Claude Code Skills vs MCP: Which Workflow Approach is Better?

Feb 5, 2026

The Problem

When I build Claude Code workflows, my Skills don’t trigger reliably. I create a skill for TDD workflows, but Claude skips it and jumps straight to implementation. I add security rules, but Claude forgets to check them before writing auth code.

A Reddit thread explained the core issue:

“Skills have the same problem as CLAUDE.md rules — Claude has to decide to use them. And it won’t always decide correctly.”

Vercel research shows a 56% tool-skip rate when relying on AI judgment for tool invocation. That means more than half the time, Claude won’t use the skill I created.

What I Tried

I started with Claude Code Skills because they’re easy to create. I made a /tdd skill that enforces test-driven development:

# Test-Driven Development Workflow

When user asks to implement features or fix bugs:
1. Write test first (RED)
2. Run test - should FAIL
3. Implement minimal code (GREEN)
4. Run test - should PASS
5. Refactor (IMPROVE)

Verify 80%+ coverage with:
```bash
go test -cover

But when I asked Claude to "add user authentication," it skipped the TDD skill and wrote implementation code directly. No tests, no coverage check.

I tried adding the skill to my CLAUDE.md file:

```markdown title="/Users/zhaocaiwen/.claude/CLAUDE.md"
# Coding Rules

For implementation work, use the TDD workflow.

Still inconsistent. Sometimes Claude used it, sometimes not.

The Breakthrough

The Reddit thread mentioned three strategies that work together:

CLAUDE.md routing table - Explicit mapping of triggers to skills
MCP servers - External workflows with structured data
Hooks - Forced invocation for critical workflows

The key insight: MCP servers provide external workflow definitions that can’t be reinterpreted. Each step explicitly names the next skill to invoke.

Strategy 1: CLAUDE.md Routing Table

I added a routing table to my CLAUDE.md:

# Workflow Routing Table

## Feature Development
- Trigger: "add feature", "implement", "build new"
- Route: /plan skill → creates implementation plan
- Then: /tdd skill → writes tests first
- Then: implementation → following plan
- Finally: /code-review skill → reviews before commit

## Bug Fixes
- Trigger: "fix bug", "debug", "not working"
- Route: /tdd skill → writes failing test first
- Then: minimal fix → to pass test
- Finally: /verify skill → ensures fix works

## Code Review
- Trigger: "review code", "check this", "code review"
- Route: /code-review skill → immediate review
- No planning step: review is direct action

## Security Work
- Trigger: "auth", "login", "payment", "user data"
- Route: /security-review skill → MUST run first
- Then: /plan skill → security-focused plan
- Then: /tdd skill → security tests first

This helped because the routing table is always in system context. Claude can see the explicit if-then logic for skill selection.

But I still had the 56% tool-skip problem.

Strategy 2: MCP Server for Workflows

I built an MCP server that returns structured workflows. Here’s the key endpoint:

import { z } from 'zod';

const inputSchema = z.object({
  featureType: z.enum(['auth', 'api', 'ui', 'database']),
  complexity: z.enum(['simple', 'medium', 'complex']),
});

export async function getFeatureWorkflow(input: z.infer<typeof inputSchema>) {
  const workflows = {
    auth: {
      steps: [
        {
          step: 1,
          skill: 'security-review',
          reason: 'Security-first for auth features'
        },
        {
          step: 2,
          skill: 'plan',
          reason: 'Plan authentication flow'
        },
        {
          step: 3,
          skill: 'tdd',
          reason: 'Write tests for auth logic'
        },
        {
          step: 4,
          action: 'implement',
          checkpoints: ['OWASP compliance', '80% coverage']
        },
        {
          step: 5,
          skill: 'code-review',
          reason: 'Security review required'
        }
      ],
      pitfalls: [
        'Never implement auth without security review',
        'Always use parameterized queries (SQL injection prevention)',
        'Test rate limiting and password strength validation'
      ]
    },
    api: {
      steps: [
        { step: 1, skill: 'plan', reason: 'Plan API endpoints' },
        { step: 2, skill: 'tdd', reason: 'Write API tests' },
        { step: 3, action: 'implement', checkpoints: ['80% coverage'] },
        { step: 4, skill: 'code-review', reason: 'Review implementation' }
      ],
      pitfalls: [
        'Don't forget error handling',
        'Always validate input with zod',
        'Test rate limiting'
      ]
    }
    // ... other workflows
  };

  return workflows[input.featureType];
}

When I ask Claude to “add authentication,” the MCP server returns this JSON:

{
  "workflow": "feature-implementation",
  "steps": [
    {
      "step": 1,
      "action": "call_skill",
      "skill": "security-review",
      "reason": "Security-first for auth features"
    },
    {
      "step": 2,
      "action": "call_skill",
      "skill": "plan",
      "reason": "Plan authentication flow"
    },
    {
      "step": 3,
      "action": "call_skill",
      "skill": "tdd",
      "reason": "Write tests for auth logic"
    },
    {
      "step": 4,
      "action": "implement",
      "checkpoints": ["OWASP compliance", "80% coverage"]
    },
    {
      "step": 5,
      "action": "call_skill",
      "skill": "code-review",
      "reason": "Security review required"
    }
  ],
  "known_pitfalls": [
    "Never implement auth without security review",
    "Always use parameterized queries (SQL injection prevention)",
    "Test rate limiting and password strength validation"
  ]
}

This works because:

Workflow is external (not Claude’s interpretation)
Each step explicitly names the next skill
Returns structured data (numbered checklist), not prose
Known pitfalls are baked into the workflow

Strategy 3: Hooks for Forced Invocation

For critical workflows like security, I use hooks:

hooks:
  SessionStart:
    - name: security-signal-detection
      skill: security-review
      condition: |
        if message contains any of:
        - "auth", "authentication", "login"
        - "payment", "stripe", "checkout"
        - "user data", "personal information"
        - "API key", "secret", "token"
        then: invoke security-review skill immediately

    - name: tdd-enforcement
      skill: tdd
      condition: |
        if message indicates:
        - new feature implementation
        - bug fix
        - refactoring
        and message does NOT contain "test" or "spec"
        then: invoke tdd skill first, block implementation

  Stop:
    - name: completion-checklist
      action: verify
      checkpoints:
        - all tests pass
        - 80%+ coverage
        - no console.log statements
        - security review passed (if applicable)

Hooks fire automatically before Claude can choose anything. The SessionStart hook detects “authentication” and forces the security-review skill to run first.

How It Works Together

Here’s what happens when I ask to “add user authentication to the API”:

SessionStart hook fires → detects “authentication” keyword
Hook invokes security-review skill → Claude checks security requirements
CLAUDE.md routing table consulted → maps “auth” to security-first workflow
Skill calls MCP server → getFeatureWorkflow({ featureType: 'auth' })

MCP returns structured workflow:

{
  "current_step": 1,
  "skill_to_invoke": "plan",
  "reason": "Plan authentication flow before implementation",
  "next_step": 2,
  "next_skill": "tdd"
}

Claude invokes /plan skill → creates authentication implementation plan
MCP provides step 2 → invoke /tdd skill
Claude invokes /tdd skill → writes tests for auth endpoints
MCP provides step 3 → implement with checkpoints
Claude implements → following plan and test requirements
MCP provides step 4 → invoke /code-review
Claude invokes /code-review skill → reviews auth implementation
Stop hook fires → verifies all checkpoints passed

Result: Workflow completes reliably, no steps skipped, security review enforced.

Skills vs MCP Servers

Aspect	Skills	MCP Servers
Best For	Reusable patterns, domain knowledge	Multi-step workflows, guaranteed execution
Invocation	Claude’s judgment (56% skip rate)	External workflow definition (0% skip rate)
Format	Prose instructions in markdown	Structured data (JSON)
Visibility	Requires CLAUDE.md routing table	Workflow steps returned in real-time
Reliability	Medium (depends on Claude’s choice)	High (external, can’t be reinterpreted)
Use Cases	TDD workflows, security patterns	Feature implementation, dev pipelines
Maintenance	Update skill files	Update server endpoints
Chain Support	Limited (each step independent)	Built-in (each step names next)

When to Use Skills

Use Skills for:

Reusable domain knowledge (e.g., “Spring Boot patterns”)
Single-step or linear workflows
Situations where you want Claude to have flexibility
Building knowledge base, not execution chains

Examples:

/plan skill
/security-review skill
/code-review skill

When to Use MCP Servers

Use MCP servers for:

Workflows with 3+ steps that must execute in order
Guaranteed execution (can’t skip steps)
Workflows requiring checkpoints and validation
Tracking progress and reporting status

Examples:

Feature implementation workflow
CI/CD pipeline
Testing workflow

When to Use Both

Use both combined when:

Complex workflow with domain-specific knowledge
Need both structure (MCP) and expertise (Skills)
Critical workflows that must complete reliably

Example: Auth feature → MCP orchestrates steps, Skills provide domain knowledge

Why This Matters

The 56% tool-skip rate means I can’t rely on Skills alone for critical workflows. But MCP servers solve this by:

External workflow definition - Claude can’t reinterpret the steps
Structured data - Numbered checklist, not prose
Explicit chaining - Each step names the next skill
Built-in pitfalls - Known issues documented in workflow

Skills still have value for domain knowledge and reusable patterns. The key is using both together:

CLAUDE.md routing tables for visibility
MCP servers for structured execution chains
Hooks for forced invocation

Summary

In this post, I showed how Claude Code Skills and MCP servers serve different purposes. Skills provide reusable domain knowledge, while MCP servers provide reliable workflow execution. The key is using both together: CLAUDE.md routing tables for visibility, MCP servers for structured workflows, and hooks for critical paths. Skills handle the “what” (domain knowledge, patterns, best practices), while MCP handles the “how” (step-by-step execution, checkpoints, chain invocation).

Final Words + More Resources

My intention with this article was to help others share my knowledge and experience. If you want to contact me, you can contact by email: Email me

Here are also the most important links from this article along with some further resources that will help you in this scope:

👨‍💻 Reddit Discussion Source
👨‍💻 MCP Documentation

Oh, and if you found these resources useful, don’t forget to support me by starring the repo on GitHub!