MCP CLI Tools Path Safety

Workflow and deploy MCP tools accept only YAML files inside the current working directory

Workflow and deploy MCP tools accept only YAML files inside the current working directory for security.

from praisonaiagents import Agent

agent = Agent(name="safe-agent", instructions="Use MCP tools with path safety checks.")
agent.start("Read the file at /home/user/docs/report.txt safely.")

The user references a YAML workflow by filename; path safety ensures only files under the current working directory are accepted.

Quick Start

1. Valid Usage

   # MCP tools accept bare YAML filenames
   workflow_validate("project.yaml")  # ✅ Works
   workflow_show("config.yml")        # ✅ Works
   deploy_validate("deploy.yaml")     # ✅ Works
   
2. Rejected Usage

   # These paths are rejected for security
   workflow_validate("../config.yaml")     # ❌ ValueError
   workflow_validate("/etc/passwd")        # ❌ ValueError
   workflow_validate("subdir/file.yaml")   # ❌ ValueError
   

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How It Works

Three MCP tools now enforce strict path validation:

Tool	Purpose	Path Requirement
workflow_validate	Validate workflow YAML	Bare filename in CWD
workflow_show	Display workflow content	Bare filename in CWD
deploy_validate	Validate deployment config	Bare filename in CWD

---

What Gets Refused

Breaking Change: Absolute paths and outside-CWD paths that previously worked are now rejected.

Path Pattern	Example	Error Message
Contains / or \	subdir/file.yaml	invalid file_path: 'subdir/file.yaml'
Contains NUL byte	file\x00.yaml	invalid file_path: 'file\x00.yaml'
Starts with .	.hidden.yaml	invalid file_path: '.hidden.yaml'
Not YAML extension	config.json	file_path must be a .yaml or .yml file
Absolute path	/etc/passwd	invalid file_path: '/etc/passwd'
Parent directory	../config.yaml	invalid file_path: '../config.yaml'
Resolves outside CWD	symlink.yaml → ../outside.yaml	invalid file_path: 'symlink.yaml'

---

Migration

If you previously used these MCP tools with absolute paths or subdirectory paths:

1. Move Files to CWD

   # Before (worked previously)
   workflow_validate("/home/user/project/workflows/main.yaml")
   workflow_validate("workflows/deploy.yaml")
   
   # After (required now)
   cp /home/user/project/workflows/main.yaml ./main.yaml
   cp workflows/deploy.yaml ./deploy.yaml
   workflow_validate("main.yaml")
   workflow_validate("deploy.yaml")
   
2. Update Tool Calls

   # Before
   deploy_validate("configs/production.yaml")
   
   # After  
   deploy_validate("production.yaml")  # file must be in CWD
   

---

Common Patterns

Workflow Management

# Validate workflow in current directory
result = workflow_validate("workflow.yaml")
if "valid" in result:
    content = workflow_show("workflow.yaml")
    print(content)

Deployment Validation

# Check deployment config
result = deploy_validate("deploy.yml") 
if "valid" in result:
    print("Deployment config is valid")
else:
    print(f"Validation failed: {result}")

Error Handling

try:
    content = workflow_show("../outside.yaml")
except Exception as e:
    print(f"Error: {e}")
    # Error: invalid file_path: '../outside.yaml'

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Best Practices

Keep YAML Files in Project Root

Place workflow and deployment YAML files in the project root directory, not in subdirectories. This matches the MCP security model.

Use Descriptive Filenames

Since you can’t use paths, use descriptive filenames like production-deploy.yaml instead of deploy/production.yaml.

Validate Before Use

Always call the validation tools before processing YAML files to catch configuration errors early.

Handle Errors Gracefully

Check for ValueError exceptions and provide helpful error messages to users when paths are rejected.

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Related

MCP Integration

Learn about MCP protocol support

CLI Tools

PraisonAI CLI command reference