agent: embedded MCP server (rmcp) with send/recv tools

CLAUDE.md

@@ -156,6 +156,20 @@ docs/damocles-migration.md   options for moving damocles onto hyperhive
   marks them `failed` with note `"agent state dir missing"` so they fall out
   of `pending`. They stay in sqlite for audit.
 
+## Agent MCP surface
+
+The harness ships an embedded MCP server (rmcp 1.7) that claude can launch
+via `--mcp-config`. Subcommand: `hive-ag3nt mcp`. Tools:
+- `send(to, body)` — message a peer or the operator.
+- `recv()` — drain one inbox message.
+
+Both translate to `AgentRequest::Send`/`Recv` against the agent's own
+`/run/hive/mcp.sock` (the existing hyperhive socket). The MCP surface is
+just claude's view of that socket — same authority, friendlier protocol.
+
+Manager will get its own subcommand later with `request_spawn`, `kill`,
+`request_apply_commit` added to the TOOLS list.
+
 ## Manager (hm1nd) is hive-c0re-managed
 
 The manager container runs through the **same lifecycle as sub-agents** —

Cargo.lock

@@ -11,6 +11,15 @@ dependencies = [
  "memchr",
 ]
 
+[[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 = "anstream"
 version = "1.0.0"
@@ -67,12 +76,29 @@ 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 = "atomic-waker"
 version = "1.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1505bd5d3d116872e7271a6d4e16d81d0c8570876c8de68093a09ac269d8aac0"
 
+[[package]]
+name = "autocfg"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c08606f8c3cbf4ce6ec8e28fb0014a2c086708fe954eaa885384a6165172e7e8"
+
 [[package]]
 name = "axum"
 version = "0.8.9"
@@ -131,6 +157,12 @@ version = "2.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c4512299f36f043ab09a583e57bceb5a5aab7a73db1805848e8fef3c9e8c78b3"
 
+[[package]]
+name = "bumpalo"
+version = "3.20.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5d20789868f4b01b2f2caec9f5c4e0213b41e3e5702a50157d699ae31ced2fcb"
+
 [[package]]
 name = "bytes"
 version = "1.11.1"
@@ -153,6 +185,18 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
+[[package]]
+name = "chrono"
+version = "0.4.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c673075a2e0e5f4a1dde27ce9dee1ea4558c7ffe648f576438a20ca1d2acc4b0"
+dependencies = [
+ "iana-time-zone",
+ "num-traits",
+ "serde",
+ "windows-link",
+]
+
 [[package]]
 name = "clap"
 version = "4.6.1"
@@ -199,6 +243,52 @@ version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1d07550c9036bf2ae0c684c4297d503f838287c83c53686d05370d0e139ae570"
 
+[[package]]
+name = "core-foundation-sys"
+version = "0.8.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "773648b94d0e5d620f64f280777445740e61fe701025087ec8b57f45c791888b"
+
+[[package]]
+name = "darling"
+version = "0.23.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "25ae13da2f202d56bd7f91c25fba009e7717a1e4a1cc98a76d844b65ae912e9d"
+dependencies = [
+ "darling_core",
+ "darling_macro",
+]
+
+[[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 = "0.23.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3984ec7bd6cfa798e62b4a642426a5be0e68f9401cfc2a01e3fa9ea2fcdb8d"
+dependencies = [
+ "darling_core",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "dyn-clone"
+version = "1.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d0881ea181b1df73ff77ffaaf9c7544ecc11e82fba9b5f27b262a3c73a332555"
+
 [[package]]
 name = "errno"
 version = "0.3.14"
@@ -242,6 +332,21 @@ 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"
@@ -249,6 +354,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "07bbe89c50d7a535e539b8c17bc0b49bdb77747034daa8087407d655f3f7cc1d"
 dependencies = [
  "futures-core",
+ "futures-sink",
 ]
 
 [[package]]
@@ -257,6 +363,34 @@ 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"
@@ -275,8 +409,13 @@ 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",
 ]
@@ -313,6 +452,8 @@ dependencies = [
  "axum",
  "clap",
  "hive-sh4re",
+ "rmcp",
+ "schemars",
  "serde",
  "serde_json",
  "tokio",
@@ -425,6 +566,36 @@ dependencies = [
  "tower-service",
 ]
 
