20 pages for sessionstart.

How the agent loop works Claude Code CLI · in the page agent-sdk/agent-loop …tinguishes them: * `"init"`: session metadata for the run. When a `SessionStart` or `Setup` hook runs during session startup, its [hook lifecycle messages](/docs/en/agent-sdk/typescript#sdkhookstar… Use Claude Code features in the SDK Claude Code CLI · in the page agent-sdk/claude-code-features …eScript SDK supports additional hook events beyond Python, including `SessionStart`, `SessionEnd`, `TeammateIdle`, and `TaskCompleted`. See the [hooks guide](/docs/en/agent-sdk/hooks) for the full eve… Intercept and control agent behavior with hooks Claude Code CLI · in the page agent-sdk/hooks …denials. See [PermissionDenied](/docs/en/hooks#permissiondenied) | | `SessionStart` | No | Yes | Session initialization… Agent SDK reference - TypeScript Claude Code CLI · in the page agent-sdk/typescript …HookResponseMessage`](#sdkhookresponsemessage). Lifecycle events for `SessionStart` and `Setup` hooks are always included and don't need this option. Some hook events, such as `Notification`, `Session… Claude Code changelog Claude Code CLI · in the page changelog …n one line * Remote sessions keep sending keep-alives while a long `SessionStart` or `Setup` hook runs, so the container is not idle-reaped mid-hook * `/goal`: repeat check-ins on long-running bac… CLI reference Claude Code CLI · in the page cli-reference …| Run [Setup](/docs/en/hooks#setup) and `SessionStart` hooks, then exit without starting a conversation… Configure cloud environments Claude Code CLI · in the page cloud-environments …t has known [proxy compatibility issues](#install-dependencies-with-a-sessionstart-hook) for package fetching. To get the versions of most of the tools in this table, ask Claude to run `check-tools`… Explore the context window Claude Code CLI · in the page context-window …the conversation | | [SessionStart hooks](/docs/en/hooks-guide#re-inject-context-after-compaction) that match the `compact` source | Claude Code runs th… Message your other Claude Code sessions Claude Code CLI · in the page cross-session-messaging …on, Claude Code exports the variable before any hook runs, including `SessionStart`. * Each session exports its own socket, never one inherited from a parent session. On macOS and Linux, Claude Cod… Extend Claude Code Claude Code CLI · in the page features-overview …fecycle events](/docs/en/hooks#hook-events) such as `PostToolUse` or `SessionStart` | You typing `/<name>`, or Claude matching the description to your task | | **Determinism** | Always fires on i… Run Claude Code programmatically Claude Code CLI · in the page headless …/en/agent-sdk/typescript#sdkhookstartedmessage), while a configured [`SessionStart`](/docs/en/hooks#sessionstart) or [`Setup`](/docs/en/hooks#setup) hook runs. These stream as the hook produces them.… Hooks reference Claude Code CLI · in the page hooks …n a decision. Events fall into three cadences: * once per session: `SessionStart` and `SessionEnd` * once per turn: `UserPromptSubmit`, `Stop`, and `StopFailure` * on every tool call inside the agen… Automate actions with hooks Claude Code CLI · in the page hooks-guide …e conversation to free space. This can lose important details. Use a `SessionStart` hook with a `compact` matcher to re-inject critical context after every compaction. Claude Code adds plain text you… Set up Claude Code in a monorepo or large codebase Claude Code CLI · in the page large-codebases …ree has no signal about which plugin that area's owners maintain. A [`SessionStart` hook](/docs/en/hooks#sessionstart) can close that gap, since Claude Code adds plain text the hook prints to stdout t… Plugins reference Claude Code CLI · in the page plugins-reference …---------------------------------------------------------------- | | `SessionStart` | When a session begins or resumes… Catch security issues as Claude writes code Claude Code CLI · in the page security-guidance …---------------------------------------------------------------- | | `SessionStart` | Bootstrap the plugin's Python environment… Self-hosted environments reference Claude Code CLI · in the page self-hosted-environments-reference …lf_hosted_runner_session_start_hook_errors_total` | `SessionStart` hooks that reported an error outcome, one per failing hook execution… Tools reference Claude Code CLI · in the page tools-reference …n/env-vars) to a shell script before launching Claude Code, or use a [SessionStart hook](/docs/en/hooks#persist-environment-variables) to populate it dynamically. ### Timeout and output limits Each… Get started with Claude Code on the web Claude Code CLI · in the page web-quickstart …lly. * Move the largest downloads out of the setup script and into a [SessionStart hook](/docs/en/cloud-environments#setup-scripts-vs-sessionstart-hooks) that launches them in the background, so the s… Week 22 · May 25–29, 2026 Claude Code CLI · in the page whats-new/2026-w22 …ode> command re-scans skill directories without restarting, and <code>SessionStart</code> hooks can return <code>reloadSkills: true</code> to make skills they install available in the same session</di…