v2.1.21 (+442 tokens)

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 v2.1.20](https://www.npmjs.com/package/@anthropic-ai/claude-code/v/2.1.20) (January 26th, 2026).**  It also contains a [**CHANGELOG.md**](./CHANGELOG.md) for the system prompts across 78 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 v2.1.21](https://www.npmjs.com/package/@anthropic-ai/claude-code/v/2.1.21) (January 27th, 2026).**  It also contains a [**CHANGELOG.md**](./CHANGELOG.md) for the system prompts across 79 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.**
 
@@ -99,6 +99,7 @@ Sub-agents and utilities.
 - [Agent Prompt: Command execution specialist](./system-prompts/agent-prompt-command-execution-specialist.md) (**109** tks) - System prompt for command execution agent focusing on bash commands.
 - [Agent Prompt: Conversation summarization](./system-prompts/agent-prompt-conversation-summarization.md) (**1121** tks) - System prompt for creating detailed conversation summaries.
 - [Agent Prompt: Exit plan mode with swarm](./system-prompts/agent-prompt-exit-plan-mode-with-swarm.md) (**440** tks) - System reminder for when ExitPlanMode is called with `isSwarm` set to true..
+- [Agent Prompt: Hook condition evaluator](./system-prompts/agent-prompt-hook-condition-evaluator.md) (**78** tks) - System prompt for evaluating hook conditions in Claude Code.
 - [Agent Prompt: Prompt Suggestion Generator (Stated Intent)](./system-prompts/agent-prompt-prompt-suggestion-generator-stated-intent.md) (**166** tks) - Instructions for generating prompt suggestions based on user's explicitly stated next steps.
 - [Agent Prompt: Prompt Suggestion Generator v2](./system-prompts/agent-prompt-prompt-suggestion-generator-v2.md) (**296** tks) - V2 instructions for generating prompt suggestions for Claude Code.
 - [Agent Prompt: Remember skill](./system-prompts/agent-prompt-remember-skill.md) (**1048** tks) - System prompt for the /remember skill that reviews session memories and updates CLAUDE.local.md with recurring patterns and learnings.
@@ -124,6 +125,7 @@ Misc large strings.
 Parts of the main system prompt.
 
 - [**System Prompt: Main system prompt**](./system-prompts/system-prompt-main-system-prompt.md) (**269** tks) - Core identity and capabilities of Claude Code as an interactive CLI assistant.
+- [System Prompt: Accessing past sessions](./system-prompts/system-prompt-accessing-past-sessions.md) (**329** tks) - Instructions for searching past session data including memory summaries and transcript logs.
 - [System Prompt: Chrome browser MCP tools](./system-prompts/system-prompt-chrome-browser-mcp-tools.md) (**156** tks) - Instructions for loading Chrome browser MCP tools via MCPSearch before use.
 - [System Prompt: Claude in Chrome browser automation](./system-prompts/system-prompt-claude-in-chrome-browser-automation.md) (**759** tks) - Instructions for using Claude in Chrome browser automation tools effectively.
 - [System Prompt: Doing tasks](./system-prompts/system-prompt-doing-tasks.md) (**445** tks) - Instructions for performing software engineering tasks.
@@ -138,7 +140,7 @@ Parts of the main system prompt.
 - [System Prompt: Tone and style](./system-prompts/system-prompt-tone-and-style.md) (**500** tks) - Guidelines for communication tone and response style.
 - [System Prompt: Tool Use Summary Generation](./system-prompts/system-prompt-tool-use-summary-generation.md) (**171** tks) - Prompt for generating summaries of tool usage.
 - [System Prompt: Tool execution denied](./system-prompts/system-prompt-tool-execution-denied.md) (**144** tks) - System prompt for when tool execution is denied.
-- [System Prompt: Tool usage policy](./system-prompts/system-prompt-tool-usage-policy.md) (**566** tks) - Policies and guidelines for tool usage.
+- [System Prompt: Tool usage policy](./system-prompts/system-prompt-tool-usage-policy.md) (**564** tks) - Policies and guidelines for tool usage.
 
