diff --git a/sidecar/crates/torttube-sidecar/Cargo.toml b/sidecar/crates/torttube-sidecar/Cargo.toml
index c363fff..2e67476 100644
--- a/sidecar/crates/torttube-sidecar/Cargo.toml
+++ b/sidecar/crates/torttube-sidecar/Cargo.toml
@@ -11,4 +11,23 @@ name = "torttube-sidecar"
 path = "src/main.rs"
 
 [dependencies]
-# M1 — rustypipe (codeberg.org/ThetaDev/rustypipe), tokio, serde, serde_json, reqwest
+# Tier 1 — native Rust Innertube
+rustypipe = "0.11"
+
+# Tier 2 + 3 — yt-dlp subprocess shell-out (no library, just std::process)
+
+# Runtime + JSON-over-stdio
+tokio = { version = "1", features = ["rt-multi-thread", "macros", "io-std", "io-util", "process", "fs"] }
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+
+# Errors + logging
+anyhow = "1"
+thiserror = "1"
+tracing = "0.1"
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+
+# SponsorBlock — sha256 + REST
+sha2 = "0.10"
+hex = "0.4"
+reqwest = { version = "0.12", default-features = false, features = ["rustls-tls", "json"] }
diff --git a/sidecar/crates/torttube-sidecar/src/main.rs b/sidecar/crates/torttube-sidecar/src/main.rs
index 543e3a8..49a53d4 100644
--- a/sidecar/crates/torttube-sidecar/src/main.rs
+++ b/sidecar/crates/torttube-sidecar/src/main.rs
@@ -1,9 +1,199 @@
 // torttube-sidecar — JSON-over-stdio bridge between Kodi (Python) and YouTube extraction.
 // SPDX-License-Identifier: GPL-3.0-or-later
 //
-// Reads one JSON request per line from stdin, writes one JSON response per line to stdout.
-// M0 scaffold — handlers land in M1+ (resolve, sponsorblock, search, channel, playlist).
+// Protocol: one JSON request per line on stdin, one JSON response per line on stdout.
+// Logs go to stderr (so Kodi can capture them separately from the JSON stream).
+//
+// Ops:
+//   {"op":"resolve","id":"<yt-id>"}      Tier 1 (rustypipe) → Tier 2 (yt-dlp) fallback
+//   {"op":"rip","id":"<yt-id>","dest_dir":"<path>"}  Tier 3 (yt-dlp download)
+//   {"op":"sponsorblock","id":"<yt-id>","categories":["sponsor","selfpromo"]}
+//   {"op":"ping"}                        liveness check
+//
+// Responses always carry `ok: bool`. On `ok:false` an `error` field gives the typed reason.
 
-fn main() {
-    eprintln!("torttube-sidecar M0 scaffold — see MILESTONES.md");
+use anyhow::Context;
+use serde::{Deserialize, Serialize};
+use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
+
+mod resolve;
+mod rip;
+mod sponsor;
+
+#[derive(Debug, Deserialize)]
+#[serde(tag = "op", rename_all = "snake_case")]
+enum Request {
+    Ping,
+    Resolve { id: String },
+    Rip { id: String, dest_dir: String },
+    Sponsorblock {
+        id: String,
+        #[serde(default = "sponsor::default_categories")]
+        categories: Vec<String>,
+    },
+}
+
+#[derive(Debug, Serialize)]
+#[serde(untagged)]
+enum Response {
+    Ok(serde_json::Value),
+    Err { ok: bool, error: String, kind: ErrorKind },
+}
+
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "snake_case")]
+enum ErrorKind {
+    BadRequest,
+    AgeRestricted,
+    RegionBlocked,
+    PrivateVideo,
+    NotFound,
+    Extractor,
+    Network,
+    Io,
+    Internal,
+}
+
+impl Response {
+    fn ok(value: serde_json::Value) -> Self {
+        // Inject ok:true into the value if it's an object, otherwise wrap it.
