files for each step, including # Orchestrator Guidance and # Client Instructions.

Available Workflows:

• ANALYZE_GITLAB_ISSUE
• COMMIT_SUGGESTER
• JOKE_GENERATOR
• README_FRESHNESS_CHECK
• REFACTOR_WITH_TESTS
• RESUME
• SAVE
• SUGGEST_REFACTORING
• WORKFLOW_CREATOR

(See docs/architecture_and_data_model.md#8-workflow-definition-service-details for more on the definition format).

MCP Tools

This server provides the following MCP tools:

• list_workflows: List available workflow definitions.
• start_workflow: Starts a workflow by name, optionally with initial context.
  • Input: { "workflow_name": "string", "context": {} }
• get_workflow_status: Gets the current status of a running workflow instance.
  • Input: { "instance_id": "string" }
• advance_workflow: Reports the outcome of the previous step and requests the next step.
  • Input: { "instance_id": "string", "report": { "step_id": "string", "result": any, "status": "string", ... }, "context_updates": {} }
• resume_workflow: Reconnects to an existing workflow instance, providing the client's assumed state for reconciliation.
  • Input: { "instance_id": "string", "assumed_current_step_name": "string", "report": { ... }, "context_updates": {} }

(Refer to the MCP server definition or docs/architecture_and_data_model.md#7-api-specification for detailed input/output schemas, noting the mapping from HTTP API to MCP tools).

Configuration

The server is configured via environment variables. Paths can be specified as relative to the current working directory or as absolute paths:

• WORKFLOW_DEFINITIONS_DIR (Required): Path to the workflow definitions directory (e.g., ./workflows or /home/user/projects/orchestrator-mcp-server/workflows).
• WORKFLOW_DB_PATH (Required): Path to the SQLite database file (e.g., ./data/workflows.sqlite or /home/user/projects/orchestrator-mcp-server/data/workflows.sqlite).
• GEMINI_MODEL_NAME (Required, unless USE_STUB_AI_CLIENT is true): The name of the Gemini model to use (e.g., gemini-2.5-flash-latest).
• USE_STUB_AI_CLIENT (Optional): Set to true to use a stubbed AI client for testing, bypassing the need for AI service configuration (default: false).
• LOG_LEVEL (Optional): Logging level (default: info).
• AI_SERVICE_ENDPOINT (Optional): URL for the LLM service API (only used if not using the stub client).
• AI_SERVICE_API_KEY (Optional): API key for the LLM service (only used if not using the stub client).
• AI_REQUEST_TIMEOUT_MS (Optional): Timeout for AI requests in milliseconds (default: 30000).

Quickstart / Running the Server

1. Prerequisites:
   • Python environment managed by uv.
   • Required environment variables set (see Configuration).
   • Ensure directories for WORKFLOW_DEFINITIONS_DIR and WORKFLOW_DB_PATH exist and are writable.
2. Install Dependencies:

   uv sync
   

3. Run the Server:

   uv run python -m orchestrator_mcp_server
   

   Alternatively, if you have installed the server using pipx install ., you can run the orchestrator-mcp-server command directly. By default, the server uses relative paths (./workflows and ./data/workflows.sqlite) for workflow definitions and the database. To use these default paths, you must run the orchestrator-mcp-server command from the project's root directory (/home/jean/git/orchestrator-mcp-server). If you set the WORKFLOW_DEFINITIONS_DIR and WORKFLOW_DB_PATH environment variables to absolute paths (see Configuration), you can run the orchestrator-mcp-server command from any directory.

Running with Cline

To run the orchestrator as an MCP server within Cline, add the following configuration to the mcpServers content of your cline_mcp_settings.json file:

"orchestrator-mcp-server": {
      "autoApprove": [],
      "disabled": false,
      "timeout": 60,
      "command": "orchestrator-mcp-server",
      "env": {
        "WORKFLOW_DEFINITIONS_DIR": "/home/YOUR_USERNAME/git/orchestrator-mcp-server/workflows",
        "WORKFLOW_DB_PATH": "/home/YOUR_USERNAME/git/orchestrator-mcp-server/workflow_state.db",
        "GEMINI_MODEL_NAME": "gemini-2.5-flash-preview-04-17",
        "GEMINI_API_KEY": "YOUR__API_KEY"
      },
      "transportType": "stdio"
    }

Remember to replace "YOUR_USERNAME" with your actual username and "YOUR_ANONYMIZED_API_KEY" with your actual Gemini API key and adjust the paths if your project is located elsewhere.

Development Status

Next Steps:

• Implement comprehensive integration tests to verify the system's behavior under various conditions.
• Continue refining error handling and edge cases.
• Expand documentation with usage examples and best practices.
• Develop additional workflow templates for common use cases.

Testing

The primary testing strategy involves integration tests exercising the API and core components, using a stubbed AI Interaction Module to provide deterministic responses. A dedicated test database is used. Unit tests cover specific utility functions and parsing logic.

(See docs/architecture_and_data_model.md#12-testing-strategy for details).