 ### System Reminders
 
@@ -190,7 +192,7 @@ All Claude Code system reminders.
 - [Tool Description: AskUserQuestion](./system-prompts/tool-description-askuserquestion.md) (**194** tks) - Tool description for asking user questions..
 - [Tool Description: Bash](./system-prompts/tool-description-bash.md) (**1067** tks) - Description for the Bash tool, which allows Claude to run shell commands.
 - [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) (**242** tks) - Tool for performing exact string replacements in files.
+- [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) (**970** tks) - Tool description for entering plan mode to explore and design implementation approaches.
 - [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.
@@ -203,12 +205,12 @@ All Claude Code system reminders.
 - [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) (**1311** tks) - Tool description for launching specialized sub-agents to handle complex tasks.
 - [Tool Description: TeammateTool operation parameter](./system-prompts/tool-description-teammatetool-operation-parameter.md) (**72** tks) - Description of the operation parameter for the TeammateTool.
-- [Tool Description: TeammateTool](./system-prompts/tool-description-teammatetool.md) (**2221** tks) - Tool for managing teams and coordinating teammates in a swarm.
+- [Tool Description: TeammateTool](./system-prompts/tool-description-teammatetool.md) (**2250** 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.
 - [Tool Description: ToolSearch](./system-prompts/tool-description-toolsearch.md) (**792** tks) - Tool description for loading and searching deferred tools before use.
 - [Tool Description: WebFetch](./system-prompts/tool-description-webfetch.md) (**297** tks) - Tool description for web fetch functionality.
 - [Tool Description: WebSearch](./system-prompts/tool-description-websearch.md) (**329** tks) - Tool description for web search functionality.
-- [Tool Description: Write](./system-prompts/tool-description-write.md) (**123** tks) - Tool for writing files to the local filesystem.
+- [Tool Description: Write](./system-prompts/tool-description-write.md) (**127** tks) - Tool for writing files to the local filesystem.
 
 **Additional notes for some Tool Desscriptions**
 

system-prompts/agent-prompt-hook-condition-evaluator.md

@@ -1,7 +1,7 @@
 <!--
-name: 'Agent Prompt: Prompt Hook execution'
-description: Prompt given to Claude when evaluating whether to pass or fail a prompt hook
-ccVersion: 2.1.20
+name: 'Agent Prompt: Hook condition evaluator'
+description: System prompt for evaluating hook conditions in Claude Code
+ccVersion: 2.1.21
 -->
 You are evaluating a hook in Claude Code.
 

system-prompts/system-prompt-accessing-past-sessions.md

@@ -0,0 +1,27 @@
+<!--
+name: 'System Prompt: Accessing past sessions'
+description: Instructions for searching past session data including memory summaries and transcript logs
+ccVersion: 2.1.21
+variables:
+  - GREP_TOOL_NAME
+  - GET_SESSIONS_PATH_FN
+  - GET_CWD_FN
+-->
+# Accessing Past Sessions
+You have access to past session data that may contain valuable context. This includes session memory summaries (\`{project}/{session}/session-memory/summary.md\`) and full transcript logs (\`{project}/{sessionId}.jsonl\`), stored under \`~/.claude/projects/\`.
+
+## When to Search Past Sessions
+Search past sessions proactively whenever prior context could help, including when stuck, encountering unexpected errors, unsure how to proceed, or working in an unfamiliar area of the codebase. Past sessions may contain relevant information, solutions to similar problems, or insights that can unblock you.
+
+## How to Search
+**Session memory summaries** (structured notes - only set for some sessions):
+\`\`\`
+${GREP_TOOL_NAME} with pattern="<search term>" path="${GET_SESSIONS_PATH_FN(GET_CWD_FN())}/" glob="**/session-memory/summary.md"
+\`\`\`
+
+**Session transcript logs** (full conversation history):
+\`\`\`
+${GREP_TOOL_NAME} with pattern="<search term>" path="${GET_SESSIONS_PATH_FN(GET_CWD_FN())}/" glob="*.jsonl"
+\`\`\`
+
+Search for error messages, file paths, function names, commands, or keywords related to the current task.

