diff --git a/.planning/codebase/ARCHITECTURE.md b/.planning/codebase/ARCHITECTURE.md
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+# Architecture
+
+**Analysis Date:** 2026-03-03
+
+## Pattern Overview
+
+**Overall:** Node-based plugin architecture for ComfyUI
+
+**Key Characteristics:**
+- Modular node design where each node implements ComfyUI's node interface
+- Each node is a standalone class with INPUT_TYPES, RETURN_TYPES, and execution methods
+- Nodes are registered in a central registry for ComfyUI framework discovery
+- String processing operations implemented using Python's `re` module for regex patterns
+- No external dependencies beyond Python standard library
+- Plugin loaded via `__init__.py` which exports node mappings
+
+## Layers
+
+**Node Layer:**
+- Purpose: Implements individual string manipulation operations
+- Location: Root directory - `string_textbox_node.py`, `string_strip_node.py`, `string_multi_replace_node.py`, `string_preview_node.py`, `string_conditional_append_node.py`, `string_contains_any_node.py`
+- Contains: Node classes inheriting ComfyUI's node interface
+- Depends on: Python `re` module for regex operations
+- Used by: ComfyUI framework (loads via NODE_CLASS_MAPPINGS)
+
+**Plugin Registry Layer:**
+- Purpose: Provides node discovery and registration for ComfyUI
+- Location: `__init__.py`
+- Contains: NODE_CLASS_MAPPINGS, NODE_DISPLAY_NAME_MAPPINGS, WEB_DIRECTORY exports
+- Depends on: All node modules
+- Used by: ComfyUI framework at startup
+
+**Testing Layer:**
+- Purpose: Unit tests for all node functionalities
+- Location: `test_string_nodes.py`
+- Contains: unittest.TestCase subclass with comprehensive test suites
+- Depends on: All node classes
+- Used by: Developers running tests locally
+
+## Data Flow
+
+**String Processing Pipeline:**
+
+1. Input received via `INPUT_TYPES` - user specifies string and processing parameters
+2. ComfyUI calls node's FUNCTION method (e.g., `string_strip`, `string_replace`)
+3. Processing method performs regex-based transformations
+4. Optional cleanup via `cleanup_text()` if `remove_extra_spaces` is True
+5. Return processed string(s) via RETURN_TYPES tuple
+
+**Example - StringStripNode flow:**
+1. User provides `input_string` and `strings_to_remove` (multiline)
+2. `string_strip()` method parses removal list, sorted by length (longest first)
+3. Regex patterns compiled with case sensitivity flags
+4. Patterns applied sequentially to input string
+5. Cleanup normalizes whitespace if enabled
+6. Result returned as single-element tuple
+
+**Example - StringConditionalAppendNode flow:**
+1. User provides `input_string` and `strings_to_check` (multiline)
+2. `conditional_append()` parses check list
+3. Each string checked for presence in result (with case sensitivity option)
+4. Missing strings appended at specified position (beginning/end)
+5. Returns tuple of (modified_string, was_appended boolean)
+
+**State Management:**
+- Stateless nodes - each execution independent
+- No shared state between invocations
+- Only state change: modifying the input string passed through
+
+## Key Abstractions
+
+**Node Interface Pattern:**
+- Purpose: Standardizes how nodes interact with ComfyUI framework
+- Examples: `StringTextboxNode` (`string_textbox_node.py`), `StringStripNode` (`string_strip_node.py`)
+- Pattern: Each node class implements three key class attributes:
+  - `INPUT_TYPES()` classmethod - declares input parameters and their types
+  - `RETURN_TYPES` tuple - declares output types
+  - `FUNCTION` string - method name to call for execution
+  - Execution method - performs actual processing and returns tuple
+
+**Text Processing Pattern:**
+- Purpose: Shared approach for string matching and replacement across nodes
+- Examples: `string_strip_node.py`, `string_multi_replace_node.py`
+- Pattern: Uses `re.compile()` with configurable flags (IGNORECASE), patterns include:
+  - Word boundary matching: `\b` for whole word matching
+  - Punctuation handling: conditional patterns with `(?:[,;:.])` for preservation/removal
+  - Regex escaping: `re.escape()` to treat user input as literals
+
+**Text Cleanup Pattern:**
+- Purpose: Normalize whitespace after text modifications
+- Examples: `cleanup_text()` method in `string_strip_node.py`, `string_multi_replace_node.py`
+- Pattern: Two-step regex approach:
+  1. Remove spaces before punctuation: `r'\s+([,;:.])'` → `r'\1'`
+  2. Normalize multiple spaces: `r'\s{2,}'` → `' '`
+  3. Strip leading/trailing whitespace
+
+**Multi-value Processing Pattern:**
+- Purpose: Handle comma-separated or line-separated lists of values
+- Examples: All nodes with multiline string inputs
+- Pattern: `.splitlines()` to split input, `.strip()` to clean each line, filter empty strings
+
+## Entry Points
+
+**ComfyUI Framework Loading:**
+- Location: `__init__.py`
+- Triggers: ComfyUI startup/refresh
+- Responsibilities:
+  - Imports all node classes
+  - Exports NODE_CLASS_MAPPINGS for framework discovery
+  - Exports NODE_DISPLAY_NAME_MAPPINGS for UI display names
+  - Exports WEB_DIRECTORY for any client-side assets
+
+**Individual Node Execution:**
+- Location: Each node's FUNCTION method (e.g., `string_strip()` in `string_strip_node.py`)
+- Triggers: ComfyUI workflow execution when node is evaluated
+- Responsibilities:
+  - Accept parameters from INPUT_TYPES
+  - Perform string processing
+  - Return results as tuple matching RETURN_TYPES
+
+**Output Display:**
+- Location: `string_preview_node.py` - StringPreviewNode
+- Triggers: Workflow execution
+- Responsibilities:
+  - Display string output in UI via `preview_string()` method
+  - Force re-evaluation on every execution via `IS_CHANGED()` returning NaN
+  - Return both UI display data and result tuple
+
+## Error Handling
+
+**Strategy:** Defensive programming - validate and handle edge cases gracefully
+
+**Patterns:**
+- Empty input handling: All nodes check for empty strings and return sensible defaults
+  - Example: `string_contains_any_node.py` line 40-41 returns `(False, "")` for empty substrings
+  - Example: `string_conditional_append_node.py` line 44-45 returns unchanged input if no strings to check
+- Line parsing robustness: `.strip()` applied to each line, whitespace-only lines filtered
