MANDATORY USAGE (CRITICAL RULE)
This skill is MANDATORY for all agents in the ULTRABRAIN category.
When ULTRABRAIN is used:
- •Deep logical reasoning tasks
- •Complex architecture decisions requiring extensive analysis
- •System design (monolith vs microservices, database choices)
- •Technology selection (frameworks, libraries, patterns)
- •Long-term architectural planning (scalability, maintainability)
- •Security and compliance design
- •High-risk refactoring
- •Migrating monoliths to microservices
- •Changing core data structures or APIs
- •Performance optimizations affecting multiple modules
- •Uncertain requirements (vague requests, investigation needed)
ALL ULTRABRAIN agents MUST use the sequantial-thinking-mcp_sequentialthinking tool before making any decisions, recommendations, or plans.
Agents that MUST use this skill:
- •Atlas (when delegating to ultrabrain category)
- •Sisyphus (when working on ultrabrain tasks)
- •Prometheus (when planning architecture/complex decisions)
- •Sisyphus-Juneor-ultrabrain (ALL instances)
- •Any agent receiving
category="ultrabrain"delegation
What I do
This skill guides agents on when and how to use the server-sequential-thinking MCP tool to improve the quality of their reasoning, planning, and decision-making processes.
The sequential-thinking tool enables:
- •Step-by-step analysis with hypothesis formation and verification
- •Branching thoughts to explore alternative approaches
- •Revision of previous thoughts to reconsider decisions
- •Extension of analysis even after reaching initial conclusions
- •Expressing uncertainty when information is insufficient
When to use me
Use sequential-thinking when working on tasks that benefit from deep, structured analysis:
Trigger Categories
| Task Complexity | Use Sequential-Thinking? | Rationale |
|---|---|---|
| Trivial | NO | Single-file changes, obvious fixes, <5 min work |
| Simple | NO | 1-2 files, clear scope, <30 min work |
| Medium | NO | 3+ files but structured requirements, low ambiguity |
| Architecture | YES | System design, long-term decisions, trade-off evaluation needed |
| Complex | YES | High-risk refactoring, many dependencies, significant impact |
| Uncertain | YES | Ambiguous goals, investigation needed, unclear path forward |
Specific Scenarios
Use for ARCHITECTURE tasks:
- •System design decisions (monolith vs microservices, database choices)
- •Technology selection (frameworks, libraries, patterns)
- •Long-term architectural planning (scalability, maintainability)
- •Security and compliance design
Use for HIGH-COMPLEXITY refactoring:
- •Migrating monoliths to microservices
- •Changing core data structures or APIs
- •Removing technical debt with wide impact
- •Performance optimizations affecting multiple modules
Use for UNCERTAIN requirements:
- •User provides vague requests ("optimize data", "improve UX")
- •Need to investigate before planning
- •Multiple possible interpretations of requirements
- •Research-heavy tasks with open-ended goals
When NOT to use me
Skip sequential-thinking for:
- •Yes/no questions with clear answers
- •Syntax lookup or documentation queries
- •Single-line typo fixes
- •Adding obvious features with clear scope
- •Simple configuration changes
- •Formatting or style-only tasks
How to use me
Tool Invocation
The tool is named sequantial-thinking-mcp_sequentialthinking (note: "sequantial" is intentional, not a typo).
Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
thought | string | YES | Current thinking step content |
nextThoughtNeeded | boolean | YES | Whether another thought step is needed |
thoughtNumber | number | YES | Current thought number (1, 2, 3...) |
totalThoughts | number | YES | Estimated total thoughts (can adjust up/down) |
isRevision | boolean | NO | Whether this thought revises a previous one |
revisesThought | number | NO | If isRevision, which thought number is being reconsidered |
branchFromThought | number | NO | If branching, which thought to branch from |
branchId | string | NO | Identifier for current branch (if branching) |
needsMoreThoughts | boolean | NO | If reaching "end" but realizing more analysis needed |
Usage Pattern
- •Start with estimate: Set
thoughtNumber: 1,totalThoughts: N(your initial guess) - •Build incrementally: Each thought builds on previous analysis
- •Adjust as needed: Can increase
totalThoughtsif discovering more complexity - •Reconsider when uncertain: Use
isRevision: trueto question previous conclusions - •Branch for alternatives: Use
branchFromThoughtto explore different approaches - •Signal completion: Set
nextThoughtNeeded: falsewhen satisfied with analysis - •Can extend after "end": Use
needsMoreThoughts: trueif realizing more analysis needed
Recommended Limits
- •5-7 thoughts for typical analysis
- •Avoid overthinking (10+ thoughts) unless task is exceptionally complex
- •Use branching instead of single long thought chain for multiple alternatives
Advanced Features
Branching:
Thought 1: Analyze problem Thought 2: Consider approach A Thought 3: Branch to approach B (branchFromThought=2, branchId="alt-b") → Explore alternative without losing approach A context
Revision:
Thought 3: Decision: Use X Thought 4: Realize X has problem Y Thought 5: isRevision=true, revisesThought=3, "Reconsider: X may not work because Y"
Extension:
Thought 5: Conclusion: Use approach A Thought 6: needsMoreThoughts=true, "Wait, just realized constraint Z breaks A"
Example Scenarios
Example 1: Architecture Decision
Task: "Design authentication system for our app"
Sequential-Thinking Session:
Thought 1: Analyze requirements - what auth providers needed? (OAuth, JWT, session?) Consider: User base, security needs, existing infrastructure nextThoughtNeeded: true Thought 2: Evaluate options - NextAuth.js: Fast setup, integrates well with our stack - Custom JWT: More control, more work - Session-based: Simpler, less scalable Trade-offs: Setup time vs flexibility vs performance nextThoughtNeeded: true Thought 3: Predict long-term consequences NextAuth: Easy now, but provider updates could break things Custom JWT: More work now, but full control over upgrades Session: Scaling issues if user count grows significantly nextThoughtNeeded: true Thought 4: Formulate hypothesis Recommendation: NextAuth.js for rapid development Rationale: Our timeline is tight, NextAuth covers most providers Risk: Future provider updates require testing nextThoughtNeeded: true Thought 5: Verify hypothesis Does NextAuth align with requirements? - Provider support: Yes (Google, GitHub, email) - Security: Good, battle-tested - Timeline: Fits constraints Conclusion: Hypothesis validated nextThoughtNeeded: false
Result: Well-reasoned architecture recommendation with documented trade-offs and risks.
Example 2: Complex Refactoring
Task: "Migrate monolithic auth service to microservices"
Sequential-Thinking Session:
Thought 1: Map current dependencies Which modules depend on auth service? - User profile module (heavy coupling) - Payment gateway (needs user verification) - Analytics (tracks auth events) Risk: Breaking changes could cascade across system nextThoughtNeeded: true Thought 2: Identify failure points - Direct database access from multiple services - Shared auth token generation logic - Synchronous auth checks (latency bottlenecks) nextThoughtNeeded: true Thought 3: Design migration strategy Option A: Big bang - all at once Option B: Incremental - feature by feature Risk analysis: - A: High risk, no rollback path - B: Lower risk, but longer timeline with dual maintenance nextThoughtNeeded: true Thought 4: Plan rollback strategy If Option B fails: - Keep old service running as fallback - Feature flags to switch back - Data sync to prevent inconsistency nextThoughtNeeded: true Thought 5: Define test verification - Load test before migration - Integration tests for cross-service communication - Monitor auth latency during rollout nextThoughtNeeded: true Thought 6: Final plan Strategy: Incremental migration (Option B) Timeline: 4 phases, 2 weeks each Rollback: Feature flags, old service on standby Testing: Load test + integration tests + monitoring nextThoughtNeeded: false
Result: Safe migration plan with clear phases, rollback options, and verification steps.