+        let value = match value {
+            serde_json::Value::Object(mut map) => {
+                map.insert("ok".into(), serde_json::Value::Bool(true));
+                serde_json::Value::Object(map)
+            }
+            other => serde_json::json!({ "ok": true, "value": other }),
+        };
+        Response::Ok(value)
+    }
+
+    fn err(kind: ErrorKind, error: impl Into<String>) -> Self {
+        Response::Err { ok: false, kind, error: error.into() }
+    }
+}
+
+#[tokio::main(flavor = "multi_thread", worker_threads = 2)]
+async fn main() -> anyhow::Result<()> {
+    tracing_subscriber::fmt()
+        .with_env_filter(
+            tracing_subscriber::EnvFilter::try_from_env("TORTTUBE_LOG")
+                .unwrap_or_else(|_| tracing_subscriber::EnvFilter::new("info")),
+        )
+        .with_writer(std::io::stderr)
+        .init();
+
+    tracing::info!("torttube-sidecar starting (pid={})", std::process::id());
+
+    let stdin = tokio::io::stdin();
+    let mut stdout = tokio::io::stdout();
+    let mut reader = BufReader::new(stdin).lines();
+
+    while let Some(line) = reader.next_line().await? {
+        let line = line.trim();
+        if line.is_empty() {
+            continue;
+        }
+        let response = handle_line(line).await;
+        let json = serde_json::to_string(&response)
+            .unwrap_or_else(|e| format!(r#"{{"ok":false,"error":"serialize: {e}","kind":"internal"}}"#));
+        stdout.write_all(json.as_bytes()).await?;
+        stdout.write_all(b"\n").await?;
+        stdout.flush().await?;
+    }
+
+    tracing::info!("torttube-sidecar stdin closed, exiting cleanly");
+    Ok(())
+}
+
+async fn handle_line(line: &str) -> Response {
+    let req: Request = match serde_json::from_str(line) {
+        Ok(r) => r,
+        Err(e) => {
+            tracing::warn!(error = %e, "bad request");
+            return Response::err(ErrorKind::BadRequest, format!("parse: {e}"));
+        }
+    };
+
+    match req {
+        Request::Ping => Response::ok(serde_json::json!({ "pong": true })),
+        Request::Resolve { id } => match resolve::resolve(&id).await {
+            Ok(v) => Response::ok(v),
+            Err(e) => e.into(),
+        },
+        Request::Rip { id, dest_dir } => match rip::rip(&id, &dest_dir).await {
+            Ok(v) => Response::ok(v),
+            Err(e) => e.into(),
+        },
+        Request::Sponsorblock { id, categories } => match sponsor::fetch(&id, &categories).await {
+            Ok(v) => Response::ok(v),
+            Err(e) => Response::err(ErrorKind::Network, format!("sponsorblock: {e}")),
+        },
+    }
+}
+
+/// Common error returned by resolve/rip handlers — gets mapped to a typed Response.
+#[derive(Debug, thiserror::Error)]
+pub enum HandlerError {
+    #[error("age-restricted")]
+    AgeRestricted,
+    #[error("region-blocked")]
+    RegionBlocked,
+    #[error("private video")]
+    PrivateVideo,
+    #[error("not found")]
+    NotFound,
+    #[error("extractor: {0}")]
+    Extractor(String),
+    #[error("network: {0}")]
+    Network(String),
+    #[error("io: {0}")]
+    Io(String),
+    #[error("internal: {0}")]
+    Internal(String),
+}
+
+impl From<HandlerError> for Response {
+    fn from(e: HandlerError) -> Self {
+        let kind = match &e {
+            HandlerError::AgeRestricted => ErrorKind::AgeRestricted,
+            HandlerError::RegionBlocked => ErrorKind::RegionBlocked,
+            HandlerError::PrivateVideo => ErrorKind::PrivateVideo,
+            HandlerError::NotFound => ErrorKind::NotFound,
+            HandlerError::Extractor(_) => ErrorKind::Extractor,
+            HandlerError::Network(_) => ErrorKind::Network,
+            HandlerError::Io(_) => ErrorKind::Io,
+            HandlerError::Internal(_) => ErrorKind::Internal,
+        };
+        Response::err(kind, e.to_string())
+    }
+}
+
+impl From<std::io::Error> for HandlerError {
+    fn from(e: std::io::Error) -> Self {
+        HandlerError::Io(e.to_string())
+    }
+}
+
+impl From<anyhow::Error> for HandlerError {
+    fn from(e: anyhow::Error) -> Self {
+        HandlerError::Internal(e.to_string())
+    }
+}
+
+/// Small helper for shelling out to yt-dlp. Returns stdout on success, anyhow on failure.
