From 3873fad612eef27e5b88841b6ea097b59eb8ea70 Mon Sep 17 00:00:00 2001
From: Joakim Hulthe <joakim@hulthe.net>
Date: Fri, 21 Aug 2026 22:54:12 +0200
Subject: [PATCH] Add MCP server

---
 Cargo.lock      | 289 +++++++++++++++++++++++++++++++++++++++++++++++-
 srv/Cargo.toml  |   5 +-
 srv/src/main.rs |  20 ++++
 srv/src/mcp.rs  |  89 +++++++++++++++
 4 files changed, 398 insertions(+), 5 deletions(-)
 create mode 100644 srv/src/mcp.rs

diff --git a/Cargo.lock b/Cargo.lock
index c60de8b..1364e5a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -419,7 +419,7 @@ dependencies = [
  "log",
  "num-rational",
  "num-traits",
- "pastey",
+ "pastey 0.1.1",
  "rayon",
  "thiserror 2.0.20",
  "v_frame",
@@ -507,6 +507,12 @@ version = "0.22.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "72b3254f16251a8381aa12e40e3c4d2f0199f8c6508fbecb9d91f575e0fbb8c6"
 
+[[package]]
+name = "base64"
+version = "0.23.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac07cdecf99051d9a5238b80f35af32cdeba5b336e55d957b318b50137e18da5"
+
 [[package]]
 name = "bincode"
 version = "2.0.1"
@@ -777,6 +783,7 @@ dependencies = [
  "iana-time-zone",
  "js-sys",
  "num-traits",
+ "serde",
  "wasm-bindgen",
  "windows-link",
 ]
@@ -1066,6 +1073,40 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f27ae1dd37df86211c42e150270f82743308803d90a6f6e6651cd730d5e1732f"
 
+[[package]]
+name = "darling"
+version = "0.24.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed17f5901b6630b993ca003def43f2f8ef4014fc13b047b57aad617ff32bc2ec"
+dependencies = [
+ "darling_core",
+ "darling_macro",
+]
+
+[[package]]
+name = "darling_core"
+version = "0.24.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6837e2cf7485aaae18f86181d2f0e9a7ed297a025e220aeabf63fdebd3a2ddff"
+dependencies = [
+ "ident_case",
+ "proc-macro2",
+ "quote",
+ "strsim",
+ "syn 3.0.3",
+]
+
+[[package]]
+name = "darling_macro"
+version = "0.24.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2ac7135c3ef02b2f7833bbeb1be5ba7f966dcde8a87c6b87f65a778d71a02785"
+dependencies = [
+ "darling_core",
+ "quote",
+ "syn 3.0.3",
+]
+
 [[package]]
 name = "data-url"
 version = "0.3.2"
@@ -1194,6 +1235,12 @@ dependencies = [
  "linux-raw-sys 0.9.4",
 ]
 
+[[package]]
+name = "dyn-clone"
+version = "1.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d0881ea181b1df73ff77ffaaf9c7544ecc11e82fba9b5f27b262a3c73a332555"
+
 [[package]]
 name = "either"
 version = "1.17.0"
@@ -1785,6 +1832,25 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b40ca9252762c466af32d0b1002e91e4e1bc5398f77455e55474deb466355ff5"
 
+[[package]]
+name = "h2"
+version = "0.4.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a9f37a958b41b3b19ee2707c06439c0e9e547e847223eb791ecb0cb821c65e27"
+dependencies = [
+ "atomic-waker",
+ "bytes",
+ "fnv",
+ "futures-core",
+ "futures-sink",
+ "http",
+ "indexmap",
+ "slab",
+ "tokio",
+ "tokio-util",
+ "tracing",
+]
+
 [[package]]
 name = "half"
 version = "2.7.1"
@@ -1925,6 +1991,7 @@ dependencies = [
  "bytes",
  "futures-channel",
  "futures-core",
+ "h2",
  "http",
  "http-body",
  "httparse",
@@ -1958,7 +2025,7 @@ version = "0.1.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "96547c2556ec9d12fb1578c4eaf448b04993e7fb79cbaad930a656880a6bdfa0"
 dependencies = [
- "base64",
+ "base64 0.22.1",
  "bytes",
  "futures-channel",
  "futures-util",
@@ -2480,6 +2547,12 @@ version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e4a2c462a4d927d512f5f882a033ddd62f33a05bb9f230d98f736ac3dc85938f"
 
+[[package]]
+name = "ident_case"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9e0384b61958566e926dc50660321d12159025e767c18e043daf26b70104c39"
+
 [[package]]
 name = "idna"
 version = "1.1.0"
@@ -2589,11 +2662,14 @@ dependencies = [
  "axum",
  "clap",
  "inkopslista-lib",
+ "rmcp",
  "serde",
  "serde_json",
  "sqlite",
  "tokio",
  "tower-http 0.7.0",
+ "tracing",
+ "tracing-subscriber",
 ]
 
