Cascaded Reasoning with Adaptive Step Handling

a.k.a CRASH

"Use crash to ..."

An advanced MCP (Model Context Protocol) server that facilitates structured, iterative reasoning for complex problem-solving and analysis. CRASH v2.0 introduces flexible validation, confidence tracking, revision mechanisms, and branching support while maintaining backward compatibility.

Heavily inspired by MCP Sequential Thinking Server

Why I made this?

Frankly, I created this because typing "use sequential_thinking" was cumbersome. Now I can simply say "use crash" instead!

That was just the starting point though. CRASH is a modified version of sequential thinking with token-efficiency as its core design principle. It's more streamlined in its prompting approach - it doesn't include codes in thoughts and doesn't require the agent to list all available tools, etc.

I've had great experience with CRASH so far and have completely replaced sequential thinking in my workflow. It's now my go-to solution whenever an agent can't solve an issue in one shot or even when plan mode falls short.

Claude Code's Experience

## Question
> /ask is running… Did the CRASH-MCP actually help you, or would you have been better off using your internal planning mechanisms?

● CRASH MCP helped significantly for this specific task. Here's my honest assessment:

Where CRASH helped:
- Systematic analysis: It forced me to break down the GitHub issue methodically, understanding the exact problem before jumping to solutions
- Solution exploration: I explored multiple approaches (preprocessing, decorators, direct modification) before settling on the best one
- Planning validation: Each step built on the previous one logically, ensuring I didn't miss critical aspects

Where my internal planning would have been sufficient:
- Implementation execution: Once I had the plan, the actual coding was straightforward - I could have done that without CRASH
- Code pattern recognition: I could have immediately recognized this as a parameter serialization issue

The key difference:
CRASH forced me to be more thorough in the analysis phase. Without it, I might have rushed to implement the first solution that came to mind (like using Union[str, dict] parameters) rather than exploring the cleaner parse_tool_input() helper approach.

Verdict: CRASH added value here because this was a complex problem requiring systematic analysis of multiple solution paths. For simpler coding tasks, my internal planning would be sufficient and faster.

🚀 Key Features

Core Capabilities

• 🎯 Flexible Purpose Types: Extended set including validation, exploration, hypothesis, correction, planning, plus custom purposes
• 📝 Natural Language Flow: No forced prefixes or rigid formatting (configurable)
• 🔄 Revision Mechanism: Correct and improve previous reasoning steps
• 🌿 Branching Support: Explore multiple solution paths in parallel
• 📊 Confidence Tracking: Express uncertainty with confidence scores (0-1 scale)
• 🔧 Structured Actions: Enhanced tool integration with parameters and expected outputs
• 💾 Session Management: Multiple concurrent reasoning chains with unique IDs
• 📋 Multiple Output Formats: Console, JSON, and Markdown formatting

Configuration Options

• Strict Mode: Legacy compatibility with original rigid validation
• Flexible Mode: Full access to enhanced features (default)
• Customizable Validation: Toggle prefix requirements independently
• Environment Variables: Easy configuration without code changes

📦 Installation

npm install crash-mcp

Or use directly with npx:

npx crash-mcp

Requirements

• Node.js >= v18.0.0
• Cursor, Claude Code, VSCode, Windsurf or another MCP Client

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "crash-mcp"],
      "env": {
        "MAX_HISTORY_SIZE": "100",
        "CRASH_STRICT_MODE": "false",
        "CRASH_OUTPUT_FORMAT": "console",
        "CRASH_NO_COLOR": "false"
      }
    }
  }
}

claude mcp add crash -- npx -y crash-mcp

claude mcp add crash '--' npx -y crash-mcp

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "crash-mcp"],
      "env": {
        "MAX_HISTORY_SIZE": "100",
        "CRASH_STRICT_MODE": "false",
        "CRASH_OUTPUT_FORMAT": "console"
      }
    }
  }
}

"mcp": {
  "servers": {
    "crash": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "crash-mcp"],
      "env": {
        "CRASH_STRICT_MODE": "false",
        "MAX_HISTORY_SIZE": "100"
      }
    }
  }
}

{
  "context_servers": {
    "CRASH": {
      "command": {
        "path": "npx",
        "args": ["-y", "crash-mcp"]
      },
      "settings": {
        "env": {
          "CRASH_STRICT_MODE": "false",
          "MAX_HISTORY_SIZE": "100"
        }
      }
    }
  }
}

"augment.advanced": {
  "mcpServers": [
    {
      "name": "crash",
      "command": "npx",
      "args": ["-y", "crash-mcp"]
    }
  ]
}

