Claude Built in commands and skills

Anthropic's Claude Code now includes built-in commands and skills that give developers direct control over context management, session flow, and execution, alongside bundled AI workflows for tasks like code review and batch refactoring. The commands, such as /context, /compact, and /plan, operate instantly without sending messages to the model, while skills like /simplify and /code-review spawn parallel subagents to automate multi-step logic. Custom skills can be configured via YAML frontmatter to control execution context, permissions, and automatic invocation.

1- Core Built-In Commands Engine & Session Controls Built-in commands execute instantly without sending a message to the model. They give you direct control over memory, model choices, and terminal execution. Context & Memory Management /context : Opens a visual map showing context window usage. Use it to see what percentage of token budget is consumed by project files vs. conversation history. /compact instructions : Summarizes earlier turns in the chat to reclaim token space. You can append instructions like /compact preserve database migration notes. /clear : Wipes the current session history clean for a new task while keeping global memory files CLAUDE.md intact. /memory : Directly views and edits active CLAUDE.md guidelines. Session Flow & Navigation - /plan description : Switches Claude into Plan Mode. Prevents file modifications while Claude drafts a step-by-step strategy for high-level tasks. - /btw question : Asks a side question without adding it to the main conversation context or history. - /rewind alias /checkpoint : Rolls back file changes, conversation turns, or both to a prior checkpoint. - /branch name / /fork : Forks the current conversation into a new branch so you can experiment with alternative implementations without destroying your main timeline. Execution Controls - /model model : Hot-swaps models mid-session e.g., jump from Sonnet for fast refactoring to Opus for complex math/architecture . - /effort level : Adjusts reasoning depth e.g., low, medium, max depending on task complexity. - /cost / /usage / /stats : Displays API token expenditures, daily rate-limit statuses, or long-term trends. 2- Bundled & Custom Skills AI Workflows Skills are intelligent workflows. When you invoke a skill, it loads a structured prompt with specific tools, allowing Claude to execute multi-step logic or spawn parallel subagents. Essential Shipped Skills - /simplify focus : Spawns multiple review agents to analyze recently changed code for redundancies, edge-case bugs, or performance gains, then applies cleaner refactors automatically. - /code-review / /security-review : Runs automated multi-agent checks on pending diffs to identify security risks, anti-patterns, or subtle bugs. - /batch description : Decomposes large-scale, repetitive changes across an entire repository e.g., "migrate 40 endpoint signatures to use Zod" into independent units running in separate worktrees. - /loop interval prompt : Periodically runs a task on a schedule e.g., /loop 2m "check if the local build passes" . - /debug description : Reads system runtime/error logs to run structured troubleshooting. 3. How Skills Are Configured Under the Hood When building custom skills in .claude/skills//SKILL.md or .claude/commands/ , you control execution behavior via YAML Frontmatter: Frontmatter Directives Key: - context: fork : Runs the skill inside an isolated background subagent so your main chat remains clean. - disable-model-invocation : true: Prevents Claude from running this skill automatically during regular text turns—it will only run when you explicitly type /migration. - allowed-tools : Scopes down security permissions so the skill can only execute approved commands or file actions.