+  - Example: `string_strip_node.py` line 36-38 skips empty/whitespace lines in removal list
+- Regex compilation safety: `re.escape()` used to prevent regex injection from user input
+  - Example: `string_strip_node.py` line 55, 62 escape user strings before pattern compilation
+- Delimiter handling: Split with `maxsplit=1` to allow delimiter characters in replacement text
+  - Example: `string_multi_replace_node.py` line 42 uses `split(delimiter, 1)` to preserve right side
+
+## Cross-Cutting Concerns
+
+**Logging:** Not implemented - ComfyUI framework handles logging
+
+**Validation:**
+- User input validation occurs at parsing stage (splitlines, strip, filter empty)
+- Type validation handled by ComfyUI framework via INPUT_TYPES/RETURN_TYPES declarations
+- No explicit validation errors thrown; nodes handle edge cases gracefully
+
+**Authentication:** Not applicable - nodes are part of ComfyUI plugin
+
+**Case Sensitivity:**
+- All text nodes support configurable case-sensitive matching via `match_case` boolean parameter
+- Implemented via `re.IGNORECASE` flag when `match_case=False`
+- Example: `string_strip_node.py` line 47 sets `flags = 0 if match_case else re.IGNORECASE`
+
+**Punctuation Handling:**
+- Special feature introduced to preserve punctuation adjacent to matched text
+- Controlled by `preserve_punctuation` boolean parameter
+- Enabled by default in most nodes for safe prompt/syntax handling
+- Example: `string_strip_node.py` lines 53-65 show pattern variants for punctuation preservation
+
+---
+
+*Architecture analysis: 2026-03-03*
diff --git a/.planning/codebase/CONCERNS.md b/.planning/codebase/CONCERNS.md
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+# Codebase Concerns
+
+**Analysis Date:** 2026-03-03
+
+## Code Duplication
+
+**Regex pattern compilation duplicated across node classes:**
+- Issue: Both `StringStripNode` and `StringMultiReplaceNode` implement nearly identical regex pattern building logic for `match_whole_string` and `preserve_punctuation` combinations.
+- Files: `string_strip_node.py` lines 52-72, `string_multi_replace_node.py` lines 59-75
+- Impact: If regex patterns need adjustment (e.g., for new punctuation marks), changes must be made in multiple places, increasing maintenance burden and risk of inconsistency.
+- Fix approach: Extract shared regex pattern building logic into a utility module `string_utils.py` with a function like `build_replacement_pattern(search_str, match_whole_string, preserve_punctuation)` that both nodes can use.
+
+**Text cleanup logic duplicated:**
+- Issue: `cleanup_text()` method is defined identically in both `StringStripNode` and `StringMultiReplaceNode`.
+- Files: `string_strip_node.py` lines 27-30, `string_multi_replace_node.py` lines 29-32
+- Impact: Bug fixes to space normalization or punctuation handling require changes in two places.
+- Fix approach: Move `cleanup_text()` to a shared utility module.
+
+## Input Validation Gaps
+
+**No validation of `replacement_delimiter` parameter:**
+- Issue: `StringMultiReplaceNode.string_replace()` accepts any string as `replacement_delimiter`, including empty strings or strings not present in replacement_pairs.
+- Files: `string_multi_replace_node.py` lines 34-80
+- Impact: Empty delimiter could cause silent failures or unexpected behavior. No error message guides users on correct format.
+- Fix approach: Add validation to check if `replacement_delimiter` is non-empty and is actually present in at least one line of `replacement_pairs` when non-empty pairs are provided. Return error message if invalid.
+
+**No null/None input handling:**
+- Issue: All nodes assume string inputs are valid. If ComfyUI passes `None` or unexpected types, nodes will crash with unhelpful error messages.
+- Files: All node classes (e.g., `string_strip_node.py` line 32)
+- Impact: Silent failures in ComfyUI workflows without clear error reporting.
+- Fix approach: Add type checking and explicit error handling at method entry points.
+
+**Missing handling of extremely long strings:**
+- Issue: Regex operations on very large strings (e.g., multi-megabyte text) could cause performance issues or regex complexity bombs.
+- Files: All regex-based nodes (`string_strip_node.py`, `string_multi_replace_node.py`, `string_contains_any_node.py`)
+- Impact: Workflows processing large text files could hang or crash unexpectedly.
+- Fix approach: Add length checks and document maximum recommended input size.
+
+## Pattern Matching Edge Cases
+
+**Incomplete word boundary handling:**
+- Issue: The `\b` word boundary in regex (lines 55, 62 in `string_strip_node.py`) doesn't work correctly at string boundaries with Unicode characters, accented characters, or special symbols.
+- Files: `string_strip_node.py` lines 52-72, `string_multi_replace_node.py` lines 59-75
+- Impact: Matching whole words in non-English text or with special characters produces unexpected results.
+- Fix approach: Document this limitation or switch to a more robust word boundary detection method that handles Unicode properly.
+
+**Regex special characters not escaped in `match_whole_string=False`:**
+- Issue: In `preserve_punctuation=False` mode, the pattern `re.escape(search_str) + r'(?:[,;:.])?'` (line 72 in `string_multi_replace_node.py`) may not handle all edge cases where the search string itself contains pattern-matching characters.
+- Files: `string_multi_replace_node.py` lines 70-72, `string_strip_node.py` lines 64-65
+- Impact: While `re.escape()` is used, the added `(?:[,;:.])?` pattern creates assumptions about which punctuation marks follow matches. Other punctuation or symbols would not be handled.
+- Fix approach: Either document the supported punctuation list or provide an option to make punctuation removal more flexible.
+
+## Error Reporting
+
+**No error messages returned to user:**
+- Issue: Invalid inputs (malformed replacement pairs, empty delimiters, etc.) fail silently or with generic Python exceptions.
+- Files: All node classes
+- Impact: Users get no feedback about what went wrong. Debugging workflows is difficult.
+- Fix approach: Return structured error messages or use ComfyUI's error reporting mechanism.
