diff --git a/README.md b/README.md
index b0c19b6..8b1cf1a 100644
--- a/README.md
+++ b/README.md
@@ -34,7 +34,7 @@ Download it and try it out for free!  **https://piebald.ai/**
 > [!important]
 > **NEW (January 23, 2026): We've added all of Claude Code's ~40 system reminders to this list—see [System Reminders](#system-reminders).**
 
-This repository contains an up-to-date list of all Claude Code's various system prompts and their associated token counts as of **[Claude Code v2.1.49](https://www.npmjs.com/package/@anthropic-ai/claude-code/v/2.1.49) (February 19th, 2026).**  It also contains a [**CHANGELOG.md**](./CHANGELOG.md) for the system prompts across 103 versions since v2.0.14.  From the team behind [<img src="https://github.com/Piebald-AI/piebald/raw/main/assets/logo.svg" width="15"> **Piebald.**](https://piebald.ai/)
+This repository contains an up-to-date list of all Claude Code's various system prompts and their associated token counts as of **[Claude Code v2.1.50](https://www.npmjs.com/package/@anthropic-ai/claude-code/v/2.1.50) (February 20th, 2026).**  It also contains a [**CHANGELOG.md**](./CHANGELOG.md) for the system prompts across 104 versions since v2.0.14.  From the team behind [<img src="https://github.com/Piebald-AI/piebald/raw/main/assets/logo.svg" width="15"> **Piebald.**](https://piebald.ai/)
 
 **This repository is updated within minutes of each Claude Code release.  See the [changelog](./CHANGELOG.md), and follow [@PiebaldAI](https://x.com/PiebaldAI) on X for a summary of the system prompt changes in each release.**
 
@@ -228,18 +228,18 @@ Text for large system reminders.
 - [Tool Description: Computer](./system-prompts/tool-description-computer.md) (**161** tks) - Main description for the Chrome browser computer automation tool.
 - [Tool Description: Edit](./system-prompts/tool-description-edit.md) (**246** tks) - Tool for performing exact string replacements in files.
 - [Tool Description: EnterPlanMode](./system-prompts/tool-description-enterplanmode.md) (**878** tks) - Tool description for entering plan mode to explore and design implementation approaches.
-- [Tool Description: EnterWorktree](./system-prompts/tool-description-enterworktree.md) (**237** tks) - Tool description for the EnterWorktree tool..
+- [Tool Description: EnterWorktree](./system-prompts/tool-description-enterworktree.md) (**284** tks) - Tool description for the EnterWorktree tool..
 - [Tool Description: ExitPlanMode](./system-prompts/tool-description-exitplanmode.md) (**417** tks) - Description for the ExitPlanMode tool, which presents a plan dialog for the user to approve.
 - [Tool Description: Glob](./system-prompts/tool-description-glob.md) (**122** tks) - Tool description for file pattern matching and searching by name.
 - [Tool Description: Grep](./system-prompts/tool-description-grep.md) (**300** tks) - Tool description for content search using ripgrep.
 - [Tool Description: LSP](./system-prompts/tool-description-lsp.md) (**255** tks) - Description for the LSP tool..
 - [Tool Description: NotebookEdit](./system-prompts/tool-description-notebookedit.md) (**121** tks) - Tool description for editing Jupyter notebook cells.
-- [Tool Description: ReadFile](./system-prompts/tool-description-readfile.md) (**476** tks) - Tool description for reading files.
+- [Tool Description: ReadFile](./system-prompts/tool-description-readfile.md) (**468** tks) - Tool description for reading files.
 - [Tool Description: SendMessageTool](./system-prompts/tool-description-sendmessagetool.md) (**1241** tks) - Tool for sending messages to teammates and handling protocol requests/responses in a swarm.
 - [Tool Description: Skill](./system-prompts/tool-description-skill.md) (**326** tks) - Tool description for executing skills in the main conversation.
 - [Tool Description: Sleep](./system-prompts/tool-description-sleep.md) (**154** tks) - Tool for waiting/sleeping with early wake capability on user input.
 - [Tool Description: TaskCreate](./system-prompts/tool-description-taskcreate.md) (**558** tks) - Tool description for TaskCreate tool.
-- [Tool Description: Task](./system-prompts/tool-description-task.md) (**1228** tks) - Tool description for launching specialized sub-agents to handle complex tasks.
+- [Tool Description: Task](./system-prompts/tool-description-task.md) (**1299** tks) - Tool description for launching specialized sub-agents to handle complex tasks.
 - [Tool Description: TeamDelete](./system-prompts/tool-description-teamdelete.md) (**154** tks) - Tool description for the TeamDelete tool.
 - [Tool Description: TeammateTool](./system-prompts/tool-description-teammatetool.md) (**1642** tks) - Tool for managing teams and coordinating teammates in a swarm.
 - [Tool Description: TodoWrite](./system-prompts/tool-description-todowrite.md) (**2167** tks) - Tool description for creating and managing task lists.
diff --git a/system-prompts/tool-description-enterworktree.md b/system-prompts/tool-description-enterworktree.md
index 9bf9324..5dd2e2e 100644
--- a/system-prompts/tool-description-enterworktree.md
+++ b/system-prompts/tool-description-enterworktree.md
@@ -1,9 +1,9 @@
 <!--
 name: 'Tool Description: EnterWorktree'
 description: Tool description for the EnterWorktree tool.
-ccVersion: 2.1.48
+ccVersion: 2.1.50
 -->
-Use this tool when the user asks to work in isolation, in a worktree, or on a separate branch without affecting the main working tree. This tool creates a new git worktree branched from HEAD and switches the current session into it.
+Use this tool when the user asks to work in isolation, in a worktree, or on a separate branch without affecting the main working tree. This tool creates an isolated worktree and switches the current session into it.
 