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "crash-mcp"],
      "env": {
        "MAX_HISTORY_SIZE": "100",
        "CRASH_STRICT_MODE": "false",
        "CRASH_OUTPUT_FORMAT": "console",
        "CRASH_NO_COLOR": "false"
      }
    }
  }
}

{
  "mcp": {
    "crash": {
      "type": "local",
      "command": ["npx", "-y", "crash-mcp"],
      "enabled": true
    }
  }
}

[mcp_servers.crash]
args = ["-y", "crash-mcp"]
command = "npx"

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

{
  "mcpServers": {
    "CRASH": {
      "command": "npx",
      "args": ["-y", "crash-mcp"],
      "env": {},
      "disabled": false,
      "autoApprove": []
    }
  }
}

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

{
  "mcpServers": {
    "crash": {
      "command": "bunx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

{
  "mcpServers": {
    "crash": {
      "command": "deno",
      "args": [
        "run",
        "--allow-env=NO_DEPRECATION,TRACE_DEPRECATION,MAX_HISTORY_SIZE,CRASH_STRICT_MODE,CRASH_OUTPUT_FORMAT,CRASH_NO_COLOR",
        "--allow-net",
        "npm:crash-mcp"
      ]
    }
  }
}

{
  "mcpServers": {
    "crash": {
      "command": "cmd",
      "args": ["/c", "npx", "-y", "crash-mcp"],
      "disabled": false,
      "autoApprove": []
    }
  }
}

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

{
  "CRASH": {
    "command": "npx",
    "args": ["-y", "crash-mcp"],
    "env": {
      "CRASH_STRICT_MODE": "false",
      "MAX_HISTORY_SIZE": "100"
    },
    "working_directory": null,
    "start_on_launch": true
  }
}

{
  "mcpServers": {
    "CRASH": {
      "command": "npx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

{
  "mcp": {
    "servers": {
      "crash": {
        "type": "stdio",
        "command": "npx",
        "args": ["-y", "crash-mcp"]
      }
    }
  }
}

{
  "$schema": "https://charm.land/crush.json",
  "mcp": {
    "crash": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

acli rovodev mcp

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

{
  "command": "npx",
  "args": ["-y", "crash-mcp"]
}

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

{
  "args": ["-y", "crash-mcp"],
  "command": "npx",
  "env": {
    "CRASH_STRICT_MODE": "false",
    "MAX_HISTORY_SIZE": "100"
  }
}

⚙️ Configuration

Environment Variables

🛠️ Tool Usage

Basic Parameters (Required)

• step_number: Sequential step number
• estimated_total: Current estimate of total steps (adjustable)
• purpose: Step purpose (see Purpose Types below)
• context: What is already known to avoid redundancy
• thought: Current reasoning (natural language)
• outcome: Expected/actual result
• next_action: Next tool or action (string or structured object)
• rationale: Why this action is chosen

Enhanced Parameters (Optional)

Confidence & Uncertainty

• confidence: 0-1 scale confidence level
• uncertainty_notes: Describe doubts or concerns

Revision Support

• revises_step: Step number to revise
• revision_reason: Why revision is needed

Branching

• branch_from: Step to branch from
• branch_id: Unique branch identifier
• branch_name: Descriptive branch name

Tool Integration

• tools_used: Array of tools used
• external_context: External data/outputs
• dependencies: Step numbers this depends on

Session Management

• session_id: Group related reasoning chains

📝 Purpose Types

Standard Purposes

• analysis - Analyzing information
• action - Taking an action
• reflection - Reflecting on progress
• decision - Making a decision
• summary - Summarizing findings
• validation - Validating results
• exploration - Exploring options
• hypothesis - Forming hypotheses
• correction - Correcting errors
• planning - Planning approach

Custom Purposes

When not in strict mode, any string can be used as a purpose.

💡 Examples

Basic Usage

{
  "step_number": 1,
  "estimated_total": 3,
  "purpose": "analysis",
  "context": "User requested optimization of database queries",
  "thought": "I need to first understand the current query patterns",
  "outcome": "Identified slow queries for optimization",
  "next_action": "analyze query execution plans",
  "rationale": "Understanding execution plans will reveal bottlenecks"
}

With Confidence Tracking

{
  "step_number": 2,
  "estimated_total": 5,
  "purpose": "hypothesis",
  "context": "Slow queries identified, need optimization strategy",
  "thought": "The main issue appears to be missing indexes",
  "outcome": "Hypothesis about missing indexes formed",
  "next_action": "validate hypothesis with EXPLAIN",
  "rationale": "Need to confirm before making changes",
  "confidence": 0.7,
  "uncertainty_notes": "Could also be due to table statistics"
}

