Environment Variables

Manage environment variables for your deployed Lambda functions directly from the CLI.

Overview

The leanmcp env command provides a complete set of tools for managing environment variables on your running Lambda deployments. Changes are applied immediately (causing a cold start on next invocation).

System variables like PORT, AWS_LWA_* cannot be modified or deleted as they are required for Lambda Web Adapter.

List Environment Variables

View all environment variables for your deployment:

leanmcp env list

Options

Flag	Short	Description
`--reveal`	`-r`	Show unmasked values
`--project-id`	`-p`	Specify project ID

Examples

# Basic list (values masked)
leanmcp env list

# Show actual values
leanmcp env list --reveal

# List for specific project
leanmcp env list --project-id proj_abc123

Example Output:

Environment Variables for my-mcp-server

────────────────────────────────────────────────
  API_KEY: ••••••••
  DATABASE_URL: ••••••••
  DEBUG_MODE: ••••••••
  PORT: 8080 (system)

Total: 4 variables

With —reveal:

Environment Variables for my-mcp-server

────────────────────────────────────────────────
  API_KEY: sk-1234567890abcdef
  DATABASE_URL: postgres://user:pass@host:5432/db
  DEBUG_MODE: true
  PORT: 8080 (system)

Total: 4 variables

Set Environment Variable

Add or update an environment variable:

leanmcp env set KEY=value

Options

Flag	Short	Description
`--project-id`	`-p`	Specify project ID

Examples

# Set a single variable
leanmcp env set API_KEY=sk-1234567890abcdef

# Set for specific project
leanmcp env set DATABASE_URL=postgres://localhost:5432/db --project-id proj_abc123

# Set multiple variables at once
leanmcp env set API_KEY=sk-abc123 DEBUG_MODE=true MAX_RETRIES=3

Example Output:

Setting environment variable(s) for my-mcp-server...

Successfully updated:
  ✓ API_KEY
  ✓ DEBUG_MODE
  ✓ MAX_RETRIES

Variables updated successfully!
Note: Changes will take effect after a cold start.

Variable keys are automatically converted to uppercase and sanitized to match Lambda environment variable naming rules.

Get Environment Variable

Retrieve a specific environment variable:

leanmcp env get KEY

Options

Flag	Short	Description
`--reveal`	`-r`	Show unmasked value
`--project-id`	`-p`	Specify project ID

Examples

# Get masked value
leanmcp env get API_KEY

# Get actual value
leanmcp env get API_KEY --reveal

# Get from specific project
leanmcp env get DATABASE_URL --project-id proj_abc123

Example Output:

API_KEY=••••••••

With —reveal:

API_KEY=sk-1234567890abcdef

Remove Environment Variable

Delete an environment variable:

leanmcp env remove KEY

Options

Flag	Short	Description
`--project-id`	`-p`	Specify project ID
`--yes`	`-y`	Skip confirmation prompt

Examples

# Remove with confirmation
leanmcp env remove API_KEY

# Skip confirmation
leanmcp env remove DEBUG_MODE --yes

# Remove from specific project
leanmcp env remove OLD_CONFIG --project-id proj_abc123

Example Output:

? Are you sure you want to delete API_KEY? (y/N) y

Removing environment variable: API_KEY

Variable removed successfully!
Note: Changes will take effect after a cold start.

This action cannot be undone. The variable will be permanently deleted from your Lambda function.

Pull Environment Variables

Download environment variables to a local .env file:

leanmcp env pull

Options

Flag	Short	Description
`--output`	`-o`	Output file path (default: `.env`)
`--project-id`	`-p`	Specify project ID
`--overwrite`		Overwrite existing file without confirmation

Examples

# Pull to .env (default)
leanmcp env pull

# Pull to custom file
leanmcp env pull --output .env.production

# Overwrite without confirmation
leanmcp env pull --overwrite

# Pull from specific project
leanmcp env pull --project-id proj_abc123

Example Output:

Pulling environment variables from my-mcp-server...

Downloaded 4 variables to .env

✓ API_KEY
✓ DATABASE_URL
✓ DEBUG_MODE
✓ MAX_RETRIES

Note: System variables (PORT, AWS_LWA_*) are excluded.

Generated .env file:

# Environment variables from my-mcp-server
# Downloaded: 2026-01-21T22:12:00Z

API_KEY=sk-1234567890abcdef
DATABASE_URL=postgres://user:pass@host:5432/db
DEBUG_MODE=true
MAX_RETRIES=3

Push Environment Variables

Upload environment variables from a local .env file:

leanmcp env push

Options

Flag	Short	Description
`--file`	`-f`	Input file path (default: `.env`)
`--project-id`	`-p`	Specify project ID
`--merge`		Merge with existing variables (default)
`--replace`		Replace all existing variables

Examples

# Push from .env (merge mode)
leanmcp env push

# Push from custom file
leanmcp env push --file .env.production

# Replace all variables
leanmcp env push --replace

# Push to specific project
leanmcp env push --project-id proj_abc123

Example Output (Merge Mode):

Pushing environment variables from .env...

Parsing file...
Found 5 variables

? This will update 3 and add 2 variables. Continue? (Y/n) y

Updating variables on my-mcp-server...

Successfully updated:
  ✓ API_KEY (updated)
  ✓ DATABASE_URL (updated)
  ✓ DEBUG_MODE (updated)
  ✓ NEW_VAR_1 (added)
  ✓ NEW_VAR_2 (added)

Variables pushed successfully!
Note: Changes will take effect after a cold start.

Example Output (Replace Mode):

Pushing environment variables from .env...

⚠️  WARNING: Replace mode will delete all existing variables!

Current variables (4):
  - API_KEY
  - DATABASE_URL
  - DEBUG_MODE
  - OLD_CONFIG

New variables (3):
  + API_KEY
  + DATABASE_URL
  + NEW_CONFIG

? This will DELETE 2 variables and set 3 variables. Continue? (y/N) y

Replacing all variables on my-mcp-server...

Variables replaced successfully!
Note: Changes will take effect after a cold start.

In --replace mode, all existing user variables will be deleted and replaced with the contents of your file. System variables are always preserved.

Full Workflow Example

Complete workflow for managing environment variables:

# 1. Pull current variables to local file
leanmcp env pull --output .env.backup

# 2. Check current variables
leanmcp env list --reveal

# 3. Add new variables
leanmcp env set NEW_API_KEY=sk-new123 FEATURE_FLAG=enabled

# 4. Update .env file locally (edit as needed)
# Edit .env file...

# 5. Push updated variables
leanmcp env push

# 6. Verify changes
leanmcp env list

# 7. Get specific variable
leanmcp env get NEW_API_KEY --reveal

# 8. Remove old variable
leanmcp env remove OLD_API_KEY --yes

Protected Variables

The following variables are protected and cannot be modified: AWS Reserved:

AWS_* (all AWS-prefixed variables)

Lambda Web Adapter System:

PORT
AWS_LWA_PORT
AWS_LWA_INVOKE_MODE
AWS_LWA_READINESS_CHECK_MIN_UNHEALTHY_STATUS

These variables are automatically managed by AWS Lambda and the Lambda Web Adapter. Attempting to modify them will result in them being skipped with a warning.

Troubleshooting

Not Authenticated

Not authenticated
Run 'leanmcp login' to authenticate.

Solution: Run leanmcp login and enter your API key.

No Deployment Found

No Lambda deployment found for current project

Solution: Deploy your project first using leanmcp deploy .

Variable Name Validation

Invalid variable name: my-key
Variable names must match: /^[A-Z][A-Z0-9_]*$/

Solution: Use only uppercase letters, numbers, and underscores. Must start with a letter.

File Not Found

File not found: .env

Solution: Ensure the .env file exists or specify a different file with --file.

Parse Error

Failed to parse .env file
Invalid format at line 5: "INVALID LINE"

Solution: Ensure your .env file uses KEY=VALUE format (one per line).

Next Steps

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Environment Variables

Environment Variables

Overview

List Environment Variables

Options

Examples

Set Environment Variable

Options

Examples

Get Environment Variable

Options

Examples

Remove Environment Variable

Options

Examples

Pull Environment Variables

Options

Examples

Push Environment Variables

Options

Examples

Full Workflow Example

Protected Variables

Troubleshooting

Not Authenticated

No Deployment Found

Variable Name Validation

File Not Found

Parse Error

Next Steps

Deploy Projects

Monitor Deployments

​Environment Variables

​Overview

​List Environment Variables

​Options

​Examples

​Set Environment Variable

​Options

​Examples

​Get Environment Variable

​Options

​Examples

​Remove Environment Variable

​Options

​Examples

​Pull Environment Variables

​Options

​Examples

​Push Environment Variables

​Options

​Examples

​Full Workflow Example

​Protected Variables

​Troubleshooting

​Not Authenticated

​No Deployment Found

​Variable Name Validation

​File Not Found

​Parse Error

​Next Steps

Deploy Projects

Monitor Deployments

Environment Variables

Overview

List Environment Variables

Options

Examples

Set Environment Variable

Options

Examples

Get Environment Variable

Options

Examples

Remove Environment Variable

Options

Examples

Pull Environment Variables

Options

Examples

Push Environment Variables

Options

Examples

Full Workflow Example

Protected Variables

Troubleshooting

Not Authenticated

No Deployment Found

Variable Name Validation

File Not Found

Parse Error

Next Steps