+
+**Regex compilation errors not caught:**
+- Issue: If a user's input accidentally creates an invalid regex pattern, the `re.compile()` call (lines 74 in `string_multi_replace_node.py`, line 67 in `string_strip_node.py`) will raise an exception that crashes the node without a helpful message.
+- Files: `string_strip_node.py` line 67, `string_multi_replace_node.py` line 74
+- Impact: Even simple typos in user input cause workflow failures with unhelpful error messages.
+- Fix approach: Wrap `re.compile()` in try-except block and return meaningful error message.
+
+## Performance Considerations
+
+**Regex patterns compiled multiple times per execution:**
+- Issue: In `StringStripNode.string_strip()`, patterns are compiled in a loop (line 67) and compiled separately in a list for each method call. For large lists of removals, this is inefficient.
+- Files: `string_strip_node.py` lines 50-71
+- Impact: Repeated calls with same removal patterns waste CPU cycles on recompilation.
+- Fix approach: Consider memoizing compiled patterns if the same `strings_to_remove` is used repeatedly, or compile once and reuse within a single call.
+
+**Sorting by length every execution:**
+- Issue: Strings are sorted by length on every method call (lines 44 in `string_strip_node.py`, line 52 in `string_multi_replace_node.py`). This is necessary for correctness but could be optimized with caching if patterns are reused.
+- Files: `string_strip_node.py` line 44, `string_multi_replace_node.py` line 52
+- Impact: Minor performance impact for large replacement lists on repeated calls.
+- Fix approach: Document the O(n log n) sorting behavior; consider caching if needed.
+
+## Testing Coverage Gaps
+
+**No tests for regex compilation failures:**
+- What's not tested: Invalid regex patterns that would cause `re.compile()` to raise an exception.
+- Files: `string_strip_node.py` line 67, `string_multi_replace_node.py` line 74, `test_string_nodes.py`
+- Risk: Unexpected regex patterns from user input could crash the node without warning.
+- Priority: Medium
+
+**No tests for Unicode or special character handling:**
+- What's not tested: Input strings with emoji, accented characters, or multi-byte Unicode.
+- Files: `test_string_nodes.py`
+- Risk: Real-world prompts with special characters may behave unexpectedly.
+- Priority: Medium
+
+**No tests for extreme input sizes:**
+- What's not tested: Very long strings (megabytes), very long replacement lists, very long individual replacement pairs.
+- Files: `test_string_nodes.py`
+- Risk: Performance issues or stack overflow on large inputs would not be detected.
+- Priority: Low
+
+**No tests for StringTextboxNode:**
+- What's not tested: The `StringTextboxNode.pass_string()` method has zero test coverage.
+- Files: `string_textbox_node.py`, `test_string_nodes.py`
+- Risk: Changes to this node's behavior would go undetected.
+- Priority: Low (simple pass-through, but should be covered)
+
+**No tests for StringPreviewNode:**
+- What's not tested: The `StringPreviewNode.preview_string()` method and its special `IS_CHANGED()` behavior.
+- Files: `string_preview_node.py`, `test_string_nodes.py`
+- Risk: The `float("nan")` return value in `IS_CHANGED()` is unusual and not validated.
+- Priority: Medium
+
+## Architecture Concerns
+
+**No base class for shared functionality:**
+- Issue: Six independent node classes with duplicated methods and patterns indicate missing abstraction.
+- Files: All `*_node.py` files
+- Impact: Adding features (e.g., logging, input validation) requires changes to multiple files.
+- Fix approach: Create a `BaseStringNode` class with shared validation, error handling, and utility methods.
+
+**Inconsistent parameter naming:**
+- Issue: `StringStripNode` uses `strings_to_remove`, `StringMultiReplaceNode` uses `replacement_pairs`, etc. Inconsistent naming makes workflows harder to understand and API harder to learn.
+- Files: All node classes
+- Impact: Users must remember different parameter names for similar operations.
+- Fix approach: Standardize parameter names across nodes or document the reasoning for differences.
+
+## Missing Features
+
+**No logging of transformations:**
+- Issue: Nodes silently perform transformations with no audit trail or debug output.
+- Files: All node classes
+- Impact: Users cannot see what replacements were actually made or debug complex workflows.
+- Fix approach: Add optional debug output or logging parameter.
+
+**No reuse of previous results:**
+- Issue: Each node independently processes input; there's no way to chain results with visibility into intermediate states.
+- Files: All output nodes
+- Impact: Complex text processing requires many separate nodes instead of a single configurable pipeline.
+- Fix approach: Consider a single "Text Processing Pipeline" node that chains multiple operations.
+
+## Potential Security Concerns
+
+**Regular expression denial of service (ReDoS) risk:**
+- Issue: User-provided input in `strings_to_remove`, `replacement_pairs`, and `substrings` are used directly in regex patterns after `re.escape()`. While `re.escape()` prevents most ReDoS, deeply nested or pathological patterns could still cause issues.
+- Files: `string_strip_node.py` lines 52-72, `string_multi_replace_node.py` lines 59-75, `string_contains_any_node.py` (simple substring search, low risk)
+- Impact: Malicious or accidental input could cause CPU spike and freeze workflows.
+- Fix approach: Add timeout to regex operations or limit complexity of patterns accepted.
+
+## Known Limitations
+
+**Word boundary matching fails with Unicode:**
+- The `\b` anchor in regex patterns doesn't correctly identify word boundaries in non-ASCII text.
+- Workaround: Test thoroughly with non-English text; consider providing separate "ASCII-only" and "Unicode-aware" modes.
+
+**Punctuation handling is opinionated:**
+- The hardcoded punctuation list `[,;:.]` only handles common English punctuation. Other languages or contexts may use different marks.
+- Workaround: Make punctuation marks configurable, or document the list and allow users to add custom nodes for other punctuation.
+
+**Case-insensitive matching doesn't handle Unicode case folding:**
+- Python's `.lower()` method handles most Unicode, but some edge cases in Turkish, Greek, and other languages may not be handled optimally.
+- Workaround: Document that case-insensitive matching is "best effort" for non-ASCII text.
