Approval Patterns for MCP Writes: Preview Diffs and Confirmation Tokens
Prevent accidental writes in MCP workflows with robust approval patterns. This deep dive covers multiple approval strategies: explicit yes/no confirmations, confirmation tokens, diff previews, and staged changes—with practical examples for create_task and update_task operations.
What This Guide Covers
This guide teaches you multiple approval patterns for safe write operations:
Approval Patterns
- Explicit yes/no: Simple confirmation before writes
- Confirmation token: Require specific token to proceed
- Diff preview: Show what will change before applying
- Staged changes: Build changes incrementally with review
- Combined patterns: Mix patterns for maximum safety
Pattern 1: Explicit Yes/No Confirmation
The simplest pattern: ask for explicit confirmation before any write:
Create Task with Confirmation
"I want to create a task in Corcava: - Title: Implement user authentication - Project: [Project ID] - Due date: 2026-02-01 Show me what will be created, then wait for me to type 'YES' or 'CONFIRM' before actually creating it. If I don't confirm, don't create the task."
What the AI does:
- Shows preview of task details
- Waits for explicit "YES" or "CONFIRM"
- Only calls
create_taskafter confirmation - If no confirmation, does nothing
Update Task with Confirmation
"I want to update task [Task ID]: - Change status to 'in_progress' - Add assignee: [Name] Show me the current task details and what will change. Wait for me to type 'APPROVE' before making the update."
What the AI does:
- Calls
get_taskto show current state - Shows what will change
- Waits for "APPROVE" confirmation
- Only calls
update_taskafter approval
Pattern 2: Confirmation Token
Require a specific token to prevent accidental confirmations:
Token-Based Confirmation
"Create a task with these details: - Title: Review API documentation - Project: [Project ID] Show me a preview. To confirm, I must type the exact token: 'CREATE-TASK-2026'. If I don't type this exact token, don't create anything."
Benefits:
- Prevents accidental "yes" responses
- Requires intentional confirmation
- Can use different tokens for different operations
Pattern 3: Diff Preview
Show exactly what will change before applying updates:
Update with Diff Preview
"Update task [Task ID]. Show me a diff of what will change: Current: - Status: open - Assignee: None - Due date: 2026-01-30 Proposed: - Status: in_progress - Assignee: John Doe - Due date: 2026-02-05 Show this diff clearly, then wait for my approval before applying."
What the AI does:
- Calls
get_taskto get current state - Creates diff showing before/after
- Displays diff in readable format
- Waits for approval before calling
update_task
Pattern 4: Staged Changes
Build changes incrementally with review at each stage:
Staged Update Process
"Let's update task [Task ID] in stages: Stage 1: Show me current task details Stage 2: Propose status change (show diff) Stage 3: After I approve status, propose assignee change (show diff) Stage 4: After I approve assignee, propose due date change (show diff) Stage 5: Apply all approved changes together Don't apply any changes until I've approved all stages."
Benefits:
- Review each change individually
- Can approve some changes, reject others
- Final batch update after all approvals
Complete Examples
Example 1: Create Task (Full Pattern)
Complete Create Task Prompt
"I want to create a task in Corcava: - Title: Implement user authentication - Description: Add JWT-based authentication to the API - Project: [Project ID] - Due date: 2026-02-01 - Assignee: [Name] First, show me a preview of what will be created. Include all fields. Then wait for me to type the confirmation token 'CREATE-AUTH-TASK' before actually creating the task. If I don't type this exact token, don't create anything."
This pattern: Combines preview + confirmation token for maximum safety
Example 2: Update Task (Diff Pattern)
Complete Update Task Prompt
"Update task [Task ID]. Here's what I want to change: - Status: from 'open' to 'in_progress' - Assignee: from 'None' to 'Jane Smith' - Due date: from '2026-01-30' to '2026-02-05' First, get the current task details. Then show me a clear diff: - What's changing (before → after) - What's staying the same After showing the diff, wait for me to type 'APPROVE UPDATE' before making any changes. If I don't approve, don't update anything."
This pattern: Shows diff + requires explicit approval
Best Practices
Safety Recommendations
- Always preview: Show what will change before applying
- Use confirmation tokens: Require specific tokens for important operations
- Show diffs: Make changes visible and clear
- Batch carefully: For multiple changes, show all diffs before applying
- Read before write: Always fetch current state before updating
- Timeout handling: If no confirmation received, don't proceed
Combining Patterns
You can combine multiple patterns for maximum safety:
Combined Pattern Example
"Create a task with these details: - Title: [Title] - Project: [Project ID] 1. Show me a preview of what will be created 2. Show me a diff (empty → new task fields) 3. Wait for me to type the confirmation token 'CREATE-TASK-2026' 4. Only after I type the exact token, create the task 5. If I don't type the token, don't create anything"
This combines: Preview + Diff + Confirmation Token
Troubleshooting
AI Proceeds Without Confirmation
Symptom: AI creates/updates without waiting for approval
Fix:
- Be more explicit: "WAIT for my confirmation"
- Use confirmation tokens instead of yes/no
- Add: "If I don't confirm, do NOT proceed"
Diff Not Clear
Symptom: Can't see what will change
Fix:
- Ask AI to format diff as "Before → After"
- Request side-by-side comparison
- Ask to highlight only changed fields
Related Resources
Write Safety Guide
Preventing accidental writes
Least Privilege Workflows
Safe write workflow patterns
MCP Security
Security best practices
Create Task Tool
Tool reference
Implement Safe Write Approvals
Use approval patterns to prevent accidental writes in MCP workflows