diff --git a/CLAUDE.md b/CLAUDE.md
index c20d22d..57a493c 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -4,7 +4,7 @@ Local hybrid search CLI for Obsidian vaults. Rust, MIT licensed.
 
 ## Architecture
 
-Single binary with 13 modules behind a lib crate:
+Single binary with 14 modules behind a lib crate:
 
 - `config.rs` — loads `~/.engraph/config.toml` and `vault.toml`, merges CLI args, provides `data_dir()`
 - `chunker.rs` — smart chunking with break-point scoring algorithm. Finds optimal split points considering headings, code fences, blank lines, and thematic breaks. `split_oversized_chunks()` handles token-aware secondary splitting with overlap
@@ -14,13 +14,14 @@ Single binary with 13 modules behind a lib crate:
 - `fts.rs` — FTS5 full-text search support. Re-exports `FtsResult` from store. BM25-ranked keyword search
 - `fusion.rs` — Reciprocal Rank Fusion (RRF) engine. Merges semantic + FTS5 + graph results. Supports lane weighting, `--explain` output with per-lane detail
 - `context.rs` — context engine. Six functions: `read` (full note content + metadata), `list` (filtered note listing), `vault_map` (structure overview), `who` (person context bundle), `project` (project context bundle), `context_topic` (rich topic context with budget trimming). Pure functions taking `ContextParams` — no model loading except `context_topic` which reuses `search_internal`
+- `serve.rs` — MCP stdio server via rmcp SDK. Exposes 7 read-only tools (search, read, list, vault_map, who, project, context). EngraphServer struct with Arc+Mutex wrapping for async handlers. Loads all resources at startup.
 - `graph.rs` — vault graph agent. Extracts wikilink targets, expands search results by following graph connections 1-2 hops. Relevance filtering via FTS5 term check and shared tags
 - `profile.rs` — vault profile detection. Auto-detects PARA/Folders/Flat structure, vault type (Obsidian/Logseq/Plain), wikilinks, frontmatter, tags. Writes/loads `vault.toml`
 - `store.rs` — SQLite persistence. Tables: `meta`, `files` (with docid), `chunks` (with vector BLOBs), `chunks_fts` (FTS5), `edges` (vault graph), `tombstones`. Handles incremental diffing via content hashes
 - `hnsw.rs` — thin wrapper around `hnsw_rs`. **Important:** `hnsw_rs` does not support inserting after `load_hnsw()`. The index is rebuilt from vectors stored in SQLite on every index run
 - `indexer.rs` — orchestrates vault walking (via `ignore` crate for `.gitignore` support), diffing, chunking, embedding (Rayon for parallel chunking, serial embedding since `Embedder` is not `Send`), serial writes to store + HNSW + FTS5, and vault graph edge building (wikilinks + people detection)
 
-`main.rs` is a thin clap CLI. Subcommands: `index`, `search` (with `--explain`), `status`, `clear`, `init`, `configure`, `models`, `graph` (show/stats), `context` (read/list/vault-map/who/project/topic).
+`main.rs` is a thin clap CLI (async via `#[tokio::main]`). Subcommands: `index`, `search` (with `--explain`), `status`, `clear`, `init`, `configure`, `models`, `graph` (show/stats), `context` (read/list/vault-map/who/project/topic), `serve` (MCP stdio server).
 
 ## Key patterns
 
@@ -50,7 +51,7 @@ Single vault only. Re-indexing a different vault path triggers a confirmation pr
 
 ## Testing
 
-- Unit tests in each module (`cargo test --lib`) — 144 tests, no network required
+- Unit tests in each module (`cargo test --lib`) — 146 tests, no network required
 - 1 ignored smoke test (`test_embed_smoke`) — downloads ONNX model, verifies embedding
 - Integration tests (`cargo test --test integration -- --ignored`) — 8 tests, require model download
 
diff --git a/Cargo.lock b/Cargo.lock
index ee36be5..60f0716 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -37,6 +37,15 @@ version = "0.2.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "683d7910e743518b0e34f1186f92494becacb047c7b6bf616c96772180fef923"
 
