feat: add Crush harness support

[neiii]

Summary

• Add Crush harness support (profiles, CLI/TUI, MCP + skills install paths).
• Add Crush MCP read/write via crush.json with top-level mcp key.
• Add automated tests + README updates.

Dependency

Depends on neiii/harness-barn#7 (using edlsh/harness-barn branch feat/add-crush-harness until merged).

Testing

• cargo fmt -- --check
• cargo clippy -- -D warnings
• cargo test

[neiii]

@greptile

[greptile-apps]

Greptile Overview

Greptile Summary

Adds comprehensive Crush harness support to Bridle, enabling profile management, MCP installation, and skills integration for the Crush AI coding assistant.

Key Changes:

• Added Crush harness recognition across all CLI, TUI, and installation modules
• Implemented crush.json MCP configuration with top-level "mcp" key (similar to OpenCode)
• Added model extraction supporting both simple "model" key and nested "models.large.model" / "models.small.model" paths
• Included comprehensive test coverage for MCP read/write and profile operations
• Improved test isolation in config/manager/mod.rs by replacing unsafe env var manipulation with proper mutex-based locking
• Temporarily using git dependencies from edlsh/harness-barn branch until upstream PR merges

Implementation Quality:

• Consistent pattern matching across all modules (CLI, installer, uninstaller, TUI, etc.)
• Proper JSON handling (not JSONC) for Crush config files
• Good test coverage including integration tests for profile creation and MCP installation

Confidence Score: 4/5

• Safe to merge with minor enhancement opportunity for MCP extraction
• Implementation is thorough and consistent across all modules with good test coverage. The missing Crush-specific MCP extractor means detailed server info won't display in profile views (falls back to generic extraction), but this doesn't affect functionality - only UI completeness. Test isolation improvements are solid. Dependency on feature branch is temporary and documented.
• Check src/config/manager/extraction/mod.rs for the optional MCP extraction enhancement

Important Files Changed

File Analysis

Filename	Score	Overview
src/config/manager/extraction/mod.rs	4/5	Added extract_model_crush() for model extraction, but missing extract_mcp_from_crush_config() - Crush falls back to generic MCP extraction which loses detailed server info
src/install/mcp_config.rs	5/5	Added Crush support with "mcp" key correctly, consistent with OpenCode pattern, handles JSON (not JSONC)
src/install/mcp_installer.rs	5/5	Added Crush harness parsing and config path mapping, includes comprehensive test coverage
tests/mcp_installation.rs	5/5	Added test for Crush JSON read/write operations with MCP config, validates schema and structure
tests/cli_integration.rs	5/5	Added comprehensive Crush profile tests covering model extraction and profile creation from current config
src/config/manager/mod.rs	5/5	Improved test isolation by replacing unsafe env var manipulation with proper mutex-based locking
Cargo.toml	4/5	Switched to git dependencies from edlsh/harness-barn feat branch (temporary until upstream merge)

Sequence Diagram

sequenceDiagram
    participant User
    participant CLI
    participant ProfileMgr as Profile Manager
    participant McpInstaller as MCP Installer
    participant McpConfig as MCP Config
    participant CrushFS as Crush Filesystem

    Note over User,CrushFS: Crush Harness Installation Flow

    User->>CLI: bridle install owner/repo crush my-profile
    CLI->>ProfileMgr: resolve_harness("crush")
    ProfileMgr-->>CLI: HarnessKind::Crush
    
    CLI->>McpInstaller: install_mcp(name, server, target)
    McpInstaller->>McpInstaller: parse_harness_kind("crush")
    McpInstaller->>McpInstaller: get_profile_config_path(Crush)
    Note right of McpInstaller: Returns profile_dir/crush.json
    
    McpInstaller->>McpConfig: read_mcp_config(Crush, path)
    McpConfig->>McpConfig: get_mcp_key(Crush)
    Note right of McpConfig: Returns "mcp" key
    McpConfig->>CrushFS: read crush.json
    CrushFS-->>McpConfig: JSON content
    McpConfig->>McpConfig: Parse JSON & extract "mcp" section
    McpConfig-->>McpInstaller: Existing MCP servers map
    
    McpInstaller->>McpConfig: write_mcp_config(Crush, path, servers)
    McpConfig->>CrushFS: Read existing crush.json
    CrushFS-->>McpConfig: Current config
    McpConfig->>McpConfig: Merge new MCP into "mcp" key
    McpConfig->>CrushFS: Write updated crush.json
    CrushFS-->>McpConfig: Success
    McpConfig-->>McpInstaller: Success
    McpInstaller-->>CLI: McpInstallOutcome::Installed
    CLI-->>User: Installation successful

    Note over User,CrushFS: Profile Switch Flow

    User->>CLI: bridle profile switch crush my-profile
    CLI->>ProfileMgr: switch_profile(crush, my-profile)
    ProfileMgr->>CrushFS: Copy profile/crush/my-profile/* to ~/.config/crush/
    Note right of ProfileMgr: Includes crush.json with MCP config
    ProfileMgr-->>CLI: Success
    CLI-->>User: Profile switched

    Note over User,CrushFS: Model Extraction Flow

    User->>CLI: bridle profile show crush my-profile
    CLI->>ProfileMgr: extract_model(crush_harness, profile_path)
    ProfileMgr->>ProfileMgr: extract_model_crush(profile_path)
    ProfileMgr->>CrushFS: Read crush.json
    CrushFS-->>ProfileMgr: JSON content
    ProfileMgr->>ProfileMgr: Try "model" key
    alt model key exists
        ProfileMgr-->>CLI: model value
    else check models.large
        ProfileMgr->>ProfileMgr: Try "models.large.model"
        ProfileMgr-->>CLI: large model value
    else check models.small
        ProfileMgr->>ProfileMgr: Try "models.small.model"
        ProfileMgr-->>CLI: small model value
    end
    CLI-->>User: Display model info

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[greptile-apps]

Additional Comments (1)

src/config/manager/extraction/mod.rs
Missing "crush" case - falls back to extract_mcp_generic() which only extracts server names, not detailed info (type, command, args, url). Consider adding:

    match harness.id() {
        "opencode" => extract_mcp_from_opencode_config(profile_path),
        "crush" => extract_mcp_from_crush_config(profile_path),
        "amp-code" => extract_mcp_from_ampcode_config(profile_path),
        "claude-code" => extract_mcp_from_claudecode_config(profile_path),
        "goose" => extract_mcp_from_goose_config(profile_path),
        _ => extract_mcp_generic(harness, profile_path),
    }

Then implement extract_mcp_from_crush_config() similar to extract_mcp_from_opencode_config() (lines 11-55) but reading crush.json instead of opencode.jsonc.

Prompt To Fix With AI

This is a comment left during a code review.
Path: src/config/manager/extraction/mod.rs
Line: 61:67

Comment:
Missing `"crush"` case - falls back to `extract_mcp_generic()` which only extracts server names, not detailed info (type, command, args, url). Consider adding:

```suggestion
    match harness.id() {
        "opencode" => extract_mcp_from_opencode_config(profile_path),
        "crush" => extract_mcp_from_crush_config(profile_path),
        "amp-code" => extract_mcp_from_ampcode_config(profile_path),
        "claude-code" => extract_mcp_from_claudecode_config(profile_path),
        "goose" => extract_mcp_from_goose_config(profile_path),
        _ => extract_mcp_generic(harness, profile_path),
    }
```

Then implement `extract_mcp_from_crush_config()` similar to `extract_mcp_from_opencode_config()` (lines 11-55) but reading `crush.json` instead of `opencode.jsonc`.

How can I resolve this? If you propose a fix, please make it concise.