# Code variables in Python - Docs

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# Code variables in Python - Docs

The Python SDK (v6.9.1+) supports automatic code variables capture, allowing you to see the state of local variables when exceptions occur.

## Enabling code variables capture

Code variables capture can be enabled globally during PostHog initialization:

Python

PostHog AI

```python
from posthog import Posthog
posthog = Posthog(
    "<ph_project_token>",
    enable_exception_autocapture=True,
    capture_exception_code_variables=True,
)
```

### Scoped capture with contexts

You can enable or disable code variables capture for specific code blocks using contexts:

Python

PostHog AI

```python
from posthog import new_context
# Enable for a specific block (when disabled globally)
with new_context():
    set_capture_exception_code_variables_context(True)
    will_capture_variables()
# Disable for a specific block (when enabled globally)
with new_context():
    set_capture_exception_code_variables_context(False)
    will_not_capture_variables()
```

## Configuration options

### Masking sensitive variables

Variable names matching mask patterns will have their values replaced with `***` in the UI.

The SDK includes sensible defaults for common sensitive variable names:

Python

PostHog AI

```python
DEFAULT_CODE_VARIABLES_MASK_PATTERNS = [
    r"(?i).*password.*",
    r"(?i).*secret.*",
    r"(?i).*passwd.*",
    r"(?i).*pwd.*",
    r"(?i).*api_key.*",
    r"(?i).*apikey.*",
    r"(?i).*auth.*",
    r"(?i).*credentials.*",
    r"(?i).*privatekey.*",
    r"(?i).*private_key.*",
    r"(?i).*token.*",
]
```

#### Customizing mask patterns

Python

PostHog AI

```python
posthog = Posthog(
    "<ph_project_token>",
    enable_exception_autocapture=True,
    capture_exception_code_variables=True,
    code_variables_mask_patterns=[
        r".*password.*",    # Mask any variable containing "password"
        r".*token.*",       # Mask any variable containing "token"
        r".*secret.*",      # Mask any variable containing "secret"
        r"client_secret",   # Mask specific variable names
        r"private_key",     # Mask specific variable names
    ],
)
```

#### Scoped mask patterns

You can set mask patterns for specific code blocks using contexts:

Python

PostHog AI

```python
with new_context():
    set_code_variables_mask_patterns_context([r".*password.*"])
    mask_patterns_will_only_apply_to_this_method()
```

### Detecting secrets automatically

As a last resort, the SDK also scans captured variable *values* for high-entropy secrets that name-based masking misses — API keys, tokens, and strong passwords in innocuously-named variables — and replaces them with `***`. It recognizes common key formats (OpenAI, Anthropic, AWS, Stripe, GitHub, and more) and random high-entropy strings, while leaving identifiers like UUIDs, hashes, file paths, and URLs untouched.

This is enabled by default. To disable it globally:

Python

PostHog AI

```python
posthog = Posthog(
    "<ph_project_token>",
    enable_exception_autocapture=True,
    capture_exception_code_variables=True,
    code_variables_detect_secrets=False,
)
```

Or for a specific code block using contexts:

Python

PostHog AI

```python
with new_context():
    set_code_variables_detect_secrets_context(False)
    detection_disabled_only_here()
```

### Masking connection string credentials

Credentials embedded in connection strings and URLs are scrubbed automatically, regardless of the variable name. Only the credentials are replaced — the scheme, host, and path are kept so the value stays useful for debugging:

PostHog AI

```
postgresql://user:password@db.example.com:5432/mydb
→ postgresql://***@db.example.com:5432/mydb
```

This is enabled by default. To disable it globally:

Python

PostHog AI

```python
posthog = Posthog(
    "<ph_project_token>",
    enable_exception_autocapture=True,
    capture_exception_code_variables=True,
    code_variables_mask_url_credentials=False,
)
```

Or for a specific code block using contexts:

Python

PostHog AI

```python
with new_context():
    set_code_variables_mask_url_credentials_context(False)
    masking_disabled_only_here()
```

### Ignoring variables

Variable names matching ignore patterns are not captured at all. This is useful for excluding internal variables, temporary data, or framework-specific variables that don't provide debugging value.

By default, Python internal variables (starting with `__`) are ignored.

#### Customizing ignore patterns

Python

PostHog AI

```python
posthog = Posthog(
    "<ph_project_token>",
    enable_exception_autocapture=True,
    capture_exception_code_variables=True,
    code_variables_ignore_patterns=[
        r"^__.*",      # Python internals
        r"^_.*",       # Private variables
        r"temp_.*",    # Temporary variables
        r"cache_.*",   # Cache variables
        r"debug_.*",   # Debug variables
    ],
)
```

#### Scoped ignore patterns

You can set ignore patterns for specific code blocks using contexts:

Python

PostHog AI

```python
with new_context():
    set_code_variables_ignore_patterns_context([r"cache_.*"])
    ignore_patterns_will_only_apply_to_this_method()
```

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