+pub(crate) async fn run_yt_dlp(args: &[&str]) -> anyhow::Result<Vec<u8>> {
+    let output = tokio::process::Command::new("yt-dlp")
+        .args(args)
+        .output()
+        .await
+        .with_context(|| format!("spawning yt-dlp {args:?}"))?;
+    if !output.status.success() {
+        anyhow::bail!(
+            "yt-dlp {:?} exited {}: {}",
+            args,
+            output.status,
+            String::from_utf8_lossy(&output.stderr).trim()
+        );
+    }
+    Ok(output.stdout)
 }
diff --git a/sidecar/crates/torttube-sidecar/src/resolve.rs b/sidecar/crates/torttube-sidecar/src/resolve.rs
new file mode 100644
index 0000000..1aad439
--- /dev/null
+++ b/sidecar/crates/torttube-sidecar/src/resolve.rs
@@ -0,0 +1,146 @@
+// resolve.rs — Tier 1 (rustypipe) → Tier 2 (yt-dlp -j fallback)
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+use serde_json::Value;
+
+use crate::{run_yt_dlp, HandlerError};
+
+/// Top-level resolve. Tries Tier 1 (rustypipe), falls back to Tier 2 (yt-dlp -j).
+pub(crate) async fn resolve(id: &str) -> Result<Value, HandlerError> {
+    match tier1_rustypipe(id).await {
+        Ok(v) => {
+            tracing::info!(id, source = "rustypipe", "resolve ok");
+            Ok(v)
+        }
+        Err(e) => {
+            tracing::warn!(id, error = %e, "rustypipe failed; falling back to yt-dlp");
+            // Typed errors that mean "video can't be played by anyone" — don't retry yt-dlp,
+            // it'll just hit the same wall.
+            if matches!(
+                e,
+                HandlerError::AgeRestricted
+                    | HandlerError::PrivateVideo
+                    | HandlerError::NotFound
+            ) {
+                return Err(e);
+            }
+            tier2_yt_dlp(id).await
+        }
+    }
+}
+
+/// Tier 1 — native rustypipe. Serializes the whole player.details + selected streams as
+/// opaque pass-through JSON. The Python addon parses the fields it needs; this keeps us
+/// resilient to rustypipe shape evolution and unblocks tier-2 normalization later.
+async fn tier1_rustypipe(id: &str) -> Result<Value, HandlerError> {
+    use rustypipe::client::RustyPipe;
+    use rustypipe::param::StreamFilter;
+
+    let rp = RustyPipe::new();
+    let player = rp
+        .query()
+        .player(id)
+        .await
+        .map_err(|e| classify_rustypipe_error(&e))?;
+
+    let (video, audio) = player.select_video_audio_stream(&StreamFilter::default());
+
+    let details_json = serde_json::to_value(&player.details)
+        .map_err(|e| HandlerError::Internal(format!("serialize details: {e}")))?;
+    let video_json = video
+        .map(|v| serde_json::to_value(v))
+        .transpose()
+        .map_err(|e| HandlerError::Internal(format!("serialize video: {e}")))?
+        .unwrap_or(Value::Null);
+    let audio_json = audio
+        .map(|a| serde_json::to_value(a))
+        .transpose()
+        .map_err(|e| HandlerError::Internal(format!("serialize audio: {e}")))?
+        .unwrap_or(Value::Null);
+
+    Ok(serde_json::json!({
+        "source": "rustypipe",
+        "details": details_json,
+        "video_stream": video_json,
+        "audio_stream": audio_json,
+    }))
+}
+
+/// Classify a rustypipe error into one of our typed handler errors.
+/// rustypipe's error enum varies by version; we match on the Display string for resilience.
+fn classify_rustypipe_error(e: &dyn std::fmt::Display) -> HandlerError {
+    let msg = e.to_string().to_lowercase();
+    if msg.contains("age") && msg.contains("restrict") {
+        HandlerError::AgeRestricted
+    } else if msg.contains("region") || msg.contains("country") || msg.contains("geo") {
+        HandlerError::RegionBlocked
+    } else if msg.contains("private") {
+        HandlerError::PrivateVideo
+    } else if msg.contains("not found") || msg.contains("unavailable") {
+        HandlerError::NotFound
+    } else if msg.contains("network") || msg.contains("timeout") || msg.contains("connect") {
+        HandlerError::Network(msg)
+    } else {
+        HandlerError::Extractor(msg)
+    }
+}
+
+/// Tier 2 — shell out to yt-dlp -j.