 [[package]]
@@ -3028,6 +3104,15 @@ dependencies = [
  "num-traits",
 ]
 
+[[package]]
+name = "matchers"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d1525a2a28c7f4fa0fc98bb91ae755d1e2d1505079e05539e35bc876b5d65ae9"
+dependencies = [
+ "regex-automata",
+]
+
 [[package]]
 name = "matchit"
 version = "0.8.4"
@@ -3278,6 +3363,15 @@ dependencies = [
  "bitflags 2.13.1",
 ]
 
+[[package]]
+name = "nu-ansi-term"
+version = "0.50.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7957b9740744892f114936ab4a57b3f487491bbeafaf8083688b16841a4240e5"
+dependencies = [
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "num-bigint"
 version = "0.4.8"
@@ -3855,6 +3949,12 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "35fb2e5f958ec131621fdd531e9fc186ed768cbe395337403ae56c17a74c68ec"
 
+[[package]]
+name = "pastey"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2ee67f1008b1ba2321834326597b8e186293b049a023cdef258527550b9935b4"
+
 [[package]]
 name = "percent-encoding"
 version = "2.3.2"
@@ -4395,6 +4495,26 @@ dependencies = [
  "bitflags 2.13.1",
 ]
 
+[[package]]
+name = "ref-cast"
+version = "1.0.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7e440fb4e4b4147295338efb76001ab9e4efc0e5839df2c47fc5ac2381d365c3"
+dependencies = [
+ "ref-cast-impl",
+]
+
+[[package]]
+name = "ref-cast-impl"
+version = "1.0.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "92ecd8964f8453721699a1ed72037b0db49ce2f5a5138486ee89bed6f67cdf3a"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 3.0.3",
+]
+
 [[package]]
 name = "regex"
 version = "1.13.1"
@@ -4430,7 +4550,7 @@ version = "0.12.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "eddd3ca559203180a307f12d114c268abf583f59b03cb906fd0b3ff8646c1147"
 dependencies = [
- "base64",
+ "base64 0.22.1",
  "bytes",
  "futures-core",
  "http",
@@ -4502,6 +4622,50 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "rmcp"
+version = "3.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c8dddc5b1924b9a59fba420166160ca2c4663a4e01803e52eda33070f56d63c8"
+dependencies = [
+ "async-trait",
+ "base64 0.23.1",
+ "bytes",
+ "chrono",
+ "futures",
+ "http",
+ "http-body",
+ "http-body-util",
+ "pastey 0.2.3",
+ "pin-project-lite",
+ "rand 0.10.2",
+ "rmcp-macros",
+ "schemars",
+ "serde",
+ "serde_json",
+ "sse-stream",
+ "thiserror 2.0.20",
+ "tokio",
+ "tokio-stream",
+ "tokio-util",
+ "tower-service",
+ "tracing",
+ "uuid",
+]
+
+[[package]]
+name = "rmcp-macros"
+version = "3.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a85d45508e9b4ba024fe996c2638799635d75b6dd0ba8f32ccf08f8026f0c780"
+dependencies = [
+ "darling",
+ "proc-macro2",
+ "quote",
+ "serde_json",
+ "syn 3.0.3",
+]
+
 [[package]]
 name = "rowan"
 version = "0.16.1"
@@ -4657,6 +4821,32 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "schemars"
+version = "1.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "687274d293b6cdc6e73e0fee520bf2049650090d7164f87672d212a3c530cf4a"
+dependencies = [
+ "chrono",
+ "dyn-clone",
+ "ref-cast",
+ "schemars_derive",
+ "serde",
+ "serde_json",
+]
+
+[[package]]
+name = "schemars_derive"
+version = "1.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d98c67716b46af2f0b8cf752abc930f6f9aecfbf671ecfb531db8a31dbe4e2ba"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "serde_derive_internals",
+ "syn 3.0.3",
+]
+
 [[package]]
 name = "scoped-tls"
 version = "1.0.1"
@@ -4724,6 +4914,17 @@ dependencies = [
  "syn 3.0.3",
 ]
 
+[[package]]
+name = "serde_derive_internals"
+version = "0.30.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f852137cce035d6a4df67ccce505ff6b3e9fd3a10e3e52b24dc71e650bb1a9bd"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 3.0.3",
+]
+
 [[package]]
 name = "serde_json"
 version = "1.0.151"
@@ -4780,6 +4981,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "sharded-slab"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f40ca3c46823713e0d4209592e8d6e826aa57e928f09752619fc696c499637f6"
+dependencies = [
+ "lazy_static",
+]
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
@@ -5166,6 +5376,19 @@ dependencies = [
  "sqlite3-src",
 ]
 