+[[package]]
+name = "android_system_properties"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "819e7219dbd41043ac279b19830f2efc897156490d7fd6ea916720117ee66311"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "anndists"
 version = "0.1.4"
@@ -134,6 +143,17 @@ version = "1.0.102"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f202df86484c868dbad7eaa557ef785d5c66295e41b460ef922eca0723b842c"
 
+[[package]]
+name = "async-trait"
+version = "0.1.89"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9035ad2d096bed7955a320ee7e2230574d28fd3c3a0f186cbea1ff3c7eed5dbb"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.5.0"
@@ -256,6 +276,20 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
 
+[[package]]
+name = "chrono"
+version = "0.4.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c673075a2e0e5f4a1dde27ce9dee1ea4558c7ffe648f576438a20ca1d2acc4b0"
+dependencies = [
+ "iana-time-zone",
+ "js-sys",
+ "num-traits",
+ "serde",
+ "wasm-bindgen",
+ "windows-link",
+]
+
 [[package]]
 name = "clap"
 version = "4.6.0"
@@ -425,8 +459,18 @@ version = "0.20.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fc7f46116c46ff9ab3eb1597a45688b6715c6e628b5c133e288e709a29bcb4ee"
 dependencies = [
- "darling_core",
- "darling_macro",
+ "darling_core 0.20.11",
+ "darling_macro 0.20.11",
+]
+
+[[package]]
+name = "darling"
+version = "0.23.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "25ae13da2f202d56bd7f91c25fba009e7717a1e4a1cc98a76d844b65ae912e9d"
+dependencies = [
+ "darling_core 0.23.0",
+ "darling_macro 0.23.0",
 ]
 
 [[package]]
@@ -443,13 +487,37 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "darling_core"
+version = "0.23.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9865a50f7c335f53564bb694ef660825eb8610e0a53d3e11bf1b0d3df31e03b0"
+dependencies = [
+ "ident_case",
+ "proc-macro2",
+ "quote",
+ "strsim",
+ "syn",
+]
+
 [[package]]
 name = "darling_macro"
 version = "0.20.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fc34b93ccb385b40dc71c6fceac4b2ad23662c7eeb248cf10d529b7e055b6ead"
 dependencies = [
- "darling_core",
+ "darling_core 0.20.11",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "darling_macro"
+version = "0.23.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3984ec7bd6cfa798e62b4a642426a5be0e68f9401cfc2a01e3fa9ea2fcdb8d"
+dependencies = [
+ "darling_core 0.23.0",
  "quote",
  "syn",
 ]
@@ -488,7 +556,7 @@ version = "0.20.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2d5bcf7b024d6835cfb3d473887cd966994907effbe9227e8c8219824d06c4e8"
 dependencies = [
- "darling",
+ "darling 0.20.11",
  "proc-macro2",
  "quote",
  "syn",
@@ -546,6 +614,12 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "dyn-clone"
+version = "1.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d0881ea181b1df73ff77ffaaf9c7544ecc11e82fba9b5f27b262a3c73a332555"
+
 [[package]]
 name = "either"
 version = "1.15.0"
@@ -560,7 +634,7 @@ checksum = "34aa73646ffb006b8f5147f3dc182bd4bcb190227ce861fc4a4844bf8e3cb2c0"
 