+async fn tier2_yt_dlp(id: &str) -> Result<Value, HandlerError> {
+    let url = format!("https://www.youtube.com/watch?v={id}");
+    let stdout = run_yt_dlp(&["-j", "--no-warnings", "--no-playlist", &url])
+        .await
+        .map_err(|e| {
+            let msg = e.to_string().to_lowercase();
+            if msg.contains("age") {
+                HandlerError::AgeRestricted
+            } else if msg.contains("private") {
+                HandlerError::PrivateVideo
+            } else if msg.contains("not available") || msg.contains("does not exist") {
+                HandlerError::NotFound
+            } else if msg.contains("geo") || msg.contains("region") {
+                HandlerError::RegionBlocked
+            } else {
+                HandlerError::Extractor(msg)
+            }
+        })?;
+
+    let dump: Value = serde_json::from_slice(&stdout)
+        .map_err(|e| HandlerError::Extractor(format!("yt-dlp json parse: {e}")))?;
+
+    // yt-dlp's JSON has a `formats` array. We pass it through largely as-is — the addon
+    // can pick what inputstream.adaptive wants. Shape it to match our protocol.
+    let streams: Vec<Value> = dump
+        .get("formats")
+        .and_then(Value::as_array)
+        .cloned()
+        .unwrap_or_default()
+        .into_iter()
+        .filter_map(|f| {
+            let url = f.get("url")?.as_str()?.to_string();
+            let vcodec = f.get("vcodec").and_then(Value::as_str).unwrap_or("none");
+            let acodec = f.get("acodec").and_then(Value::as_str).unwrap_or("none");
+            let is_audio_only = vcodec == "none" && acodec != "none";
+            let is_video_only = vcodec != "none" && acodec == "none";
+            Some(serde_json::json!({
+                "url": url,
+                "itag": f.get("format_id").and_then(|v| v.as_str()).and_then(|s| s.parse::<u32>().ok()),
+                "mime": f.get("ext"),
+                "width": f.get("width"),
+                "height": f.get("height"),
+                "bitrate": f.get("tbr"),
+                "is_audio_only": is_audio_only,
+                "is_video_only": is_video_only,
+            }))
+        })
+        .collect();
+
+    Ok(serde_json::json!({
+        "source": "yt-dlp",
+        "title": dump.get("title"),
+        "duration_s": dump.get("duration"),
+        "channel_name": dump.get("channel"),
+        "channel_id": dump.get("channel_id"),
+        "streams": streams,
+    }))
+}
diff --git a/sidecar/crates/torttube-sidecar/src/rip.rs b/sidecar/crates/torttube-sidecar/src/rip.rs
new file mode 100644
index 0000000..0e2c29f
--- /dev/null
+++ b/sidecar/crates/torttube-sidecar/src/rip.rs
@@ -0,0 +1,61 @@
+// rip.rs — Tier 3: yt-dlp downloads the video to a local file, addon plays from disk.
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+// Last resort when stream URLs die mid-play (poToken expiry, cookie session mismatch,
+// HLS chunk 403s). Kodi can play partially-downloaded files, but for simplicity v0.1
+// waits for the full download to finish.
+
+use crate::{run_yt_dlp, HandlerError};
+use serde_json::Value;
+use std::path::Path;
+
+pub(crate) async fn rip(id: &str, dest_dir: &str) -> Result<Value, HandlerError> {
+    // Ensure dest dir exists.
+    tokio::fs::create_dir_all(dest_dir).await?;
+
+    let dest_dir = Path::new(dest_dir);
+    if !dest_dir.is_dir() {
+        return Err(HandlerError::Io(format!(
+            "dest_dir not a directory: {}",
+            dest_dir.display()
+        )));
+    }
+
+    // Use yt-dlp's output template so the resulting filename embeds the id we can grep for.
+    // -f bestvideo+bestaudio/best lets yt-dlp pick a mergable pair when possible.
+    let url = format!("https://www.youtube.com/watch?v={id}");
+    let output_template = dest_dir.join("%(id)s.%(ext)s");
+    let output_template_str = output_template.to_string_lossy().into_owned();
+
+    let stdout = run_yt_dlp(&[
+        "-o",
+        &output_template_str,
+        "-f",
+        "bestvideo+bestaudio/best",
+        "--no-playlist",
+        "--print",
+        "after_move:filepath",
+        &url,
+    ])
+    .await
+    .map_err(|e| HandlerError::Extractor(format!("yt-dlp rip: {e}")))?;
+
+    let file_path = String::from_utf8_lossy(&stdout).trim().to_string();
+    if file_path.is_empty() {
+        return Err(HandlerError::Extractor(
+            "yt-dlp rip: no filepath in output".to_string(),
+        ));
+    }
+
+    let meta = tokio::fs::metadata(&file_path).await.map_err(|e| {
+        HandlerError::Io(format!("stat ripped file {file_path}: {e}"))
+    })?;
+
+    tracing::info!(id, path = %file_path, size = meta.len(), "rip ok");
+
+    Ok(serde_json::json!({
+        "source": "yt-dlp-rip",
+        "path": file_path,
+        "size_bytes": meta.len(),
+    }))
+}
diff --git a/sidecar/crates/torttube-sidecar/src/sponsor.rs b/sidecar/crates/torttube-sidecar/src/sponsor.rs
new file mode 100644
index 0000000..3e828df
--- /dev/null
+++ b/sidecar/crates/torttube-sidecar/src/sponsor.rs
@@ -0,0 +1,115 @@
+// sponsor.rs — SponsorBlock client.