Revision Example

{
  "step_number": 4,
  "estimated_total": 5,
  "purpose": "correction",
  "context": "Previous analysis was incomplete",
  "thought": "I missed an important join condition",
  "outcome": "Corrected analysis with complete information",
  "next_action": "re-evaluate optimization strategy",
  "rationale": "New information changes the approach",
  "revises_step": 2,
  "revision_reason": "Overlooked critical join in initial analysis"
}

Branching Example

{
  "step_number": 3,
  "estimated_total": 6,
  "purpose": "exploration",
  "context": "Two possible optimization approaches identified",
  "thought": "Let me explore the indexing approach first",
  "outcome": "Branch created for index optimization",
  "next_action": "test index performance",
  "rationale": "This approach has lower risk",
  "branch_from": 2,
  "branch_id": "index-optimization",
  "branch_name": "Index-based optimization"
}

Structured Action Example

{
  "step_number": 5,
  "estimated_total": 7,
  "purpose": "action",
  "context": "Ready to implement optimization",
  "thought": "Implementing the index creation",
  "outcome": "Index created successfully",
  "next_action": {
    "tool": "sql_executor",
    "action": "CREATE INDEX",
    "parameters": {
      "table": "users",
      "columns": ["email", "created_at"]
    },
    "expectedOutput": "Index created on users table"
  },
  "rationale": "This index will optimize the most common query pattern",
  "tools_used": ["sql_executor"],
  "confidence": 0.9
}

🔄 Backward Compatibility

Strict Mode

Enable strict mode for legacy behavior:

export CRASH_STRICT_MODE=true

In strict mode: - Thoughts must start with required prefixes - Rationale must start with "To " - Only predefined purpose types allowed - Original validation rules enforced

🏗️ Development

# Install dependencies
npm install

# Build TypeScript
npm run build

# Run in development mode
npm run dev

# Start built server
npm start

🚨 Troubleshooting

{
  "mcpServers": {
    "crash": {
      "command": "bunx",
      "args": ["-y", "crash-mcp"]
    }
  }
}

{
  "mcpServers": {
    "crash": {
      "command": "npx",
      "args": ["-y", "--node-options=--experimental-vm-modules", "crash-mcp"]
    }
  }
}

🎯 Use Cases

When to Use CRASH

1. Complex Problem Solving: Multi-step tasks requiring systematic approach
2. Code Analysis & Optimization: Understanding and improving codebases
3. System Design: Planning architecture with multiple considerations
4. Debugging: Systematic error investigation with hypothesis testing
5. Research & Exploration: Investigating multiple solution paths
6. Decision Making: Evaluating options with confidence tracking

When NOT to Use CRASH

1. Simple, single-step tasks: Direct action is more efficient
2. Pure information retrieval: No reasoning required
3. Time-critical operations: Overhead of structured reasoning
4. Deterministic procedures: No uncertainty or exploration needed

🔍 Comparison with Sequential Thinking

📊 Performance

• Memory: Configurable history size prevents unbounded growth
• Processing: Minimal overhead (~1-2ms per step)
• Token Usage: Optimized prompts, no code generation in thoughts
• Scalability: Session management for concurrent chains

🎯 Credits & Inspiration

CRASH is an adaptation and enhancement of the sequential thinking tools from the Model Context Protocol ecosystem:

• Primary Source: MCP Sequential Thinking Server - Official MCP implementation
• Secondary Inspiration: MCP Sequential Thinking Tools - Community adaptation

CRASH builds upon these foundations by adding flexible validation, confidence tracking, revision mechanisms, branching support, and enhanced tool integration while maintaining the core structured reasoning approach.

👨‍💻 Author

Nikko Gonzales - Email: nikkoxgonzales@gmail.com - GitHub: nikkoxgonzales

🤝 Contributing

Contributions welcome! Areas for enhancement:

1. Visualization: Graph/tree view for branches
2. Persistence: Save/load reasoning sessions
3. Analytics: Pattern recognition in reasoning
4. Integration: More MCP tool integrations
5. Templates: Pre-built reasoning templates

📄 License

MIT

🔗 Links

• MCP Protocol Specification
• Original Sequential Thinking Server
• Community Sequential Thinking Tools

📈 Version History

v2.0.0 (Current)

• Flexible validation system
• Confidence tracking
• Revision mechanism
• Branching support
• Structured actions
• Multiple output formats
• Session management
• Backward compatibility

v1.0.0

• Initial release
• Basic structured reasoning
• Required prefixes
• Five purpose types
• Console output only