diff --git a/src-tauri/src/commands/dependencies.rs b/src-tauri/src/commands/dependencies.rs
index 118b365..0d7a629 100644
--- a/src-tauri/src/commands/dependencies.rs
+++ b/src-tauri/src/commands/dependencies.rs
@@ -1 +1,53 @@
-// Dependency check and install commands — implemented in Task 2
+use serde::Serialize;
+use std::io::{BufRead, BufReader};
+use std::process::{Command, Stdio};
+use tauri::ipc::Channel;
+
+use crate::models::DependencyStatus;
+use crate::services::dependency_manager;
+
+#[tauri::command]
+pub fn check_dependencies() -> Vec<DependencyStatus> {
+    dependency_manager::get_all_dependency_statuses()
+}
+
+#[derive(Clone, Serialize)]
+#[serde(rename_all = "camelCase", tag = "event", content = "data")]
+pub enum InstallEvent {
+    Output { line: String },
+    Finished { success: bool },
+}
+
+#[tauri::command]
+pub async fn install_dependency(
+    name: String,
+    on_event: Channel<InstallEvent>,
+) -> Result<(), String> {
+    let args = dependency_manager::get_install_args(&name)?;
+    let (cmd, cmd_args) = args.split_first().ok_or("Empty install command")?;
+
+    let mut child = Command::new(cmd)
+        .args(cmd_args)
+        .stdout(Stdio::piped())
+        .stderr(Stdio::piped())
+        .spawn()
+        .map_err(|e| format!("Failed to start install: {e}"))?;
+
+    if let Some(stdout) = child.stdout.take() {
+        let reader = BufReader::new(stdout);
+        for line in reader.lines().map_while(Result::ok) {
+            let _ = on_event.send(InstallEvent::Output { line });
+        }
+    }
+
+    let status = child.wait().map_err(|e| format!("Install failed: {e}"))?;
+    let _ = on_event.send(InstallEvent::Finished {
+        success: status.success(),
+    });
+
+    if status.success() {
+        Ok(())
+    } else {
+        Err("Install command exited with non-zero status".to_string())
+    }
+}
diff --git a/src-tauri/src/lib.rs b/src-tauri/src/lib.rs
index 309d5d3..b6de1fb 100644
--- a/src-tauri/src/lib.rs
+++ b/src-tauri/src/lib.rs
@@ -2,6 +2,8 @@ mod commands;
 mod models;
 mod services;
 
+use commands::dependencies;
+
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
     tauri::Builder::default()
@@ -9,6 +11,10 @@ pub fn run() {
         .plugin(tauri_plugin_dialog::init())
         .plugin(tauri_plugin_store::Builder::new().build())
         .plugin(tauri_plugin_process::init())
+        .invoke_handler(tauri::generate_handler![
+            dependencies::check_dependencies,
+            dependencies::install_dependency,
+        ])
         .run(tauri::generate_context!())
         .expect("error while running tauri application");
 }
diff --git a/src-tauri/src/services/dependency_manager.rs b/src-tauri/src/services/dependency_manager.rs
index 8fdbf19..2d533a9 100644
--- a/src-tauri/src/services/dependency_manager.rs
+++ b/src-tauri/src/services/dependency_manager.rs
@@ -1 +1,131 @@
-// Implemented in Task 2
+use crate::models::DependencyStatus;
+use std::process::Command;
+
+pub fn check_tool_exists(name: &str) -> Option<String> {
+    let output = Command::new("which").arg(name).output().ok()?;
+
+    if output.status.success() {
+        let version_output = Command::new(name).arg("--version").output().ok()?;
+        let version = String::from_utf8_lossy(&version_output.stdout)
+            .lines()
+            .next()
+            .unwrap_or("")
+            .trim()
+            .to_string();
+        Some(version)
+    } else {
+        None
+    }
+}
+
+pub fn check_js_runtime() -> Option<String> {
+    check_tool_exists("deno").or_else(|| check_tool_exists("node"))
+}
+
+pub fn check_pot_plugin() -> bool {
+    let output = Command::new("yt-dlp")
+        .args(["-v", "--simulate", "https://www.youtube.com/watch?v=dQw4w9WgXcQ"])