 ## When to Use
 
@@ -13,12 +13,13 @@ Use this tool when the user asks to work in isolation, in a worktree, or on a se
 
 ## Requirements
 
-- Must be in a git repository
+- Must be in a git repository, OR have WorktreeCreate/WorktreeRemove hooks configured in settings.json
 - Must not already be in a worktree
 
 ## Behavior
 
-- Creates a new git worktree inside \`.claude/worktrees/\` with a new branch based on HEAD
+- In a git repository: creates a new git worktree inside \`.claude/worktrees/\` with a new branch based on HEAD
+- Outside a git repository: delegates to WorktreeCreate/WorktreeRemove hooks for VCS-agnostic isolation
 - Switches the session's working directory to the new worktree
 - On session exit, the user will be prompted to keep or remove the worktree
 
diff --git a/system-prompts/tool-description-readfile.md b/system-prompts/tool-description-readfile.md
index 7e34496..dc72aeb 100644
--- a/system-prompts/tool-description-readfile.md
+++ b/system-prompts/tool-description-readfile.md
@@ -1,10 +1,11 @@
 <!--
 name: 'Tool Description: ReadFile'
 description: Tool description for reading files
-ccVersion: 2.1.30
+ccVersion: 2.1.50
 variables:
   - DEFAULT_READ_LINES
   - MAX_LINE_LENGTH
+  - CONDITIONAL_READ_LINES
   - CAN_READ_PDF_FILES
   - BASH_TOOL_NAME
 -->
@@ -16,7 +17,7 @@ Usage:
 - By default, it reads up to ${DEFAULT_READ_LINES} lines starting from the beginning of the file
 - You can optionally specify a line offset and limit (especially handy for long files), but it's recommended to read the whole file by not providing these parameters
 - Any lines longer than ${MAX_LINE_LENGTH} characters will be truncated
-- Results are returned using cat -n format, with line numbers starting at 1
+${CONDITIONAL_READ_LINES}
 - This tool allows Claude Code to read images (eg PNG, JPG, etc). When reading an image file the contents are presented visually as Claude Code is a multimodal LLM.${CAN_READ_PDF_FILES()?`
 - This tool can read PDF files (.pdf). For large PDFs (more than 10 pages), you MUST provide the pages parameter to read specific page ranges (e.g., pages: "1-5"). Reading a large PDF without the pages parameter will fail. Maximum 20 pages per request.`:""}
 - This tool can read Jupyter notebooks (.ipynb files) and returns all cells with their outputs, combining code, text, and visualizations.
diff --git a/system-prompts/tool-description-task.md b/system-prompts/tool-description-task.md
index 42f60dd..d890f25 100644
--- a/system-prompts/tool-description-task.md
+++ b/system-prompts/tool-description-task.md
@@ -1,7 +1,7 @@
 <!--
 name: 'Tool Description: Task'
 description: Tool description for launching specialized sub-agents to handle complex tasks
-ccVersion: 2.1.48
+ccVersion: 2.1.50
 variables:
   - TASK_TOOL_PREAMBLE
   - TASK_TOOL
@@ -36,7 +36,8 @@ Usage notes:
 - The agent's outputs should generally be trusted
 - Clearly tell the agent whether you expect it to write code or just to do research (search, file reads, web fetches, etc.), since it is not aware of the user's intent
 - If the agent description mentions that it should be used proactively, then you should try your best to use it without the user having to ask for it first. Use your judgement.
-- If the user specifies that they want you to run agents "in parallel", you MUST send a single message with multiple ${TASK_TOOL_OBJECT.name} tool use content blocks. For example, if you need to launch both a build-validator agent and a test-runner agent in parallel, send a single message with both tool calls.${FALSE()?`
+- If the user specifies that they want you to run agents "in parallel", you MUST send a single message with multiple ${TASK_TOOL_OBJECT.name} tool use content blocks. For example, if you need to launch both a build-validator agent and a test-runner agent in parallel, send a single message with both tool calls.
+- You can optionally set \`isolation: "worktree"\` to run the agent in a temporary git worktree, giving it an isolated copy of the repository. The worktree is automatically cleaned up if the agent makes no changes; if changes are made, the worktree path and branch are returned in the result.${FALSE()?`
 - The run_in_background, name, team_name, and mode parameters are not available in this context. Only synchronous subagents are supported.`:""}
 
 Example usage: