Claude Code essentials
Claude Code 2.1.260 commands and prompts for scoped sessions, project context, permissions, review, testing, automation, MCP, skills, and subagents.
Claude Code 2.1.260 1 page when printed
Launch and diagnose
claude start an interactive session in the current directory claude 'explain this repository' start interactively with an initial prompt claude -p 'summarize src/auth/' print one result and exit cat test.log | claude -p 'explain the failure' send standard input with a non-interactive prompt claude --version print the installed Claude Code version claude doctor check installation health and report configuration errors Scope a task
Read src/auth/; do not edit yet; map the request flow. explore the named area without writing Plan this change; list files, risks, and verification commands. require a plan with concrete impact and checks Implement issue #123; change only src/auth/ and tests/auth/. state the deliverable and writable paths Preserve the public API; ask before changing the contract. put an approval gate before an interface change Stop if credentials, network access, or a migration is required. surface capability expansion before acting Finish only after tests pass; report commands and exit codes. define completion with reproducible evidence Project instructions
/init generate or improve starter project instructions CLAUDE.md store shared instructions at the project root ~/.claude/CLAUDE.md store personal instructions for every project CLAUDE.local.md store private project instructions and keep them out of Git .claude/rules/testing.md store project rules split by path or topic @docs/testing.md import a file from inside CLAUDE.md @AGENTS.md reuse cross-agent instructions from CLAUDE.md Context
Explain @src/auth/session.ts attach one file’s full contents to the prompt Map @src/auth/ attach a directory listing, not every file’s contents /add-dir ../shared grant the current session access to another directory /context show what occupies the context window /compact keep the failing test output and current plan summarize the session with an explicit focus /clear completed-task start with empty context and name the previous conversation /rewind restore code or conversation from a checkpoint Permissions
/permissions view and edit allow, ask, and deny rules /plan fix the auth bug enter plan mode and begin the stated task claude --permission-mode plan start a read-only planning session claude --permission-mode dontAsk --allowedTools 'Read,Grep,Glob' approve listed read tools and deny anything else claude --disallowedTools 'Read(./.env)' 'Read(./secrets/**)' deny reads from two sensitive paths claude --restricted -p 'inspect this repository' run one non-interactive check with restricted tools and settings Sessions and isolation
/rename auth-refactor name the current session for later lookup claude -c continue the latest conversation for this directory claude -r auth-refactor 'finish the tests' resume a named session with a new prompt claude -r auth-refactor --fork-session resume as a copy with a new session ID /branch alternate-fix branch the conversation without creating a Git branch claude -w auth-refactor create an isolated Git worktree for a new session Model and effort
/model open the model picker /model sonnet switch models and save the default for new sessions /effort high set the current session’s reasoning effort /effort status print the current effort level claude --model sonnet --effort high choose model and effort for this launch only Review and verify
/diff inspect uncommitted and per-turn diffs interactively /code-review high review the current diff for correctness at high effort /code-review high 123 review pull request 123 at high effort /security-review check the current branch against the origin default branch for vulnerabilities /verify build and run the application to verify observed behavior Compare the diff with the acceptance criteria; cite each gap by file and line. turn unmet requirements into traceable findings Specs and tests
Restate the acceptance criteria as observable behavior before editing. turn the request into pass-or-fail observations Before refactoring, add characterization tests for current behavior. pin legacy behavior before structural changes Reproduce the bug with a failing test before changing production code. capture evidence that fails before the fix Keep existing tests; add boundary, error, and cancellation cases. cover success paths and relevant failure modes Run the narrowest relevant test first, then the full required suite. get focused feedback before the delivery gate Do not weaken assertions or remove tests solely to make the suite pass. protect the specification from test tampering If behavior changes, update the API contract and tests together. keep implementation, contract, and evidence aligned Non-interactive automation
claude -p 'review the current diff' --output-format text emit plain text and exit claude -p 'summarize the diff' --output-format json emit one JSON result object claude -p 'review the diff' --output-format stream-json --verbose emit streaming JSON events claude -p 'return a summary' --json-schema '{"type":"object","properties":{"summary":{"type":"string"}},"required":["summary"]}' validate the final JSON object against a schema claude -p 'review the diff' --max-budget-usd 1 cap API-call spending at one US dollar claude -p 'review the diff' --max-turns 8 stop with an error after eight unfinished agentic turns claude -p 'one-shot check' --no-session-persistence leave no resumable session MCP tools
claude mcp add --transport http sentry https://mcp.sentry.dev/mcp add a local-scope HTTP server configuration claude mcp list list configured servers and their connection status claude mcp get sentry inspect one server’s configuration and status claude mcp login sentry start OAuth authentication for an HTTP server /mcp inspect server status and authentication inside a session claude mcp remove sentry remove the local-scope server configuration Subagents and skills
.claude/agents/code-reviewer.md store a project-scoped subagent definition claude --agent code-reviewer run the whole session as a configured subagent /subtask inspect the parser for race conditions fork a background subagent with the current conversation /tasks view and manage background work in this session .claude/skills/fix-issue/SKILL.md store a reusable project skill /skills list discovered skills and manage their visibility /fix-issue 123 invoke a skill and pass 123 as its arguments Say it precisely to your AI
rules pack · Coding in the AI era
Coding in the AI era rules for your coding agent
Download the track's pitfalls and review checks in the format your coding agent reads.