 [[package]]
 name = "engraph"
-version = "0.3.0"
+version = "0.4.0"
 dependencies = [
  "anyhow",
  "clap",
@@ -571,12 +645,14 @@ dependencies = [
  "ndarray",
  "ort",
  "rayon",
+ "rmcp",
  "rusqlite",
  "serde",
  "serde_json",
  "sha2",
  "tempfile",
  "tokenizers",
+ "tokio",
  "toml",
  "tracing",
  "tracing-subscriber",
@@ -721,6 +797,94 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "futures"
+version = "0.3.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b147ee9d1f6d097cef9ce628cd2ee62288d963e16fb287bd9286455b241382d"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "futures-executor",
+ "futures-io",
+ "futures-sink",
+ "futures-task",
+ "futures-util",
+]
+
+[[package]]
+name = "futures-channel"
+version = "0.3.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "07bbe89c50d7a535e539b8c17bc0b49bdb77747034daa8087407d655f3f7cc1d"
+dependencies = [
+ "futures-core",
+ "futures-sink",
+]
+
+[[package]]
+name = "futures-core"
+version = "0.3.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7e3450815272ef58cec6d564423f6e755e25379b217b0bc688e295ba24df6b1d"
+
+[[package]]
+name = "futures-executor"
+version = "0.3.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf29c38818342a3b26b5b923639e7b1f4a61fc5e76102d4b1981c6dc7a7579d"
+dependencies = [
+ "futures-core",
+ "futures-task",
+ "futures-util",
+]
+
+[[package]]
+name = "futures-io"
+version = "0.3.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cecba35d7ad927e23624b22ad55235f2239cfa44fd10428eecbeba6d6a717718"
+
+[[package]]
+name = "futures-macro"
+version = "0.3.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e835b70203e41293343137df5c0664546da5745f82ec9b84d40be8336958447b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "futures-sink"
+version = "0.3.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c39754e157331b013978ec91992bde1ac089843443c49cbc7f46150b0fad0893"
+
+[[package]]
+name = "futures-task"
+version = "0.3.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "037711b3d59c33004d3856fbdc83b99d4ff37a24768fa1be9ce3538a1cde4393"
+
+[[package]]
+name = "futures-util"
+version = "0.3.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "389ca41296e6190b48053de0321d02a77f32f8a5d2461dd38762c0593805c6d6"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "futures-io",
+ "futures-macro",
+ "futures-sink",
+ "futures-task",
+ "memchr",
+ "pin-project-lite",
+ "slab",
+]
+
 [[package]]
 name = "generic-array"
 version = "0.14.7"
@@ -874,6 +1038,30 @@ version = "1.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6dbf3de79e51f3d586ab4cb9d5c3e2c14aa28ed23d180cf89b4df0454a69cc87"
 
+[[package]]
+name = "iana-time-zone"
+version = "0.1.65"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e31bc9ad994ba00e440a8aa5c9ef0ec67d5cb5e5cb0cc7f8b744a35b389cc470"
+dependencies = [
+ "android_system_properties",
+ "core-foundation-sys",
+ "iana-time-zone-haiku",
+ "js-sys",
+ "log",
+ "wasm-bindgen",
+ "windows-core",
+]
+
+[[package]]
+name = "iana-time-zone-haiku"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f31827a206f56af32e590ba56d5d2d085f558508192593743f16b2306495269f"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "icu_collections"
 version = "2.1.1"
@@ -1481,6 +1669,12 @@ version = "1.0.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
 
+[[package]]
+name = "pastey"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b867cad97c0791bbd3aaa6472142568c6c9e8f71937e98379f584cfb0cf35bec"
+
 [[package]]
 name = "pem-rfc7468"
 version = "0.7.0"
@@ -1667,6 +1861,26 @@ dependencies = [
  "thiserror 1.0.69",
 ]
 