+[[package]]
+name = "sse-stream"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c123f296ade4ec4b8b0f6162116e6629f5146922ca5ab40ca9d3c2e73ab4761e"
+dependencies = [
+ "bytes",
+ "futures-util",
+ "http-body",
+ "http-body-util",
+ "pin-project-lite",
+]
+
 [[package]]
 name = "stable_deref_trait"
 version = "1.2.1"
@@ -5371,6 +5594,15 @@ dependencies = [
  "syn 3.0.3",
 ]
 
+[[package]]
+name = "thread_local"
+version = "1.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ad99c4c6d32803332c548b1af0540b357b3f5fc0be8f6c6bfe8b2e6ae784070"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "tiff"
 version = "0.11.3"
@@ -5500,6 +5732,17 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "tokio-stream"
+version = "0.1.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a3d06f0b082ba57c26b79407372e57cf2a1e28124f78e9479fe80322cf53420b"
+dependencies = [
+ "futures-core",
+ "pin-project-lite",
+ "tokio",
+]
+
 [[package]]
 name = "tokio-util"
 version = "0.7.19"
@@ -5509,6 +5752,7 @@ dependencies = [
  "bytes",
  "futures-core",
  "futures-sink",
+ "libc",
  "pin-project-lite",
  "tokio",
 ]
@@ -5668,6 +5912,36 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "db97caf9d906fbde555dd62fa95ddba9eecfd14cb388e4f491a66d74cd5fb79a"
 dependencies = [
  "once_cell",
+ "valuable",
+]
+
+[[package]]
+name = "tracing-log"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee855f1f400bd0e5c02d150ae5de3840039a3f54b025156404e34c23c03f47c3"
+dependencies = [
+ "log",
+ "once_cell",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-subscriber"
+version = "0.3.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cb7f578e5945fb242538965c2d0b04418d38ec25c79d160cd279bf0731c8d319"
+dependencies = [
+ "matchers",
+ "nu-ansi-term",
+ "once_cell",
+ "regex-automata",
+ "sharded-slab",
+ "smallvec",
+ "thread_local",
+ "tracing",
+ "tracing-core",
+ "tracing-log",
 ]
 
 [[package]]
@@ -5820,7 +6094,7 @@ version = "0.47.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d46cf96c5f498d36b7a9693bc6a7075c0bb9303189d61b2249b0dc3d309c07de"
 dependencies = [
- "base64",
+ "base64 0.22.1",
  "data-url",
  "flate2",
  "fontdb",
@@ -5860,6 +6134,7 @@ version = "1.24.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bf3923a6f5c4c6382e0b653c4117f48d631ea17f38ed86e2a828e6f7412f5239"
 dependencies = [
+ "getrandom 0.4.3",
  "js-sys",
  "serde_core",
  "wasm-bindgen",
@@ -5876,6 +6151,12 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "valuable"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ba73ea9cf16a25df0c8caa16c51acb937d5712a8429db78a3ee29d5dcacd3a65"
+
 [[package]]
 name = "version_check"
 version = "0.9.5"
diff --git a/srv/Cargo.toml b/srv/Cargo.toml
index 66e6512..ddef10c 100644
--- a/srv/Cargo.toml
+++ b/srv/Cargo.toml
@@ -9,6 +9,9 @@ serde_json = "1.0.145"
 inkopslista-lib = { path = "../lib" }
 sqlite = "0.37.0"
 clap = { version = "4.6.6", features = ["derive", "env"] }
-axum = { version = "0.8.9", features = ["http1"] }
+axum = { version = "0.8.9", features = ["http1", "http2", "tokio"] }
 tower-http = { version = "0.7.0", features = ["fs", "trace", "compression-gzip"] }
 tokio = { version = "1.53.1", features = ["full"] }
+rmcp = { version = "3.1.2", features = ["server", "macros", "schemars", "transport-streamable-http-server", "transport-streamable-http-server-session"] }
+tracing = "0.1.44"
+tracing-subscriber = { version = "0.3.23", features = ["env-filter"] }
diff --git a/srv/src/main.rs b/srv/src/main.rs
index ae0af06..d7b81e8 100644
--- a/srv/src/main.rs
+++ b/srv/src/main.rs
@@ -9,6 +9,10 @@ use std::net::SocketAddr;
 use std::path::PathBuf;
 use std::sync::Arc;
 use tower_http::services::ServeDir;
+use tower_http::trace::TraceLayer;
+use tracing::Level;
+
+mod mcp;
 
