mcp-guide

MCP Server Selection Guide

Quick decision matrix, then detailed sections per server.

Decision Matrix

Need	Server	Activate
Library/framework docs	Context7	/mcp-activate-context7
Complex multi-step reasoning	Sequential	/mcp-activate-sequential
Bulk code transformations	Morphllm	/mcp-activate-morphllm
UI component generation	Magic	/mcp-activate-magic
Browser automation/E2E tests	Chrome DevTools	/mcp-activate-chrome-devtools
Web scraping/crawling	Firecrawl	/mcp-activate-firecrawl
Database queries	PostgreSQL	/mcp-activate-postgres

Context7

Purpose: Official library documentation lookup and framework pattern guidance.

Use when: Import statements, framework questions, version-specific APIs, official patterns needed. Use over WebSearch: When you need curated, version-specific documentation. Skip for: Simple explanations, non-framework code, general concepts.

Triggers: import, require, from, React/Vue/Angular/Next.js keywords, library API questions.

Sequential Thinking

Purpose: Multi-step reasoning engine for complex analysis.

Use when: 3+ interconnected components, root cause analysis, architecture review, security assessment, hypothesis testing. Activated by flags: --think, --think-hard, --ultrathink. Skip for: Simple explanations, single-file changes, straightforward fixes.

Triggers: Complex debugging, system design, multi-component failure investigation.

Morphllm

Purpose: Pattern-based code editing with token optimization for bulk transformations.

Use when: Multi-file consistent edits, framework updates, style enforcement, bulk text replacements. Use over manual edits: When applying the same pattern across <10 files. Skip for: Symbol renames (use IDE/Serena), semantic operations, complex analysis.

Triggers: "update all X to Y", style enforcement, framework migration patterns.

Magic (21st.dev)

Purpose: Modern UI component generation with design system integration.

Use when: UI component requests (button, form, modal, card, table, nav), design system needs. Use over manual coding: When you need production-ready, accessible components. Skip for: Backend logic, database queries, server configuration.

Triggers: /ui, /21, responsive/accessible/interactive keywords.

Chrome DevTools

Purpose: Browser automation, debugging, and testing.

Use when: E2E test scenarios, visual testing, form submission testing, screenshot capture, accessibility testing. Use over unit tests: For integration testing, user journeys, visual validation. Skip for: Static code review, syntax checking, logic validation.

Triggers: Browser testing, screenshot requests, WCAG compliance testing.

Firecrawl

Purpose: Web scraping, search, and crawling.

Use when: Need to extract content from websites, crawl multiple pages, structured data extraction. Use over WebFetch: When you need multi-page crawling or structured extraction. Skip for: Simple single-page fetches (use WebFetch), local file operations.

PostgreSQL

Purpose: Database queries and schema exploration.

Use when: Direct database queries needed, schema exploration, data analysis. Note: Prefer a read-only connection string for production databases.

Combo Patterns

Scenario	Combo
Research + implement	Context7 (docs) → Sequential (strategy)
Build UI + validate	Magic (components) → Chrome DevTools (test)
Plan edits + execute	Sequential (plan) → Morphllm (apply)
Debug complex issue	Sequential (analyze) → Context7 (verify patterns)
Full-stack feature	Context7 (docs) + Sequential (design) + Magic (UI)

Flag-Based Activation

Flag	Servers Enabled
--think	Sequential
--think-hard	Sequential + Context7
--ultrathink	All servers
--no-mcp	None (native tools only + WebSearch fallback)