+[[package]]
+name = "ref-cast"
+version = "1.0.25"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f354300ae66f76f1c85c5f84693f0ce81d747e2c3f21a45fef496d89c960bf7d"
+dependencies = [
+ "ref-cast-impl",
+]
+
+[[package]]
+name = "ref-cast-impl"
+version = "1.0.25"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b7186006dcb21920990093f30e3dea63b7d6e977bf1256be20c3563a5db070da"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "regex"
 version = "1.12.3"
@@ -1710,6 +1924,41 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "rmcp"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ba6b9d2f0efe2258b23767f1f9e0054cfbcac9c2d6f81a031214143096d7864f"
+dependencies = [
+ "async-trait",
+ "base64 0.22.1",
+ "chrono",
+ "futures",
+ "pastey",
+ "pin-project-lite",
+ "rmcp-macros",
+ "schemars",
+ "serde",
+ "serde_json",
+ "thiserror 2.0.18",
+ "tokio",
+ "tokio-util",
+ "tracing",
+]
+
+[[package]]
+name = "rmcp-macros"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab9d95d7ed26ad8306352b0d5f05b593222b272790564589790d210aa15caa9e"
+dependencies = [
+ "darling 0.23.0",
+ "proc-macro2",
+ "quote",
+ "serde_json",
+ "syn",
+]
+
 [[package]]
 name = "rusqlite"
 version = "0.32.1"
@@ -1802,6 +2051,32 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "schemars"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a2b42f36aa1cd011945615b92222f6bf73c599a102a300334cd7f8dbeec726cc"
+dependencies = [
+ "chrono",
+ "dyn-clone",
+ "ref-cast",
+ "schemars_derive",
+ "serde",
+ "serde_json",
+]
+
+[[package]]
+name = "schemars_derive"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d115b50f4aaeea07e79c1912f645c7513d81715d0420f8bc77a18c6260b307f"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "serde_derive_internals",
+ "syn",
+]
+
 [[package]]
 name = "scopeguard"
 version = "1.2.0"
@@ -1867,6 +2142,17 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "serde_derive_internals"
+version = "0.29.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "18d26a20a969b9e3fdf2fc2d9f21eda6c40e2de84c9408bb5d3b05d499aae711"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "serde_json"
 version = "1.0.149"
@@ -1921,6 +2207,12 @@ version = "0.3.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e320a6c5ad31d271ad523dcf3ad13e2767ad8b1cb8f047f75a8aeaf8da139da2"
 
+[[package]]
+name = "slab"
+version = "0.4.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0c790de23124f9ab44544d7ac05d60440adc586479ce501c1d6d7da3cd8c9cf5"
+
 [[package]]
 name = "smallvec"
 version = "1.15.1"
@@ -2115,6 +2407,41 @@ dependencies = [
  "unicode_categories",
 ]
 
+[[package]]
+name = "tokio"
+version = "1.50.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "27ad5e34374e03cfffefc301becb44e9dc3c17584f414349ebe29ed26661822d"
+dependencies = [
+ "bytes",
+ "pin-project-lite",
+ "tokio-macros",
+]
+
+[[package]]
+name = "tokio-macros"
+version = "2.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c55a2eff8b69ce66c84f85e1da1c233edc36ceb85a2058d11b0d6a3c7e7569c"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "tokio-util"
+version = "0.7.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ae9cec805b01e8fc3fd2fe289f89149a9b66dd16786abd8b19cfa7b48cb0098"
+dependencies = [
+ "bytes",
+ "futures-core",
+ "futures-sink",
+ "pin-project-lite",
+ "tokio",
+]
+
 [[package]]
 name = "toml"
 version = "0.8.23"
@@ -2558,12 +2885,65 @@ dependencies = [
  "windows-targets 0.48.5",
 ]
 
+[[package]]
+name = "windows-core"
+version = "0.62.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b8e83a14d34d0623b51dce9581199302a221863196a1dde71a7663a4c2be9deb"
+dependencies = [
+ "windows-implement",
+ "windows-interface",
+ "windows-link",
+ "windows-result",
+ "windows-strings",
+]
+
+[[package]]
+name = "windows-implement"
+version = "0.60.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "053e2e040ab57b9dc951b72c264860db7eb3b0200ba345b4e4c3b14f67855ddf"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "windows-interface"
+version = "0.59.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f316c4a2570ba26bbec722032c4099d8c8bc095efccdc15688708623367e358"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "windows-link"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
 
+[[package]]
+name = "windows-result"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7781fa89eaf60850ac3d2da7af8e5242a5ea78d1a11c49bf2910bb5a73853eb5"
+dependencies = [
+ "windows-link",
+]
+
+[[package]]
+name = "windows-strings"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7837d08f69c77cf6b07689544538e017c1bfcf57e34b4c0ff58e6c2cd3b37091"
+dependencies = [
+ "windows-link",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.48.0"
diff --git a/Cargo.toml b/Cargo.toml
index 46ad44a..90defef 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "engraph"
-version = "0.4.0"
+version = "0.5.0"
 edition = "2024"
 description = "Local semantic search for Obsidian vaults"
 license = "MIT"
@@ -24,6 +24,8 @@ ndarray = "0.17"
 hnsw_rs = "0.3"
 rayon = "1"
 ignore = "0.4"
+rmcp = { version = "1.2", features = ["transport-io"] }
+tokio = { version = "1", features = ["macros", "rt-multi-thread"] }
 