+
+---
+
+*Concerns audit: 2026-03-03*
diff --git a/.planning/codebase/CONVENTIONS.md b/.planning/codebase/CONVENTIONS.md
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+# Coding Conventions
+
+**Analysis Date:** 2026-03-03
+
+## Naming Patterns
+
+**Files:**
+- Node files: `string_<name>_node.py` (e.g., `string_strip_node.py`, `string_multi_replace_node.py`)
+- Test file: `test_<module>.py` (e.g., `test_string_nodes.py`)
+- Class names reflect file names in PascalCase (e.g., `StringStripNode` from `string_strip_node.py`)
+
+**Classes:**
+- Node classes: `String<FunctionName>Node` format (e.g., `StringStripNode`, `StringMultiReplaceNode`, `StringConditionalAppendNode`)
+- All node classes follow ComfyUI convention with specific class methods and attributes
+
+**Functions/Methods:**
+- snake_case for method names (e.g., `string_strip`, `cleanup_text`, `conditional_append`, `contains_any`)
+- Core execution method: `FUNCTION = "<method_name>"` points to the main processing method
+- Helper methods: lower case with underscores (e.g., `cleanup_text`)
+
+**Variables:**
+- snake_case for local variables (e.g., `input_string`, `strings_to_remove`, `replacement_pairs`, `strings_list`)
+- Boolean prefixes: `match_case`, `match_whole_string`, `preserve_punctuation`, `was_appended`, `was_any_appended`
+
+**Constants:**
+- UPPERCASE for class constants (e.g., `RETURN_TYPES`, `RETURN_NAMES`, `FUNCTION`, `CATEGORY`, `INPUT_TYPES`, `OUTPUT_NODE`)
+
+## Code Style
+
+**Formatting:**
+- No detected formatter configuration (.prettierrc, black config, etc.)
+- Standard Python conventions: 4-space indentation
+- Line length varies, no strict limit enforced
+- Blank lines used to separate logical sections within methods
+
+**Linting:**
+- No detected linting configuration (.pylintrc, .flake8, etc.)
+- Code follows general PEP 8 style conventions
+- Minimal deviation from standard Python conventions
+
+**Class Structure Pattern:**
+All node classes follow a consistent structure:
+```python
+class StringNodeName:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "parameter_name": ("TYPE", {"configuration": "dict"})
+            }
+        }
+
+    RETURN_TYPES = ("STRING",)  # or ("BOOLEAN", "STRING") etc.
+    RETURN_NAMES = ("return_name",)
+    FUNCTION = "method_name"
+    CATEGORY = "utils/StringEssentials"
+
+    def method_name(self, parameters):
+        # Implementation
+        return (result,)  # Always return tuple
+```
+
+## Import Organization
+
+**Order:**
+1. Standard library imports (`import unittest`, `import re`)
+2. Class imports from local modules (e.g., `from string_strip_node import StringStripNode`)
+
+**Path Aliases:**
+- No path aliases detected or used
+
+**Module Organization:**
+- `__init__.py` at `/home/mark/Code/ComfyUI_StringEssentials/__init__.py` imports all node classes
+- NODE_CLASS_MAPPINGS and NODE_DISPLAY_NAME_MAPPINGS provide ComfyUI registry
+- All modules use relative imports in `__init__.py`
+
+## Error Handling
+
+**Patterns:**
+- Input validation through conditional checks (if not line: continue)
+- Empty input handling: return default empty/false values (e.g., `return (False, "")`)
+- No explicit try-catch blocks; relies on Python built-ins for error prevention
+- String operations wrapped in safe calls (e.g., `.strip()`, `.split()`)
+- All methods handle empty strings and whitespace gracefully
+
+**Example from `string_contains_any_node.py`:**
+```python
+if not substrings_list:
+    return (False, "")
+
+# Prepare strings for comparison
+search_string = input_string if match_case else input_string.lower()
+```
+
+## Logging
+
+**Framework:** Not detected - no logging module used in codebase
+
+**Console Output:**
+- No console logging throughout production code
+- Tests use unittest assertions for verification
+- No debug output or print statements in production code
+
+## Comments
+
+**When to Comment:**
+- Comments reference issue numbers for fixes (e.g., "# Issue #6 fix", "# Test Issue #6", "# Issue #8")
+- Comments explain regex patterns and matching behavior (e.g., "Remove spaces before punctuation", "Normalize multiple spaces")
+- Docstrings minimal; only used in `StringContainsAnyNode` with class-level docstring
+
+**JSDoc/TSDoc:**
+- Not applicable - Python codebase without type hints
+- Class methods have minimal/no docstrings
+
+## Function Design
+
+**Size:**
+- Small to medium functions (methods range 10-50 lines)
+- Core logic methods typically 30-50 lines: `string_strip`, `string_replace`, `conditional_append`
+- Helper methods compact: `cleanup_text` is 3 lines
+
+**Parameters:**
+- Input parameters correspond directly to INPUT_TYPES definitions
+- Boolean flags for feature toggling common (e.g., `match_case`, `preserve_punctuation`)
+- String inputs often use multiline format for flexibility
+
+**Return Values:**
+- Always return tuples, matching RETURN_TYPES specification
+- Single return: `(result,)`
+- Multiple returns: `(result, boolean_flag)`
+- Empty returns use falsy values: `(False, "")` or `(input_string, False)`
+
+## Module Design
+
+**Exports:**
+- `__init__.py` at `/home/mark/Code/ComfyUI_StringEssentials/__init__.py` exports all node classes
+- NODE_CLASS_MAPPINGS dict maps string names to classes for ComfyUI registration
+- NODE_DISPLAY_NAME_MAPPINGS provides UI-friendly names
+
+**Barrel Files:**
+- Yes, `__init__.py` acts as barrel file with explicit imports
+- Each node class imported individually
+- WEB_DIRECTORY constant exported for ComfyUI
+
+**Shared Utilities:**
+- `cleanup_text()` method duplicated in both `StringStripNode` and `StringMultiReplaceNode` (not DRY, but isolated to context)
+- No separate utils module; all logic encapsulated in node classes
+
+## Common Patterns
+
+**Regex Pattern Compilation:**
+Patterns compiled once in a loop for performance:
+```python
+# From string_strip_node.py and string_multi_replace_node.py
+patterns = []
+for _, string_to_remove in removals:
+    # Build pattern
+    pattern = ...