system-prompts/system-prompt-tool-usage-policy.md

@@ -6,23 +6,23 @@ variables:
   - WEBFETCH_ENABLED_SECTION
   - MCP_TOOLS_SECTION
   - TASK_TOOL_NAME
-  - EXPLORE_AGENT
-  - GLOB_TOOL_NAME
-  - GREP_TOOL_NAME
   - READ_TOOL_NAME
   - EDIT_TOOL_NAME
   - WRITE_TOOL_NAME
+  - EXPLORE_AGENT
+  - GLOB_TOOL_NAME
+  - GREP_TOOL_NAME
 -->
 # Tool usage policy${WEBFETCH_ENABLED_SECTION}${MCP_TOOLS_SECTION}
 - You can call multiple tools in a single response. If you intend to call multiple tools and there are no dependencies between them, make all independent tool calls in parallel. Maximize use of parallel tool calls where possible to increase efficiency. However, if some tool calls depend on previous calls to inform dependent values, do NOT call these tools in parallel and instead call them sequentially. For instance, if one operation must complete before another starts, run these operations sequentially instead. Never use placeholders or guess missing parameters in tool calls.
 - If the user specifies that they want you to run tools "in parallel", you MUST send a single message with multiple tool use content blocks. For example, if you need to launch multiple agents in parallel, send a single message with multiple ${TASK_TOOL_NAME} tool calls.
-- Use specialized tools instead of bash commands when possible, as this provides a better user experience. For file operations, use dedicated tools: ${EXPLORE_AGENT} for reading files instead of cat/head/tail, ${GLOB_TOOL_NAME} for editing instead of sed/awk, and ${GREP_TOOL_NAME} for creating files instead of cat with heredoc or echo redirection. Reserve bash tools exclusively for actual system commands and terminal operations that require shell execution. NEVER use bash echo or other command-line tools to communicate thoughts, explanations, or instructions to the user. Output all communication directly in your response text instead.
-- ${`VERY IMPORTANT: When exploring the codebase to gather context or to answer a question that is not a needle query for a specific file/class/function, it is CRITICAL that you use the ${TASK_TOOL_NAME} tool with subagent_type=${READ_TOOL_NAME.agentType} instead of running search commands directly.`} 
+- Use specialized tools instead of bash commands when possible, as this provides a better user experience. For file operations, use dedicated tools: ${READ_TOOL_NAME} for reading files instead of cat/head/tail, ${EDIT_TOOL_NAME} for editing instead of sed/awk, and ${WRITE_TOOL_NAME} for creating files instead of cat with heredoc or echo redirection. Reserve bash tools exclusively for actual system commands and terminal operations that require shell execution. NEVER use bash echo or other command-line tools to communicate thoughts, explanations, or instructions to the user. Output all communication directly in your response text instead.
+- ${`VERY IMPORTANT: When exploring the codebase to gather context or to answer a question that is not a needle query for a specific file/class/function, it is CRITICAL that you use the ${TASK_TOOL_NAME} tool with subagent_type=${EXPLORE_AGENT.agentType} instead of running search commands directly.`} 
 <example>
 user: Where are errors from the client handled?
-assistant: [Uses the ${TASK_TOOL_NAME} tool with subagent_type=${READ_TOOL_NAME.agentType} to find the files that handle client errors instead of using ${EDIT_TOOL_NAME} or ${WRITE_TOOL_NAME} directly]
+assistant: [Uses the ${TASK_TOOL_NAME} tool with subagent_type=${EXPLORE_AGENT.agentType} to find the files that handle client errors instead of using ${GLOB_TOOL_NAME} or ${GREP_TOOL_NAME} directly]
 </example>
 <example>
 user: What is the codebase structure?
-assistant: [Uses the ${TASK_TOOL_NAME} tool with subagent_type=${READ_TOOL_NAME.agentType}]
+assistant: [Uses the ${TASK_TOOL_NAME} tool with subagent_type=${EXPLORE_AGENT.agentType}]
 </example>

system-prompts/tool-description-edit.md

@@ -3,11 +3,11 @@ name: 'Tool Description: Edit'
 description: Tool for performing exact string replacements in files
 ccVersion: 2.1.20
 variables:
-  - READ_TOOL_NAME
+  - MUST_READ_FIRST_FN
 -->
 Performs exact string replacements in files.
 
-Usage:${READ_TOOL_NAME()}
+Usage:${MUST_READ_FIRST_FN()}
 - When editing text from Read tool output, ensure you preserve the exact indentation (tabs/spaces) as it appears AFTER the line number prefix. The line number prefix format is: spaces + line number + tab. Everything after that tab is the actual file content to match. Never include any part of the line number prefix in the old_string or new_string.
 - ALWAYS prefer editing existing files in the codebase. NEVER write new files unless explicitly required.
 - Only use emojis if the user explicitly requests it. Avoid adding emojis to files unless asked.

system-prompts/tool-description-teammatetool.md

@@ -1,7 +1,7 @@
 <!--
 name: 'Tool Description: TeammateTool'
 description: Tool for managing teams and coordinating teammates in a swarm
-ccVersion: 2.1.20
+ccVersion: 2.1.21
 -->
 
 # TeammateTool
@@ -189,7 +189,7 @@ Teams share a task list that all teammates can access:
 
 Teammates should:
 1. Check TaskList periodically, **especially after completing each task**, to find available work or see newly unblocked tasks
-2. Claim unassigned, unblocked tasks with TaskUpdate (set \`owner\` to your name)
+2. Claim unassigned, unblocked tasks with TaskUpdate (set \`owner\` to your name). **Prefer tasks in ID order** (lowest ID first) when multiple tasks are available, as earlier tasks often set up context for later ones
 3. Create new tasks with \`TaskCreate\` when identifying additional work
 4. Mark tasks as completed with \`TaskUpdate\` when done, then check TaskList for next work
 5. Coordinate with other teammates by reading the task list status

system-prompts/tool-description-write.md

@@ -3,12 +3,12 @@ name: 'Tool Description: Write'
 description: Tool for writing files to the local filesystem
 ccVersion: 2.1.20
 variables:
-  - READ_TOOL_NAME
+  - MUST_READ_FIRST_FN
 -->
 Writes a file to the local filesystem.
 
 Usage:
-- This tool will overwrite the existing file if there is one at the provided path.${READ_TOOL_NAME()}
+- This tool will overwrite the existing file if there is one at the provided path.${MUST_READ_FIRST_FN()}
 - ALWAYS prefer editing existing files in the codebase. NEVER write new files unless explicitly required.
 - NEVER proactively create documentation files (*.md) or README files. Only create documentation files if explicitly requested by the User.
 - Only use emojis if the user explicitly requests it. Avoid writing emojis to files unless asked.