 [dev-dependencies]
 tempfile = "3"
diff --git a/src/lib.rs b/src/lib.rs
index c19dbe6..d48802a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -11,4 +11,5 @@ pub mod indexer;
 pub mod model;
 pub mod profile;
 pub mod search;
+pub mod serve;
 pub mod store;
diff --git a/src/main.rs b/src/main.rs
index d5ee073..013e585 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -82,6 +82,9 @@ enum Command {
         action: ModelsAction,
     },
 
+    /// Start MCP stdio server for AI agent access.
+    Serve,
+
     /// Inspect vault graph connections.
     Graph {
         #[command(subcommand)]
@@ -178,7 +181,8 @@ fn remove_dir_if_exists(path: &std::path::Path) -> Result<bool> {
     }
 }
 
-fn main() -> Result<()> {
+#[tokio::main]
+async fn main() -> Result<()> {
     let cli = Cli::parse();
 
     // Set up tracing. Default: suppress all logs (ort and hnsw_rs are very noisy).
@@ -704,6 +708,14 @@ fn main() -> Result<()> {
             }
         }
 
+        Command::Serve => {
+            if !index_exists(&data_dir) {
+                eprintln!("No index found. Run 'engraph index <path>' first.");
+                std::process::exit(1);
+            }
+            engraph::serve::run_serve(&data_dir).await?;
+        }
+
         Command::Models { action } => {
             let registry = model::ModelRegistry::default();
             match action {
diff --git a/src/search.rs b/src/search.rs
index 2746869..1ed0b92 100644
--- a/src/search.rs
+++ b/src/search.rs
@@ -20,7 +20,7 @@ pub struct SearchResult {
 }
 
 /// Structured search result for internal use (no I/O).
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, serde::Serialize)]
 pub struct InternalSearchResult {
     pub file_path: String,
     pub file_id: i64,
diff --git a/src/serve.rs b/src/serve.rs
new file mode 100644
index 0000000..97b57b7
--- /dev/null
+++ b/src/serve.rs
@@ -0,0 +1,276 @@
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+
+use anyhow::Result;
+use rmcp::handler::server::tool::ToolRouter;
+use rmcp::handler::server::wrapper::Parameters;
+use rmcp::model::{CallToolResult, Content, ServerCapabilities, ServerInfo};
+use rmcp::schemars;
+use rmcp::schemars::JsonSchema;
+use rmcp::{ErrorData as McpError, ServiceExt, tool, tool_handler, tool_router};
+use serde::Deserialize;
+use tokio::sync::Mutex;
+
+use crate::config::Config;
+use crate::context::{self, ContextParams};
+use crate::embedder::Embedder;
+use crate::hnsw::HnswIndex;
+use crate::profile::VaultProfile;
+use crate::search;
+use crate::store::Store;
+
+// ---------------------------------------------------------------------------
+// Parameter structs
+// ---------------------------------------------------------------------------
+
+#[derive(Debug, Deserialize, JsonSchema)]
+pub struct SearchParams {
+    /// The search query.
+    pub query: String,
+    /// Number of results (default 10).
+    pub top_n: Option<usize>,
+}
+
+#[derive(Debug, Deserialize, JsonSchema)]
+pub struct ReadParams {
+    /// File path, basename, or #docid.
+    pub file: String,
+}
+
+#[derive(Debug, Deserialize, JsonSchema)]
+pub struct ListParams {
+    /// Filter to folder path prefix.
+    pub folder: Option<String>,
+    /// Filter to notes with all listed tags.
+    pub tags: Option<Vec<String>>,
+    /// Maximum results (default 20).
+    pub limit: Option<usize>,
+}
+
+#[derive(Debug, Deserialize, JsonSchema)]
+pub struct WhoParams {
+    /// Person name (matches filename in People folder).
+    pub name: String,
+}
+
+#[derive(Debug, Deserialize, JsonSchema)]
+pub struct ProjectParams {
+    /// Project name (matches filename).
+    pub name: String,
+}
+
+#[derive(Debug, Deserialize, JsonSchema)]
+pub struct ContextToolParams {
+    /// Search query for the topic.
+    pub topic: String,
+    /// Character budget (default 32000).
+    pub budget: Option<usize>,
+}
+
+// ---------------------------------------------------------------------------
+// Server
+// ---------------------------------------------------------------------------
+
+#[derive(Clone)]
+pub struct EngraphServer {
+    store: Arc<Mutex<Store>>,
+    embedder: Arc<Mutex<Embedder>>,
+    hnsw_index: Arc<HnswIndex>,
+    vault_path: Arc<PathBuf>,
+    profile: Arc<Option<VaultProfile>>,
+    tool_router: ToolRouter<Self>,
+}
+
+fn mcp_err(e: &anyhow::Error) -> McpError {
+    McpError::new(
+        rmcp::model::ErrorCode::INTERNAL_ERROR,
+        format!("{e:#}"),
+        None::<serde_json::Value>,
+    )
+}
+
+fn to_json_result<T: serde::Serialize>(value: &T) -> Result<CallToolResult, McpError> {
+    let json = serde_json::to_string_pretty(value).map_err(|e| {
+        McpError::new(
+            rmcp::model::ErrorCode::INTERNAL_ERROR,
+            e.to_string(),
+            None::<serde_json::Value>,
+        )
+    })?;
+    Ok(CallToolResult::success(vec![Content::text(json)]))
+}
+
+#[tool_router]
+impl EngraphServer {
+    #[tool(
+        name = "search",
+        description = "Semantic + keyword hybrid search across the vault. Returns ranked results with file paths, scores, headings, and snippets."
+    )]
+    async fn search(&self, params: Parameters<SearchParams>) -> Result<CallToolResult, McpError> {
+        let top_n = params.0.top_n.unwrap_or(10);
+        let store = self.store.lock().await;
+        let mut embedder = self.embedder.lock().await;
+        let output = search::search_internal(
+            &params.0.query,
+            top_n,
+            &store,
+            &mut embedder,
+            &self.hnsw_index,
+        )
+        .map_err(|e| mcp_err(&e))?;
+        to_json_result(&output.results)
+    }
+
+    #[tool(
+        name = "read",
+        description = "Read a note's full content with metadata, tags, and graph edges. Accepts file path, basename, or #docid."
+    )]
+    async fn read(&self, params: Parameters<ReadParams>) -> Result<CallToolResult, McpError> {
+        let store = self.store.lock().await;
+        let ctx = ContextParams {
+            store: &store,
+            vault_path: &self.vault_path,
+            profile: self.profile.as_ref().as_ref(),
+        };
+        let note = context::context_read(&ctx, &params.0.file).map_err(|e| mcp_err(&e))?;
+        to_json_result(&note)
+    }
+
+    #[tool(
+        name = "list",
+        description = "List notes filtered by folder prefix and/or tags. Returns paths, docids, tags, and edge counts."
+    )]
+    async fn list(&self, params: Parameters<ListParams>) -> Result<CallToolResult, McpError> {