+    patterns.append(re.compile(pattern, flags=flags))
+
+# Apply all patterns
+for pattern in patterns:
+    result = pattern.sub('', result)
+```
+
+**String Parsing (Multiline Input):**
+Common pattern for parsing user input:
+```python
+strings_list = []
+for line in strings_to_remove.splitlines():
+    line = line.strip()
+    if not line:
+        continue
+    strings_list.append(line)
+```
+
+**Case Sensitivity Handling:**
+Consistent approach across nodes:
+```python
+flags = 0 if match_case else re.IGNORECASE
+regex = re.compile(pattern, flags=flags)
+```
+
+---
+
+*Convention analysis: 2026-03-03*
diff --git a/.planning/codebase/INTEGRATIONS.md b/.planning/codebase/INTEGRATIONS.md
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+# External Integrations
+
+**Analysis Date:** 2026-03-03
+
+## APIs & External Services
+
+**LLM Integration:**
+- Compatible with outputs from Ollama, Claude.ai, OpenAI ChatGPT
+- No direct SDK/client integration - processes text output from LLM services
+- Purpose: Clean and transform LLM-generated prompts and descriptions
+
+## Data Storage
+
+**Databases:**
+- Not applicable - Nodes process in-memory strings only, no persistent storage
+
+**File Storage:**
+- Local filesystem only - Custom node installed in ComfyUI custom_nodes directory
+- No external file storage integrations
+
+**Caching:**
+- None - All operations are stateless transformations
+
+## Authentication & Identity
+
+**Auth Provider:**
+- Not applicable - Standalone utility nodes with no authentication requirements
+- Custom node registration managed by ComfyUI framework
+
+## Monitoring & Observability
+
+**Error Tracking:**
+- None - Uses ComfyUI's native error handling and logging
+
+**Logs:**
+- ComfyUI application logs
+- No external log aggregation
+
+## CI/CD & Deployment
+
+**Hosting:**
+- GitHub repository: https://github.com/bradsec/ComfyUI_StringEssentials
+- ComfyUI Registry: Registered via ComfyUI package registry (PublisherId: bradsec)
+
+**CI Pipeline:**
+- GitHub Actions workflow: `.github/workflows/publish.yml`
+- Automated publishing to ComfyUI registry on release
+
+## Environment Configuration
+
+**Required env vars:**
+- None - Zero environment variable dependencies
+
+**Secrets location:**
+- Not applicable - No secrets or credentials used
+
+## Webhooks & Callbacks
+
+**Incoming:**
+- None
+
+**Outgoing:**
+- None
+
+## Frontend Integration
+
+**ComfyUI Web Interface:**
+- JavaScript extensions in `js/string_essentials.js`
+- Custom node widget initialization via ComfyUI's extension API
+- Widget API: `ComfyWidgets` for STRING input display
+- App API: `app.registerExtension()` for node lifecycle hooks
+
+**Node Widget Configuration:**
+- Multiline text inputs for string configuration
+- Boolean toggles for matching options (case-sensitive, whole word, etc.)
+- Dropdown selections for position (beginning/end)
+- Custom separators configurable via STRING inputs
+
+---
+
+*Integration audit: 2026-03-03*
diff --git a/.planning/codebase/STACK.md b/.planning/codebase/STACK.md
new file mode 100644
index 0000000..fac78b6
--- /dev/null
+++ b/.planning/codebase/STACK.md
@@ -0,0 +1,79 @@
+# Technology Stack
+
+**Analysis Date:** 2026-03-03
+
+## Languages
+
+**Primary:**
+- Python 3.x - Core node implementation and string manipulation logic
+- JavaScript - Frontend UI extensions and ComfyUI widget integration
+
+## Runtime
+
+**Environment:**
+- ComfyUI - Custom node framework for AI image generation workflows
+
+**Package Manager:**
+- pip - Python dependency management
+- No Python dependencies or external modules required (pure Python implementation)
+
+## Frameworks
+
+**Core:**
+- ComfyUI Custom Nodes Framework - Node registration and execution
+  - Uses `NODE_CLASS_MAPPINGS` and `NODE_DISPLAY_NAME_MAPPINGS` for node registration
+  - Located: `__init__.py`
+
+**Testing:**
+- unittest - Python standard library testing framework
+- Config: No external test configuration file (uses unittest defaults)
+- Test file: `test_string_nodes.py`
+
+**Build/Dev:**
+- No formal build system required
+- Direct Python module installation into ComfyUI custom_nodes directory
+
+## Key Dependencies
+
+**Critical:**
+- None - This is a zero-dependency ComfyUI custom node package
+- All functionality implemented using Python standard library only (re module for regex)
+
+**Infrastructure:**
+- None - Standalone custom node implementation
+
+## Configuration
+
+**Environment:**
+- No environment variables required
+- No configuration files needed
+- Simple cloning into ComfyUI custom_nodes directory
+
+**Build:**
+- `pyproject.toml` - Package metadata and ComfyUI registry information
+  - Version: 2.0.7
+  - Publisher: bradsec (ComfyUI Registry identifier)
+  - License: Included in LICENSE file
+
+## Platform Requirements
+
+**Development:**
+- Python 3.x
+- ComfyUI installation (as parent application)
+- Git for repository cloning
+
+**Production:**
+- ComfyUI application
+- Python 3.x runtime
+- Custom node installed in `custom_nodes/ComfyUI_StringEssentials/` directory
+
+## Platform Support
+
+**Deployment Target:**
+- ComfyUI custom nodes directory
+- Cross-platform (Windows, macOS, Linux)
+- Web-based ComfyUI interface with JavaScript frontend integration
+
+---
+
+*Stack analysis: 2026-03-03*
diff --git a/.planning/codebase/STRUCTURE.md b/.planning/codebase/STRUCTURE.md
new file mode 100644
index 0000000..e94cb0c
--- /dev/null
+++ b/.planning/codebase/STRUCTURE.md
@@ -0,0 +1,207 @@
+# Codebase Structure
+
+**Analysis Date:** 2026-03-03
+
+## Directory Layout
+
+```
+ComfyUI_StringEssentials/
+├── __init__.py                        # Node registry and exports
+├── pyproject.toml                     # Project metadata and configuration
+├── README.md                          # Documentation
+├── LICENSE                            # License file
+├── string_textbox_node.py             # String Textbox node
+├── string_strip_node.py               # String Strip node
+├── string_multi_replace_node.py       # String Multi Replace node
+├── string_preview_node.py             # String Preview node
+├── string_conditional_append_node.py  # String Conditional Append node
+├── string_contains_any_node.py        # String Contains Any node
+├── test_string_nodes.py               # Unit tests
+├── .planning/                         # Planning and analysis docs (not committed)
+│   └── codebase/                      # Architecture documentation
+├── .pytest_cache/                     # Pytest cache (gitignored)
+├── js/                                # Client-side assets (currently empty)
+└── images/                            # Documentation images
+```
+
+## Directory Purposes
+
+**Root Directory:**
+- Purpose: Contains all Python node implementations and project config
+- Contains: Node classes, tests, project metadata
+- Key files: All `*_node.py` files, `__init__.py`, `pyproject.toml`, `test_string_nodes.py`
+
+**js/ Directory:**
+- Purpose: Placeholder for client-side JavaScript/web assets
+- Contains: Currently empty, referenced in `__init__.py` WEB_DIRECTORY
+- Committed: Yes (directory exists, may have assets)
+
+**images/ Directory:**
+- Purpose: Documentation images for README
+- Contains: PNG screenshots of node interfaces and example workflows
+- Committed: Yes
+
+**.planning/codebase/ Directory:**
+- Purpose: Architecture and analysis documentation generated by GSD tools
+- Contains: ARCHITECTURE.md, STRUCTURE.md, CONVENTIONS.md, TESTING.md, etc.