+        .output();
+
+    match output {
+        Ok(out) => {
+            let stderr = String::from_utf8_lossy(&out.stderr);
+            stderr.contains("GetPOT")
+        }
+        Err(_) => false,
+    }
+}
+
+pub fn get_all_dependency_statuses() -> Vec<DependencyStatus> {
+    let ffmpeg = check_tool_exists("ffmpeg");
+    let ytdlp = check_tool_exists("yt-dlp");
+    let js_runtime = check_js_runtime();
+    let pot_plugin = if ytdlp.is_some() {
+        check_pot_plugin()
+    } else {
+        false
+    };
+
+    vec![
+        DependencyStatus {
+            name: "ffmpeg".to_string(),
+            installed: ffmpeg.is_some(),
+            version: ffmpeg,
+            install_command: "brew install ffmpeg".to_string(),
+        },
+        DependencyStatus {
+            name: "yt-dlp".to_string(),
+            installed: ytdlp.is_some(),
+            version: ytdlp,
+            install_command: "brew install yt-dlp".to_string(),
+        },
+        DependencyStatus {
+            name: "JavaScript runtime (deno/node)".to_string(),
+            installed: js_runtime.is_some(),
+            version: js_runtime,
+            install_command: "brew install deno".to_string(),
+        },
+        DependencyStatus {
+            name: "bgutil-ytdlp-pot-provider".to_string(),
+            installed: pot_plugin,
+            version: None,
+            install_command: "python3 -m pip install -U bgutil-ytdlp-pot-provider".to_string(),
+        },
+    ]
+}
+
+pub fn get_install_args(dep_name: &str) -> Result<Vec<String>, String> {
+    match dep_name {
+        "ffmpeg" => Ok(vec![
+            "brew".into(), "install".into(), "ffmpeg".into(),
+        ]),
+        "yt-dlp" => Ok(vec![
+            "brew".into(), "install".into(), "yt-dlp".into(),
+        ]),
+        "JavaScript runtime (deno/node)" => Ok(vec![
+            "brew".into(), "install".into(), "deno".into(),
+        ]),
+        "bgutil-ytdlp-pot-provider" => Ok(vec![
+            "python3".into(), "-m".into(), "pip".into(), "install".into(), "-U".into(), "bgutil-ytdlp-pot-provider".into(),
+        ]),
+        _ => Err(format!("Unknown dependency: {dep_name}")),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_get_install_args_ffmpeg() {
+        let args = get_install_args("ffmpeg").unwrap();
+        assert_eq!(args, vec!["brew", "install", "ffmpeg"]);
+    }
+
+    #[test]
+    fn test_get_install_args_ytdlp() {
+        let args = get_install_args("yt-dlp").unwrap();
+        assert_eq!(args, vec!["brew", "install", "yt-dlp"]);
+    }
+
+    #[test]
+    fn test_get_install_args_pot_provider() {
+        let args = get_install_args("bgutil-ytdlp-pot-provider").unwrap();
+        assert_eq!(args, vec!["python3", "-m", "pip", "install", "-U", "bgutil-ytdlp-pot-provider"]);
+    }
+
+    #[test]
+    fn test_get_install_args_unknown() {
+        assert!(get_install_args("unknown-tool").is_err());
+    }
+
+    #[test]
+    fn test_dependency_statuses_has_four_entries() {
+        let statuses = get_all_dependency_statuses();
+        assert_eq!(statuses.len(), 4);
+        assert_eq!(statuses[0].name, "ffmpeg");
+        assert_eq!(statuses[1].name, "yt-dlp");
+        assert_eq!(statuses[2].name, "JavaScript runtime (deno/node)");
+        assert_eq!(statuses[3].name, "bgutil-ytdlp-pot-provider");
+    }
+}
diff --git a/src/App.svelte b/src/App.svelte
index 481b1c8..655abc3 100644
--- a/src/App.svelte
+++ b/src/App.svelte
@@ -5,8 +5,15 @@
   import Timeline from '$lib/components/Timeline.svelte';
   import ClipList from '$lib/components/ClipList.svelte';
   import StatusBar from '$lib/components/StatusBar.svelte';
+  import SetupWizard from '$lib/components/SetupWizard.svelte';
+
+  let showSetupWizard = $state(true);
 </script>
 
+{#if showSetupWizard}
+  <SetupWizard onComplete={() => (showSetupWizard = false)} />
+{/if}
+
 <div class="app-shell">
   <header class="toolbar">
     <UrlInput />
diff --git a/src/lib/bindings/dependencies.ts b/src/lib/bindings/dependencies.ts
new file mode 100644
index 0000000..8bddc17
--- /dev/null
+++ b/src/lib/bindings/dependencies.ts
@@ -0,0 +1,39 @@
+import { invoke, Channel } from '@tauri-apps/api/core';
+
+export interface DependencyStatus {
+  name: string;
+  installed: boolean;
+  version: string | null;
+  installCommand: string;
+}
+
+type InstallEvent =
+  | { event: 'output'; data: { line: string } }
+  | { event: 'finished'; data: { success: boolean } };
+
+export async function checkDependencies(): Promise<DependencyStatus[]> {
+  return invoke<DependencyStatus[]>('check_dependencies');
+}
+
+export async function installDependency(
+  name: string,
+  onOutput: (line: string) => void,
+  onFinished: (success: boolean) => void
+): Promise<void> {
+  const onEvent = new Channel<InstallEvent>();
+  onEvent.onmessage = (message) => {
+    switch (message.event) {
+      case 'output':
+        onOutput(message.data.line);
+        break;
+      case 'finished':
+        onFinished(message.data.success);
+        break;
+      default: {
+        const _exhaustive: never = message;
+        throw new Error(`Unhandled install event: ${(_exhaustive as InstallEvent).event}`);
+      }
+    }
+  };
+  await invoke('install_dependency', { name, onEvent });
+}
diff --git a/src/lib/components/SetupWizard.svelte b/src/lib/components/SetupWizard.svelte
new file mode 100644
index 0000000..953aa41
--- /dev/null
+++ b/src/lib/components/SetupWizard.svelte
@@ -0,0 +1,227 @@
+<script lang="ts">
+  import {
+    checkDependencies,
+    installDependency,
+    type DependencyStatus,
+  } from '$lib/bindings/dependencies';
+
+  let {
+    onComplete,
+  }: {
+    onComplete: () => void;
+  } = $props();
+
+  let statuses = $state<DependencyStatus[]>([]);
+  let loading = $state(true);
+  let installingIndex = $state<number | null>(null);
+  let installLog = $state<string[]>([]);
+  let installError = $state<string | null>(null);
+
+  $effect(() => {
+    runChecks();
+  });
+
+  async function runChecks() {
+    loading = true;
+    statuses = await checkDependencies();
+    loading = false;
+
+    const allMet = statuses.every((s) => s.installed);
+    if (allMet) {
+      onComplete();
+    }
+  }
+
+  async function install(index: number) {
+    const dep = statuses[index];
+    installingIndex = index;
+    installLog = [];
+    installError = null;
+
+    try {
+      await installDependency(
+        dep.name,
+        (line) => {
+          installLog = [...installLog, line];
+        },
+        (success) => {
+          if (!success) {
+            installError = 'Installation failed. Check the log for details.';
+          }
+        }
+      );
+      await runChecks();
+    } catch (e) {
+      installError = String(e);
+    } finally {
+      installingIndex = null;
+    }
+  }
+
+  function skip() {
+    const criticalMet = statuses[0]?.installed && statuses[1]?.installed;
+    if (criticalMet) {
+      onComplete();
+    }
+  }
+
+  let criticalMet = $derived(statuses[0]?.installed && statuses[1]?.installed);
+</script>
+
+{#if loading}
+  <div class="wizard-overlay">
+    <div class="wizard">
+      <h2>Checking dependencies…</h2>
+    </div>
+  </div>
+{:else}
+  <div class="wizard-overlay">
+    <div class="wizard">
+      <h2>Setup</h2>
+      <p class="subtitle">
+        Video Clipper requires a few tools to work. Let's make sure they're installed.
+      </p>
+
+      <ul class="dep-list">
+        {#each statuses as dep, i}
+          <li class="dep-row">
+            <span class="dep-status">
+              {#if dep.installed}
+                ✅
+              {:else if installingIndex === i}
+                ⏳
+              {:else}
+                ❌
+              {/if}
+            </span>
+            <span class="dep-info">
+              <strong>{dep.name}</strong>
+              {#if dep.version}
+                <span class="version">{dep.version}</span>
+              {/if}
+            </span>
+            {#if !dep.installed && installingIndex === null}
+              <button onclick={() => install(i)}>Install</button>
+            {/if}
+          </li>
+        {/each}
+      </ul>
+
+      {#if installLog.length > 0}
+        <div class="log-area">
+          {#each installLog as line}
+            <div class="log-line">{line}</div>
+          {/each}
+        </div>
+      {/if}
+
+      {#if installError}
+        <div class="error">{installError}</div>
+      {/if}
+
+      <div class="wizard-actions">
+        {#if criticalMet}
+          <button class="primary" onclick={skip}>
+            {statuses.every((s) => s.installed) ? 'Continue' : 'Skip optional & Continue'}
+          </button>
+        {:else}
+          <p class="hint">ffmpeg and yt-dlp are required to continue.</p>
+        {/if}
+      </div>
+    </div>
+  </div>
+{/if}
+
+<style>
+  .wizard-overlay {
+    position: fixed;
+    inset: 0;
+    background: rgba(0, 0, 0, 0.7);
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    z-index: 1000;
+  }
+
+  .wizard {
+    background: var(--bg-secondary);
+    border: 1px solid var(--border);
+    border-radius: 12px;
+    padding: 24px 32px;
+    max-width: 520px;
+    width: 100%;
+  }
+
+  h2 {
+    margin-bottom: 8px;
+  }
+
+  .subtitle {
+    color: var(--text-secondary);
+    margin-bottom: 16px;
+    font-size: 14px;
+  }
+
+  .dep-list {
+    list-style: none;
+    margin-bottom: 16px;
+  }
+
+  .dep-row {
+    display: flex;
+    align-items: center;
+    gap: 12px;
+    padding: 8px 0;
+    border-bottom: 1px solid var(--border);
+  }
+
+  .dep-info {
+    flex: 1;
+  }
+
+  .version {
+    color: var(--text-muted);
+    font-size: 12px;
+    margin-left: 8px;
+  }
+
+  .log-area {
+    max-height: 120px;
+    overflow-y: auto;
+    background: var(--bg-primary);
+    border-radius: 4px;
+    padding: 8px;
+    font-family: var(--font-mono);
+    font-size: 11px;
+    color: var(--text-secondary);
+    margin-bottom: 12px;
+  }
+
+  .log-line {
+    white-space: pre-wrap;
+    word-break: break-all;
+  }
+
+  .error {
+    color: var(--danger);
+    font-size: 13px;
+    margin-bottom: 12px;
+  }
+
+  .wizard-actions {
+    display: flex;
+    justify-content: flex-end;
+    gap: 12px;
+  }
+
+  .primary {
+    background: var(--accent);
+    color: var(--bg-primary);
+    font-weight: 600;
+  }
+
+  .hint {
+    color: var(--text-muted);
+    font-size: 13px;
+  }
+</style>