+        let store = self.store.lock().await;
+        let ctx = ContextParams {
+            store: &store,
+            vault_path: &self.vault_path,
+            profile: self.profile.as_ref().as_ref(),
+        };
+        let tags = params.0.tags.unwrap_or_default();
+        let limit = params.0.limit.unwrap_or(20);
+        let items = context::context_list(&ctx, params.0.folder.as_deref(), &tags, limit)
+            .map_err(|e| mcp_err(&e))?;
+        to_json_result(&items)
+    }
+
+    #[tool(
+        name = "vault_map",
+        description = "Vault structure overview: folders, tags, file counts, recent files. Use to orient before deeper queries."
+    )]
+    async fn vault_map(&self) -> Result<CallToolResult, McpError> {
+        let store = self.store.lock().await;
+        let ctx = ContextParams {
+            store: &store,
+            vault_path: &self.vault_path,
+            profile: self.profile.as_ref().as_ref(),
+        };
+        let map = context::vault_map(&ctx).map_err(|e| mcp_err(&e))?;
+        to_json_result(&map)
+    }
+
+    #[tool(
+        name = "who",
+        description = "Person context bundle: their note, mentions across the vault, and graph connections."
+    )]
+    async fn who(&self, params: Parameters<WhoParams>) -> Result<CallToolResult, McpError> {
+        let store = self.store.lock().await;
+        let ctx = ContextParams {
+            store: &store,
+            vault_path: &self.vault_path,
+            profile: self.profile.as_ref().as_ref(),
+        };
+        let person = context::context_who(&ctx, &params.0.name).map_err(|e| mcp_err(&e))?;
+        to_json_result(&person)
+    }
+
+    #[tool(
+        name = "project",
+        description = "Project context bundle: project note, child notes, active tasks, team members, and recent daily mentions."
+    )]
+    async fn project(&self, params: Parameters<ProjectParams>) -> Result<CallToolResult, McpError> {
+        let store = self.store.lock().await;
+        let ctx = ContextParams {
+            store: &store,
+            vault_path: &self.vault_path,
+            profile: self.profile.as_ref().as_ref(),
+        };
+        let proj = context::context_project(&ctx, &params.0.name).map_err(|e| mcp_err(&e))?;
+        to_json_result(&proj)
+    }
+
+    #[tool(
+        name = "context",
+        description = "Rich topic context with search-driven section selection and character budget trimming. Returns the most relevant note sections for a topic."
+    )]
+    async fn context(
+        &self,
+        params: Parameters<ContextToolParams>,
+    ) -> Result<CallToolResult, McpError> {
+        let budget = params.0.budget.unwrap_or(32000);
+        let store = self.store.lock().await;
+        let mut embedder = self.embedder.lock().await;
+        let ctx = ContextParams {
+            store: &store,
+            vault_path: &self.vault_path,
+            profile: self.profile.as_ref().as_ref(),
+        };
+        let bundle = context::context_topic_with_search(
+            &ctx,
+            &params.0.topic,
+            budget,
+            &mut embedder,
+            &self.hnsw_index,
+        )
+        .map_err(|e| mcp_err(&e))?;
+        to_json_result(&bundle)
+    }
+}
+
+#[tool_handler]
+impl rmcp::handler::server::ServerHandler for EngraphServer {
+    fn get_info(&self) -> ServerInfo {
+        ServerInfo::new(ServerCapabilities::builder().enable_tools().build()).with_instructions(
+            "engraph: vault intelligence for Obsidian. \
+                 Use vault_map to orient, search to find, \
+                 read for full content, who/project for context bundles.",
+        )
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Entry point
+// ---------------------------------------------------------------------------
+
+pub async fn run_serve(data_dir: &Path) -> Result<()> {
+    let db_path = data_dir.join("engraph.db");
+    let models_dir = data_dir.join("models");
+    let hnsw_dir = data_dir.join("hnsw");
+
+    let store = Store::open(&db_path)?;
+    let embedder = Embedder::new(&models_dir)?;
+    let hnsw_index = HnswIndex::load(&hnsw_dir)?;
+
+    let vault_path_str = store.get_meta("vault_path")?.ok_or_else(|| {
+        anyhow::anyhow!("No vault path in index. Run 'engraph index <path>' first.")
+    })?;
+    let vault_path = PathBuf::from(&vault_path_str);
+
+    let profile = Config::load_vault_profile().ok().flatten();
+
+    let server = EngraphServer {
+        store: Arc::new(Mutex::new(store)),
+        embedder: Arc::new(Mutex::new(embedder)),
+        hnsw_index: Arc::new(hnsw_index),
+        vault_path: Arc::new(vault_path),
+        profile: Arc::new(profile),
+        tool_router: EngraphServer::tool_router(),
+    };
+
+    eprintln!("engraph MCP server starting...");
+
+    let transport = rmcp::transport::io::stdio();
+    let server_handle = server.serve(transport).await?;
+    server_handle.waiting().await?;
+    Ok(())
+}