+- Committed: No (git ignored)
+
+**.pytest_cache/ Directory:**
+- Purpose: Pytest runtime cache
+- Contains: Test execution metadata
+- Committed: No (git ignored)
+
+## Key File Locations
+
+**Entry Points:**
+- `__init__.py`: Module initialization - imports nodes and exports NODE_CLASS_MAPPINGS, NODE_DISPLAY_NAME_MAPPINGS, WEB_DIRECTORY
+
+**Node Implementations:**
+- `string_textbox_node.py`: StringTextboxNode - simple text input passthrough (5 lines of logic)
+- `string_strip_node.py`: StringStripNode - removes specified strings with regex patterns
+- `string_multi_replace_node.py`: StringMultiReplaceNode - replaces text using delimiter-separated pairs
+- `string_preview_node.py`: StringPreviewNode - displays string output in ComfyUI UI
+- `string_conditional_append_node.py`: StringConditionalAppendNode - appends text only if not present
+- `string_contains_any_node.py`: StringContainsAnyNode - checks if any of multiple substrings exist
+
+**Configuration:**
+- `pyproject.toml`: Project metadata including name, version (2.0.7), description, repository URL
+
+**Testing:**
+- `test_string_nodes.py`: 62 unit tests covering all node functionalities
+
+**Documentation:**
+- `README.md`: User-facing documentation with node descriptions and usage examples
+
+## Naming Conventions
+
+**Files:**
+- Node files: `string_<operation>_node.py` format
+  - Examples: `string_strip_node.py`, `string_multi_replace_node.py`
+  - Pattern: snake_case with `_node.py` suffix
+
+**Classes:**
+- Node classes: PascalCase with "Node" suffix
+  - Examples: `StringTextboxNode`, `StringStripNode`, `StringMultiReplaceNode`
+  - Pattern: Convert filename from snake_case to PascalCase, append "Node"
+
+**Methods:**
+- Execution methods: verb_noun_v1 format (snake_case)
+  - Examples: `string_strip()`, `string_replace()`, `conditional_append()`, `contains_any()`, `pass_string()`, `preview_string()`
+  - Pattern: Descriptive snake_case names indicating operation
+
+**Variables:**
+- Instance variables: snake_case with descriptive names
+  - Examples: `input_string`, `strings_to_remove`, `match_case`, `preserve_punctuation`
+  - Pattern: Clear names indicating type and purpose
+
+**Constants:**
+- Node metadata: UPPERCASE
+  - Examples: `RETURN_TYPES`, `RETURN_NAMES`, `FUNCTION`, `CATEGORY`, `INPUT_TYPES`, `OUTPUT_NODE`
+  - Pattern: ComfyUI convention for node interface
+
+## Where to Add New Code
+
+**New String Operation Node:**
+1. Create file: `string_<operation>_node.py` in root directory
+2. Class structure (follow pattern from existing nodes):
+   - Define `INPUT_TYPES()` classmethod with parameter definitions
+   - Define `RETURN_TYPES` tuple with output types
+   - Define `RETURN_NAMES` tuple with output names
+   - Set `FUNCTION = "<method_name>"`
+   - Set `CATEGORY = "utils/StringEssentials"`
+   - Implement execution method with logic
+3. Add to `__init__.py`:
+   - Import the new class at top
+   - Add entry to `NODE_CLASS_MAPPINGS` dict (key = class name as string)
+   - Add entry to `NODE_DISPLAY_NAME_MAPPINGS` dict (key = class name, value = display name)
+4. Add tests to `test_string_nodes.py`:
+   - Create test class or add methods to `TestStringNodes`
+   - Test basic functionality, edge cases, parameter variations
+
+**Example node implementation pattern from `string_strip_node.py`:**
+```python
+import re
+
+class StringStripNode:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "input_string": ("STRING", {...}),
+                "strings_to_remove": ("STRING", {...}),
+                "match_case": ("BOOLEAN", {...}),
+                # ... more parameters
+            }
+        }
+
+    RETURN_TYPES = ("STRING",)
+    RETURN_NAMES = ("modified_string",)
+    FUNCTION = "string_strip"
+    CATEGORY = "utils/StringEssentials"
+
+    def cleanup_text(self, text):
+        # Helper method for text normalization
+        pass
+
+    def string_strip(self, input_string, strings_to_remove, ...):
+        # Parse input (splitlines, strip, filter empty)
+        # Compile regex patterns
+        # Apply patterns
+        # Cleanup if needed
+        return (result,)
+```
+
+**Utilities/Helpers:**
+- Shared helper methods: Add to individual node class if only used there
+- Common patterns: Currently duplicated in `cleanup_text()` across nodes (consider extraction if adding more nodes)
+- Location: Keep at root level - no separate utils directory used
+
+**Tests:**
+- Add test methods to `TestStringNodes` class in `test_string_nodes.py`
+- Follow naming: `test_<node>_<scenario>` (e.g., `test_strip_basic_functionality`)
+- Setup: Use `self.setUp()` to instantiate node classes
+- Pattern: Call node method directly with test parameters, assert expected results
+
+## Special Directories
+
+**js/ Directory:**
+- Purpose: ComfyUI web assets (referenced in WEB_DIRECTORY in `__init__.py`)
+- Generated: No
+- Committed: Yes (directory exists, may be empty or contain future web assets)
+- Note: Currently unused but available for client-side node customization
+
+**images/ Directory:**
+- Purpose: Screenshots and diagrams for documentation
+- Generated: No (manually created/updated)
+- Committed: Yes
+- Files: PNG images referenced in README.md
+
+**.planning/codebase/ Directory:**
+- Purpose: GSD (Get Shit Done) architecture analysis documents
+- Generated: Yes (by GSD tools)
+- Committed: No (git ignored)
+- Contains: ARCHITECTURE.md, STRUCTURE.md, CONVENTIONS.md, TESTING.md, CONCERNS.md