 /// The directory where the web files for the gui is stored.
 fn www_path() -> &'static std::path::Path {
@@ -116,6 +120,8 @@ struct Opt {
     bind: SocketAddr,
     #[clap(long, env = "DB_PATH")]
     db_path: PathBuf,
+    #[clap(long, env = "RUST_LOG", default_value = "debug")]
+    log_level: String,
     #[clap(long, env = "NUM_DAYS", default_value = "5")]
     num_days: u32,
 }
@@ -123,6 +129,11 @@ struct Opt {
 #[tokio::main]
 async fn main() {
     let opt = Opt::parse();
+
+    tracing_subscriber::fmt()
+        .with_env_filter(tracing_subscriber::EnvFilter::new(&opt.log_level))
+        .init();
+
     let db = sqlite::Connection::open_thread_safe(opt.db_path).unwrap();
     db.execute(include_str!("db/init.sql"))
         .expect("unable to initialize database");
@@ -135,8 +146,17 @@ async fn main() {
         .route("/api/favorites", get(get_favorites))
         .route("/api/favorites/{item}/category", put(put_category))
         .fallback_service(ServeDir::new(www_path()))
+        .nest_service("/mcp", mcp::service(db.clone()))
+        .layer(
+            TraceLayer::new_for_http()
+                .make_span_with(tower_http::trace::DefaultMakeSpan::new().level(Level::INFO))
+                .on_request(tower_http::trace::DefaultOnRequest::new().level(Level::INFO))
+                .on_response(tower_http::trace::DefaultOnResponse::new().level(Level::INFO)),
+        )
         .with_state(db);
 
     let listener = tokio::net::TcpListener::bind(opt.bind).await.unwrap();
+    tracing::info!("Listening on http://{}", opt.bind);
+
     axum::serve(listener, app).await.unwrap();
 }
diff --git a/srv/src/mcp.rs b/srv/src/mcp.rs
new file mode 100644
index 0000000..a95caaf
--- /dev/null
+++ b/srv/src/mcp.rs
@@ -0,0 +1,89 @@
+//! MCP routes
+
+use axum::Json;
+use axum::extract::{Path, State};
+use inkopslista_lib::ItemData;
+use rmcp::handler::server::wrapper::Parameters;
+use rmcp::transport::streamable_http_server::session::local::LocalSessionManager;
+use rmcp::transport::streamable_http_server::tower::{
+    StreamableHttpServerConfig, StreamableHttpService,
+};
+use rmcp::{schemars, tool, tool_router};
+use serde::Deserialize;
+use sqlite::ConnectionThreadSafe;
+use std::fmt::Write;
+use std::sync::Arc;
+
+#[derive(Debug, Deserialize, schemars::JsonSchema)]
+struct PutParams {
+    /// The name of the shopping-list item,
+    item: String,
+    /// The number of items to buy.
+    #[serde(default = "default_amount")]
+    amount: i64,
+    /// Whether the item has been checked off.
+    #[serde(default)]
+    checked: bool,
+}
+
+fn default_amount() -> i64 {
+    1
+}
+
+#[derive(Clone)]
+pub struct McpServer {
+    db: Arc<ConnectionThreadSafe>,
+}
+
+#[tool_router(server_handler)]
+impl McpServer {
+    #[tool(description = "Read the entire shopping list")]
+    async fn list(&self) -> String {
+        // TODO: don't call the HTTP request handlers. Split the DB stuff out instead.
+        let db = State(self.db.clone());
+        let items = crate::get_list(db).await.0;
+        let mut out = String::new();
+        for item in items {
+            _ = writeln!(
+                &mut out,
+                "- [{checked}] {n}x {name}",
+                checked = if item.data.checked { "x" } else { " " },
+                n = item.data.amount,
+                name = item.name,
+            );
+        }
+        out
+    }
+
+    #[tool(description = "Put an item onto the shopping list.")]
+    async fn put(&self, Parameters(params): Parameters<PutParams>) -> String {
+        // TODO: don't call the HTTP request handlers. Split the DB stuff out instead.
+        let db = State(self.db.clone());
+        let data = ItemData {
+            amount: params.amount,
+            checked: params.checked,
+        };
+        crate::put_list(db, Path(params.item), Json(data)).await;
+        "Ok".to_string()
+    }
+}
+
+/// Create an MCP service that can be plugged into axum
+pub fn service(
+    db: Arc<ConnectionThreadSafe>,
+) -> StreamableHttpService<McpServer, LocalSessionManager> {
+    // TODO: tower_http::auth::add_authorization
+    let config = StreamableHttpServerConfig::default()
+        .with_legacy_session_mode(true)
+        .with_json_response(false)
+        .disable_allowed_hosts()
+        .disable_allowed_origins();
+
+    let server = McpServer { db };
+
+    StreamableHttpService::new(
+        move || Ok(server.clone()),
+        LocalSessionManager::default().into(),
+        config,
+    )
+}