What can you do with this server?

The CRASH server enables structured, iterative reasoning for complex problem-solving and analysis by breaking down tasks into sequential steps with defined purposes (analysis, action, validation, planning, etc.). Key capabilities include: • **Confidence tracking** with 0-1 scale uncertainty measurement and doubt documentation • **Revision mechanism** to correct and improve previous steps with documented rationale • **Branching support** for exploring multiple solution paths concurrently using unique IDs • **Tool integration** with structured actions, parameters, and expected outputs • **Session management** for handling multiple concurrent reasoning chains • **Flexible output formats** (console, JSON, Markdown) with configurable settings • **Context awareness** to track completed steps and avoid redundancy • **Custom purposes** beyond standard step types for extended functionality Ideal for code analysis, system design, debugging, research, decision-making, and comprehensive solution exploration.

Which integrations are available for this server?

Provides [Markdown](/mcp/servers/integrations/markdown) output formatting for human-readable documentation of reasoning processes and analysis workflows Distributed as an [npm](/mcp/servers/integrations/npm) package for easy installation and integration into Node.js-based MCP server environments Built with [TypeScript](/mcp/servers/integrations/typescript) for type-safe development and enhanced tooling support in the reasoning server implementation

CRASH

Cascaded Reasoning with Adaptive Step Handling

An MCP (Model Context Protocol) server for structured, iterative reasoning. CRASH helps AI assistants break down complex problems into trackable steps with confidence tracking, revision support, and branching for exploring alternatives.

Inspired by MCP Sequential Thinking Server

Related MCP server: Sequential Thinking MCP Server

Why CRASH?

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

CRASH is more token-efficient than sequential thinking - it doesn't include code in thoughts and has streamlined prompting. It's my go-to solution when an agent can't solve an issue in one shot or when plan mode falls short.

Claude Code's Assessment

CRASH helped significantly for this specific task: Where CRASH helped: - Systematic analysis: Forced me to break down the issue methodically - Solution exploration: Explored multiple approaches before settling on the best one - Planning validation: Each step built on the previous one logically 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 rather than exploring cleaner approaches. Verdict: CRASH adds value for complex problems requiring systematic analysis of multiple solution paths. For simpler tasks, internal planning is sufficient and faster.

Features

Structured reasoning steps - Track thought process, outcomes, and next actions
Confidence tracking - Express uncertainty with 0-1 scores, get warnings on low confidence
Revision mechanism - Correct previous steps, with original steps marked as revised
Branching support - Explore multiple solution paths with depth limits
Dependency validation - Declare and validate step dependencies
Session management - Group related reasoning chains with automatic timeout cleanup
Multiple output formats - Console (colored), JSON, or Markdown
Flexible validation - Strict mode for rigid rules, flexible mode for natural language

Installation

npm install crash-mcp

Or use directly with npx:

npx crash-mcp

Quick Setup

Most MCP clients use this JSON configuration:

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

Configuration by Client

Client	Setup Method
Claude Code	`claude mcp add crash -- npx -y crash-mcp`
Cursor	Add to `~/.cursor/mcp.json`
VS Code	Add to settings JSON under `mcp.servers`
Claude Desktop	Add to `claude_desktop_config.json`
Windsurf	Add to MCP config file
JetBrains	Settings > Tools > AI Assistant > MCP
Others	Use standard MCP JSON config above

Use the cmd wrapper:

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

{ "mcpServers": { "crash": { "command": "npx", "args": ["-y", "crash-mcp"], "env": { "CRASH_STRICT_MODE": "false", "MAX_HISTORY_SIZE": "100", "CRASH_OUTPUT_FORMAT": "console", "CRASH_SESSION_TIMEOUT": "60", "CRASH_MAX_BRANCH_DEPTH": "5" } } } }

FROM node:18-alpine WORKDIR /app RUN npm install -g crash-mcp CMD ["crash-mcp"]

{ "mcpServers": { "crash": { "command": "docker", "args": ["run", "-i", "--rm", "crash-mcp"] } } }

Bun:

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

Deno:

{ "command": "deno", "args": ["run", "--allow-env", "--allow-net", "npm:crash-mcp"] }

Configuration

Variable	Default	Description
`CRASH_STRICT_MODE`	`false`	Enable strict validation (requires specific prefixes)
`MAX_HISTORY_SIZE`	`100`	Maximum steps to retain in history
`CRASH_OUTPUT_FORMAT`	`console`	Output format: `console` , `json` , `markdown`
`CRASH_NO_COLOR`	`false`	Disable colored console output
`CRASH_SESSION_TIMEOUT`	`60`	Session timeout in minutes
`CRASH_MAX_BRANCH_DEPTH`	`5`	Maximum branch nesting depth
`CRASH_ENABLE_SESSIONS`	`false`	Enable session management

Usage

Required Parameters

Parameter	Type	Description
`step_number`	integer	Sequential step number (starts at 1)
`estimated_total`	integer	Estimated total steps (adjustable)
`purpose`	string	Step category: analysis, action, validation, exploration, hypothesis, correction, planning, or custom
`context`	string	What's already known to avoid redundancy
`thought`	string	Current reasoning process
`outcome`	string	Expected or actual result
`next_action`	string/object	Next action (simple string or structured with tool details)
`rationale`	string	Why this next action was chosen

Optional Parameters

Parameter	Type	Description
`is_final_step`	boolean	Mark as final step to complete reasoning
`confidence`	number	Confidence level 0-1 (warnings below 0.5)
`uncertainty_notes`	string	Describe doubts or assumptions
`revises_step`	integer	Step number being corrected
`revision_reason`	string	Why revision is needed
`branch_from`	integer	Step to branch from
`branch_id`	string	Unique branch identifier
`branch_name`	string	Human-readable branch name
`dependencies`	integer[]	Step numbers this depends on
`session_id`	string	Group related reasoning chains
`tools_used`	string[]	Tools used in this step
`external_context`	object	External data relevant to step

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 before proposing changes", "outcome": "Identified slow queries for optimization", "next_action": "analyze query execution plans", "rationale": "Understanding execution plans will reveal bottlenecks" }

With Confidence and Final Step

{ "step_number": 3, "estimated_total": 3, "purpose": "summary", "context": "Analyzed queries and tested index optimizations", "thought": "The index on user_id reduced query time from 2s to 50ms", "outcome": "Performance issue resolved with new index", "next_action": "document the change", "rationale": "Team should know about the optimization", "confidence": 0.9, "is_final_step": true }

Revision Example

{ "step_number": 4, "estimated_total": 5, "purpose": "correction", "context": "Previous analysis missed a critical join condition", "thought": "The join was causing a cartesian product, not the index", "outcome": "Corrected root cause identification", "next_action": "fix the join condition", "rationale": "This is the actual performance issue", "revises_step": 2, "revision_reason": "Overlooked critical join in initial analysis" }

Branching Example

{ "step_number": 3, "estimated_total": 6, "purpose": "exploration", "context": "Two optimization approaches identified", "thought": "Exploring the indexing approach first as it's lower risk", "outcome": "Branch created for index optimization testing", "next_action": "test index performance", "rationale": "This approach has lower risk than query rewrite", "branch_from": 2, "branch_id": "index-optimization", "branch_name": "Index-based optimization" }

When to Use CRASH

Good fit:

Complex multi-step problem solving
Code analysis and optimization
System design with multiple considerations
Debugging requiring systematic investigation
Exploring multiple solution paths
Tasks where you need to track confidence

Not needed:

Simple, single-step tasks
Pure information retrieval
Deterministic procedures with no uncertainty

Development

npm install # Install dependencies npm run build # Build TypeScript npm run dev # Run with MCP inspector npm start # Start built server

Troubleshooting

Try using bunx instead of npx:

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

Try the experimental VM modules flag:

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

Credits

MCP Sequential Thinking Server - Primary inspiration
MCP Protocol Specification

Author

Nikko Gonzales - nikkoxgonzales

License

MIT

CRASH - Cascaded Reasoning with Adaptive Step Handling