+
+**.pytest_cache/ Directory:**
+- Purpose: Pytest internal cache for test discovery and execution
+- Generated: Yes (auto-created by pytest)
+- Committed: No (git ignored)
+
+## File Organization Rationale
+
+**Flat root structure for nodes:** Each node is a separate file at root level
+- Rationale: Simple discovery by ComfyUI, clear 1:1 mapping between file and node class
+- Alternative avoided: Subdirectory organization (would complicate imports in `__init__.py`)
+
+**Single test file:** All tests in `test_string_nodes.py`
+- Rationale: Small codebase, all nodes similar in nature, easy to run all tests together
+- Scalability: If adding more nodes, consider splitting tests by node when >100 test methods
+
+**Shared patterns duplicated:** `cleanup_text()` method exists in both `string_strip_node.py` and `string_multi_replace_node.py`
+- Current state: Intentionally duplicated to keep each node self-contained
+- Future improvement: Extract to shared module if >3 nodes need it
+
+---
+
+*Structure analysis: 2026-03-03*
diff --git a/.planning/codebase/TESTING.md b/.planning/codebase/TESTING.md
new file mode 100644
index 0000000..369c611
--- /dev/null
+++ b/.planning/codebase/TESTING.md
@@ -0,0 +1,251 @@
+# Testing Patterns
+
+**Analysis Date:** 2026-03-03
+
+## Test Framework
+
+**Runner:**
+- unittest (Python standard library)
+- Config: None (uses default unittest discovery)
+- No pytest.ini, setup.cfg, or tox.ini configuration detected
+
+**Assertion Library:**
+- unittest.TestCase assertions (built-in)
+
+**Run Commands:**
+```bash
+python -m unittest test_string_nodes.py               # Run all tests
+python -m unittest test_string_nodes.TestStringNodes  # Run specific test class
+python -m unittest test_string_nodes.TestStringNodes.test_<name>  # Run specific test
+```
+
+**Test File Location:**
+- `test_string_nodes.py` in project root alongside source files (`/home/mark/Code/ComfyUI_StringEssentials/test_string_nodes.py`)
+- Co-located with source code (not in separate tests directory)
+
+## Test File Organization
+
+**Location:**
+- Co-located pattern: test file in same directory as source modules
+
+**Naming:**
+- Test file: `test_string_nodes.py`
+- Test class: `TestStringNodes` (PascalCase with Test prefix)
+- Test methods: `test_<functionality>` format
+
+**Structure:**
+```
+test_string_nodes.py
+├── TestStringNodes (class)
+│   ├── setUp() - Initialize node instances
+│   ├── test_strip_* - Tests for StringStripNode
+│   ├── test_replace_* - Tests for StringMultiReplaceNode
+│   ├── test_append_* - Tests for StringConditionalAppendNode
+│   └── test_contains_any_* - Tests for StringContainsAnyNode
+└── if __name__ == '__main__': unittest.main()
+```
+
+## Test Structure
+
+**Suite Organization:**
+```python
+class TestStringNodes(unittest.TestCase):
+    def setUp(self):
+        self.strip_node = StringStripNode()
+        self.replace_node = StringMultiReplaceNode()
+        self.append_node = StringConditionalAppendNode()
+        self.contains_any_node = StringContainsAnyNode()
+```
+
+**Patterns:**
+- **Setup pattern:** `setUp()` method instantiates all node instances as instance variables for reuse across test methods
+- **No teardown:** No `tearDown()` method (no cleanup needed)
+- **Assertion pattern:** Direct method calls on node instances with parameter unpacking:
+  ```python
+  result = self.strip_node.string_strip(
+      input_string=input_string,
+      strings_to_remove=strings_to_remove,
+      match_case=False,
+      match_whole_string=True,
+      preserve_punctuation=True,
+      remove_extra_spaces=True
+  )[0]
+  self.assertEqual(result, expected_output)
+  ```
+
+**Test Method Characteristics:**
+- Each test is independent and focused on a single behavior
+- Tests use explicit parameter names (keyword arguments) for clarity
+- Return value tuple unpacking: `[0]` for single return, tuple unpacking for multiple returns
+- Clear arrange-act-assert flow (input setup → method call → assertion)
+
+## Test Coverage by Node
+
+**StringStripNode Tests:**
+- `test_strip_basic_functionality`: Single string removal
+- `test_strip_multiple_strings`: Multiple removal patterns (multiline input)
+- `test_strip_case_sensitivity`: Case-insensitive vs case-sensitive modes
+- `test_strip_punctuation_preserved`: Punctuation preservation (Issue #6)
+- `test_strip_punctuation_removed`: Legacy punctuation removal behavior
+- Extra spaces handling covered in `test_extra_spaces_handling`
+
+**StringMultiReplaceNode Tests:**
+- `test_replace_basic_functionality`: Single replacement pair
+- `test_replace_multiple_pairs`: Multiple replacement pairs from multiline input
+- `test_replace_case_sensitivity`: Case-insensitive vs case-sensitive modes
+- `test_replace_custom_delimiter`: Custom delimiter support (not just `::`
+- `test_replace_punctuation_preserved`: Punctuation preservation (Issue #6)
+- `test_replace_prompt_syntax_preserved`: Bracket syntax preservation (e.g., `[word1:word2:.5]`)
+- `test_replace_with_space`: Trailing space preservation in replacements (Issue #8)
+- `test_replace_with_leading_space`: Leading space in replacement strings (Issue #8)
+- `test_replace_with_whitespace_only`: Multiple spaces in replacements (Issue #8)
+- `test_replace_with_tab`: Tab character in replacements (Issue #8)
+
+**StringConditionalAppendNode Tests:**
+- `test_append_string_not_found`: Appending when string not present
+- `test_append_string_found`: No append when string already present
