graph TD
    Client["MCP Clients<br/>(Claude Desktop / Claude Code / Cursor / Windsurf)"]
    Server["ellmos CodeCommander MCP Server<br/>(stdio transport • Node.js)"]

    subgraph Tools["Developer Tool Suites (23 Tools)"]
        subgraph CodeIntel["Code & Python Intelligence"]
            C1["cc_analyze_code"]
            C2["cc_analyze_methods"]
            C3["cc_extract_classes"]
            C4["cc_check_indentation"]
            C5["cc_generate_python_code"]
            C6["cc_python_structural_edit"]
        end

        subgraph Imports["Import Management"]
            I1["cc_organize_imports"]
            I2["cc_diagnose_imports"]
            I3["cc_runtime_import_diagnose"]
        end

        subgraph Repair["Text, JSON & Encoding Repair"]
            R1["cc_fix_json"]
            R2["cc_validate_json"]
            R3["cc_fix_encoding"]
            R4["cc_cleanup_file"]
            R5["cc_fix_umlauts"]
        end

        subgraph Utility["Utilities & Conversion"]
            U1["cc_convert_format (JSON/CSV/YAML/TOML/XML/TOON)"]
            U2["cc_diff_files (Unified Diff)"]
            U3["cc_regex_test (Regex Tester)"]
            U4["cc_scan_emoji"]
            U5["cc_generate_licenses"]
        end

        subgraph Export["Export & i18n"]
            E1["cc_md_to_html"]
            E2["cc_md_to_pdf"]
            E3["cc_set_language"]
            E4["cc_get_language"]
        end
    end

    Client -->|Stdio JSON-RPC| Server
    Server --> CodeIntel
    Server --> Imports
    Server --> Repair
    Server --> Utility
    Server --> Export

sequenceDiagram
    autonumber
    actor Developer as Developer / LLM Client
    participant Stdio as CodeCommander Server (stdio)
    participant Core as AST & Code Intelligence Core
    participant Disk as Local Filesystem

    Developer->>Stdio: cc_python_structural_edit (mode: "preview" / "apply")
    Stdio->>Core: Parse Python AST & Validate Syntax
    alt Validation Failed
        Core-->>Stdio: Syntax / Parsing Diagnostics
        Stdio-->>Developer: Error Diagnostics & Line References
    else Validation Passed
        Core->>Disk: Read Original File
        Core->>Core: Compute Unified Structural Diff
        alt Mode == "preview"
            Core-->>Stdio: Return Diff Preview (Zero File Mutations)
            Stdio-->>Developer: Structural Diff Preview
        else Mode == "apply"
            Core->>Disk: Create .bak Backup File
            Core->>Disk: Write Modified AST Code In-Place
            Core-->>Stdio: Confirmation with Applied Diff & Backup Path
            Stdio-->>Developer: Success Payload
        end
    end