Example 3: Uncertain Requirements
Task: User says "We need to optimize data performance"
Sequential-Thinking Session:
Thought 1: What does "data" mean? Possibilities: - Database query performance - API response times - Data processing pipelines - Analytics/aggregation speed Uncertainty: Cannot plan without clarifying scope nextThoughtNeeded: true Thought 2: Hypothesize use cases Branch A: User-facing performance (UI loading, API calls) Branch B: Internal performance (batch jobs, analytics) Branch C: Storage/cost optimization (database sizing, caching) Each branch has very different solutions nextThoughtNeeded: true Thought 3: Branch A exploration (UI/API) If this is the issue: - Caching strategy (Redis, CDN) - Database indexing - API response pagination nextThoughtNeeded: true Thought 4: Branch B exploration (internal) If this is the issue: - Batch job parallelization - ETL pipeline optimization - Message queuing (Kafka, RabbitMQ) nextThoughtNeeded: true Thought 5: Branch C exploration (storage) If this is the issue: - Database sharding - Data compression - Archive old data nextThoughtNeeded: true Thought 6: Formulate questions for user Before planning, ask: 1. Is this about user-facing performance (API/UI) or internal jobs? 2. What are the current pain points? (slow loading, timeouts, high costs?) 3. Any specific metrics? (response time > 2s, CPU > 80%, storage > 10TB?) 4. Any constraints? (budget, timeline, tech stack limits?) Rationale: Answers will narrow down to one branch nextThoughtNeeded: false
Result: Targeted, context-aware questions that quickly identify actual requirements.
Integration Points
Before Interview Questions
Use sequential-thinking when requirements are unclear to frame better questions:
Example: Before asking "What do you want?", first analyze:
- •What information is missing?
- •What assumptions can I make?
- •What clarifying questions will be most valuable?
Benefit: More focused, productive interview sessions.
After Explore/Librarian Research
Use sequential-thinking to synthesize multiple sources of information:
Example: After gathering context from codebase and docs, use to:
- •Identify patterns and contradictions
- •Form a coherent understanding
- •Generate informed questions or recommendations
Benefit: Deeper insights than surface-level synthesis.
Before Plan Generation
Use sequential-thinking to verify logical consistency of planned approach:
Example: Before generating tasks, analyze:
- •Does the approach address all requirements?
- •Are there logical gaps or contradictions?
- •Are dependencies correctly ordered?
- •Are acceptance criteria realistic?
Benefit: Higher-quality plans with fewer revisions.
During Complex Decisions
Use sequential-thinking when weighing alternatives:
Example: When choosing between multiple technical options:
- •Evaluate trade-offs (performance, maintainability, complexity)
- •Predict long-term consequences
- •Identify risk factors
- •Formulate justified recommendation
Benefit: Well-reasoned decisions with documented rationale.
Anti-Patterns (Don't do this)
Don't use sequential-thinking for:
- •Syntax queries ("How do I write a for loop in Python?") → Use documentation or librarian
- •Yes/no questions with clear answers → Direct answer is faster
- •Simple code changes with clear scope → Overhead not justified
- •Trivial bug fixes → Just fix it
- •Formatting/style-only tasks → Use linter or formatter
Fallback Guidance
If sequential-thinking MCP is unavailable or errors occur:
- •Continue with standard workflow - The tool enhances but is not required
- •Document uncertainty - If stuck, note what information is missing
- •Ask clarifying questions - Engage user when requirements are unclear
- •Use other agents - Oracle for architecture, Librarian for research
The skill is designed to enhance planning, not block it.
Summary
Use this skill to:
- •Make better decisions for complex, high-stakes tasks
- •Avoid overlooking important considerations
- •Provide well-reasoned recommendations with clear rationale
- •Structure your thinking when problems are ambiguous
Key principle: Sequential-thinking is a tool, not a mandate. Use it when it adds value, skip it when it doesn't.