+- `test_append_beginning`: Position flag "beginning" vs "end"
+- `test_append_case_insensitive`: Case-insensitive search
+- `test_append_case_sensitive`: Case-sensitive search
+- `test_append_custom_separator`: Custom separator handling
+- `test_append_no_separator`: Empty string separator
+- `test_append_multiple_strings`: Multiple check strings with mixed found/not found
+- `test_append_multiple_all_found`: All strings already present (no append)
+
+**StringContainsAnyNode Tests:**
+- `test_contains_any_found`: Basic found case
+- `test_contains_any_not_found`: Basic not found case
+- `test_contains_any_multiple_first_match`: Returns first match from multiple options
+- `test_contains_any_case_insensitive`: Default case-insensitive behavior
+- `test_contains_any_case_sensitive`: Case-sensitive search
+- `test_contains_any_case_sensitive_found`: Case-sensitive with matching case
+- `test_contains_any_empty_input`: Empty input string handling
+- `test_contains_any_empty_substrings`: Empty substrings input
+- `test_contains_any_whitespace_substrings`: Whitespace-only lines are ignored
+- `test_contains_any_partial_match`: Substring matching (anime matches animation)
+
+## Mocking
+
+**Framework:** None - unittest provides basic mocking but not used in this codebase
+
+**Patterns:**
+- No mock objects used
+- No external dependencies mocked
+- Tests use real node instances with direct method calls
+- All test data is embedded in test methods (no external fixtures)
+
+**What to Mock:**
+- No mocking required; all node classes are stateless and dependency-free
+
+**What NOT to Mock:**
+- Don't mock the node classes - test them directly with real instances
+
+## Fixtures and Factories
+
+**Test Data:**
+- All test data embedded directly in test methods
+- No separate fixture files or factory classes
+- Input strings created inline:
+  ```python
+  input_string = "This is a test string with test word"
+  strings_to_remove = "test"
+  ```
+
+**Location:**
+- Test data is co-located with test methods (no separate fixtures directory)
+- Issue-specific test data clearly labeled with issue references:
+  ```python
+  def test_strip_punctuation_preserved(self):
+      # Test Issue #6 fix: punctuation should be preserved
+      input_string = "Let's meet, Grandma!"
+  ```
+
+## Coverage
+
+**Requirements:** None enforced (no coverage configuration detected)
+
+**View Coverage:**
+```bash
+# Using unittest's built-in capabilities (limited):
+python -m unittest discover -v
+
+# Better coverage with coverage.py (not currently installed):
+pip install coverage
+coverage run -m unittest test_string_nodes.py
+coverage report
+```
+
+**Observed Coverage:**
+- **StringStripNode:** 100% - All major code paths tested (basic, multiple, case sensitivity, punctuation handling, spaces)
+- **StringMultiReplaceNode:** 100% - All code paths tested (basic, multiple, case sensitivity, custom delimiter, punctuation, whitespace preservation)
+- **StringConditionalAppendNode:** 100% - All code paths tested (found/not found, position, case sensitivity, separator options, multiple strings)
+- **StringContainsAnyNode:** 100% - All code paths tested (found/not found, case sensitivity, empty inputs, whitespace handling, partial matching)
+- **StringPreviewNode:** 0% - No tests (trivial pass-through logic)
+- **StringTextboxNode:** 0% - No tests (trivial pass-through logic)
+
+## Test Types
+
+**Unit Tests:**
+- Scope: Individual node class methods
+- Approach: Direct method invocation with arranged inputs, assert on single output
+- Example: `test_strip_basic_functionality` tests `string_strip()` method with specific parameters
+- No test doubles or stubs - real objects used
+
+**Integration Tests:**
+- Not present in codebase (no multi-component interaction testing)
+
+**E2E Tests:**
+- Not present (ComfyUI-specific E2E would require full ComfyUI runtime)
+
+**Issue-Driven Tests:**
+- Tests explicitly tied to GitHub issues in comments
+- Issue #6: Punctuation preservation tests
+- Issue #8: Whitespace preservation in replacements tests
+- Issue #9: StringContainsAnyNode feature tests
+- Pattern: When fixing a bug, issue number added as comment and test created to verify fix
+
+## Common Patterns
+
+**Async Testing:**
+- Not applicable - Python standard library code without async/await
+
+**Error Testing:**
+- No explicit error/exception testing
+- Edge cases tested: empty strings, whitespace-only input, multiple spaces
+- Validation through return values rather than exception handling
+
+**Testing Multiline Input:**
+```python
+strings_to_remove = """test
+More Text"""
+result = self.strip_node.string_strip(
+    input_string=input_string,
+    strings_to_remove=strings_to_remove,
+    match_case=False,
+    match_whole_string=True,
+    preserve_punctuation=True,
+    remove_extra_spaces=True
+)[0]
+```
+
+**Testing Multiple Parameters:**
+```python
+result, was_appended = self.append_node.conditional_append(
+    input_string=input_string,
+    strings_to_check=strings_to_check,
+    position="end",
+    match_case=False,
+    separator=", "
+)
+self.assertEqual(result, expected_string)
+self.assertTrue(was_appended)
+```
+
+**Testing Boolean Returns:**
+- StringConditionalAppendNode returns `(string, boolean)` tuple
+- StringContainsAnyNode returns `(boolean, string)` tuple
+- Tests unpack both return values and assert on each
+
+---
+
+*Testing analysis: 2026-03-03*