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+// Privacy-preserving lookup: SHA-256 the video ID, send the first 4 hex chars as a prefix,
+// SponsorBlock returns all segments for videos sharing that prefix; we filter locally.
+// Spec: https://wiki.sponsor.ajay.app/w/API_Docs#GET_/api/skipSegments/:sha256HashPrefix
+
+use serde::{Deserialize, Serialize};
+use sha2::{Digest, Sha256};
+
+const SPONSORBLOCK_API: &str = "https://sponsor.ajay.app/api/skipSegments";
+
+pub(crate) fn default_categories() -> Vec<String> {
+    vec!["sponsor".into(), "selfpromo".into(), "interaction".into()]
+}
+
+#[derive(Debug, Deserialize)]
+struct ApiResponse {
+    #[serde(rename = "videoID")]
+    video_id: String,
+    segments: Vec<ApiSegment>,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+struct ApiSegment {
+    #[serde(rename = "UUID")]
+    uuid: String,
+    segment: [f64; 2],
+    category: String,
+    #[serde(rename = "actionType")]
+    action_type: String,
+    #[serde(rename = "videoDuration", default)]
+    video_duration: f64,
+    #[serde(rename = "userID", default)]
+    user_id: String,
+    #[serde(default)]
+    votes: i32,
+    #[serde(default)]
+    locked: u8,
+    #[serde(default)]
+    description: String,
+}
+
+pub(crate) async fn fetch(id: &str, categories: &[String]) -> anyhow::Result<serde_json::Value> {
+    let prefix = hash_prefix(id, 4);
+    let categories_json = serde_json::to_string(categories)?;
+    let url = format!(
+        "{SPONSORBLOCK_API}/{prefix}?categories={enc}",
+        enc = urlencode(&categories_json)
+    );
+
+    let client = reqwest::Client::builder()
+        .user_agent(concat!("torttube-sidecar/", env!("CARGO_PKG_VERSION")))
+        .timeout(std::time::Duration::from_secs(10))
+        .build()?;
+
+    let resp = client.get(&url).send().await?;
+    if resp.status() == reqwest::StatusCode::NOT_FOUND {
+        // No segments matching the prefix at all.
+        return Ok(serde_json::json!({ "segments": [] }));
+    }
+    if !resp.status().is_success() {
+        anyhow::bail!("sponsorblock http {}", resp.status());
+    }
+
+    let body: Vec<ApiResponse> = resp.json().await?;
+
+    // Filter to the exact video id (the API returns all videos sharing the prefix).
+    let segments: Vec<&ApiSegment> = body
+        .iter()
+        .filter(|r| r.video_id == id)
+        .flat_map(|r| r.segments.iter())
+        .collect();
+
+    Ok(serde_json::json!({
+        "video_id": id,
+        "segments": segments,
+    }))
+}
+
+fn hash_prefix(id: &str, chars: usize) -> String {
+    let mut hasher = Sha256::new();
+    hasher.update(id.as_bytes());
+    let digest = hasher.finalize();
+    let hex_str = hex::encode(digest);
+    hex_str.chars().take(chars).collect()
+}
+
+/// Tiny URL-encoder for query parameter values. Only encodes characters that actually break
+/// query parsing — keeps the body readable in logs.
+fn urlencode(s: &str) -> String {
+    let mut out = String::with_capacity(s.len());
+    for b in s.bytes() {
+        match b {
+            b'A'..=b'Z' | b'a'..=b'z' | b'0'..=b'9' | b'-' | b'_' | b'.' | b'~' => {
+                out.push(b as char);
+            }
+            _ => out.push_str(&format!("%{:02X}", b)),
+        }
+    }
+    out
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn hash_prefix_known_value() {
+        // sha256("dQw4w9WgXcQ") starts with "9145..." — actually unknown, just verify shape.
+        let p = hash_prefix("dQw4w9WgXcQ", 4);
+        assert_eq!(p.len(), 4);
+        assert!(p.chars().all(|c| c.is_ascii_hexdigit()));
+    }
+}