+[[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 = "ident_case"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9e0384b61958566e926dc50660321d12159025e767c18e043daf26b70104c39"
+
 [[package]]
 name = "is_terminal_polyfill"
 version = "1.70.2"
@@ -437,6 +608,18 @@ version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8f42a60cbdf9a97f5d2305f08a87dc4e09308d1276d28c869c684d7777685682"
 
+[[package]]
+name = "js-sys"
+version = "0.3.98"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67df7112613f8bfd9150013a0314e196f4800d3201ae742489d999db2f979f08"
+dependencies = [
+ "cfg-if",
+ "futures-util",
+ "once_cell",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.5.0"
@@ -513,6 +696,15 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "num-traits"
+version = "0.2.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.21.4"
@@ -525,6 +717,12 @@ version = "1.70.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "384b8ab6d37215f3c5301a95a4accb5d64aa607f1fcb26a11b5303878451b4fe"
 
+[[package]]
+name = "pastey"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c5a797f0e07bdf071d15742978fc3128ec6c22891c31a3a931513263904c982a"
+
 [[package]]
 name = "percent-encoding"
 version = "2.3.2"
@@ -561,6 +759,26 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[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-automata"
 version = "0.4.14"
@@ -578,6 +796,40 @@ version = "0.8.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc897dd8d9e8bd1ed8cdad82b5966c3e0ecae09fb1907d58efaa013543185d0a"
 
+[[package]]
+name = "rmcp"
+version = "1.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0810a9f717d9828f475fe1f629f4c305c8464b7f496c3a854b58d29e65f4058e"
+dependencies = [
+ "async-trait",
+ "chrono",
+ "futures",
+ "pastey",
+ "pin-project-lite",
+ "rmcp-macros",
+ "schemars",
+ "serde",
+ "serde_json",
+ "thiserror",
+ "tokio",
+ "tokio-util",
+ "tracing",
+]
+
+[[package]]
+name = "rmcp-macros"
+version = "1.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6aefac48c364756e97f04c0401ba3231e8607882c7c1d92da0437dc16307904d"
+dependencies = [
+ "darling",
+ "proc-macro2",
+ "quote",
+ "serde_json",
+ "syn",
+]
+
 [[package]]
 name = "rusqlite"
 version = "0.37.0"
@@ -592,12 +844,44 @@ dependencies = [
  "smallvec",
 ]
 
+[[package]]
+name = "rustversion"
+version = "1.0.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b39cdef0fa800fc44525c84ccb54a029961a8215f9619753635a9c0d2538d46d"
+
 [[package]]
 name = "ryu"
 version = "1.0.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9774ba4a74de5f7b1c1451ed6cd5285a32eddb5cccb8cc655a4e50009e06477f"
 
+[[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 = "serde"
 version = "1.0.228"
@@ -628,6 +912,17 @@ 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"
@@ -740,6 +1035,26 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0bf256ce5efdfa370213c1dabab5935a12e49f2c58d15e9eac2870d3b4f27263"
 
+[[package]]
+name = "thiserror"
+version = "2.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4288b5bcbc7920c07a1149a35cf9590a2aa808e0bc1eafaade0b80947865fbc4"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "2.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ebc4ee7f67670e9b64d05fa4253e753e016c6c95ff35b89b7941d6b856dec1d5"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "thread_local"
 version = "1.1.9"
@@ -921,12 +1236,110 @@ version = "0.11.1+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ccf3ec651a847eb01de73ccad15eb7d99f80485de043efb2f370cd654f4ea44b"
 
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.121"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49ace1d07c165b0864824eee619580c4689389afa9dc9ed3a4c75040d82e6790"
+dependencies = [
+ "cfg-if",
+ "once_cell",
+ "rustversion",
+ "wasm-bindgen-macro",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.121"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e68e6f4afd367a562002c05637acb8578ff2dea1943df76afb9e83d177c8578"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.121"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d95a9ec35c64b2a7cb35d3fead40c4238d0940c86d107136999567a4703259f2"
+dependencies = [
+ "bumpalo",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.121"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4e0100b01e9f0d03189a92b96772a1fb998639d981193d7dbab487302513441"
+dependencies = [
+ "unicode-ident",
+]
+
+[[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 = "0.61.2"

Cargo.toml

@@ -19,7 +19,13 @@ anyhow = "1"
 axum = "0.8"
 clap = { version = "4", features = ["derive"] }
 hive-sh4re = { path = "hive-sh4re" }
+rmcp = { version = "1.7", default-features = false, features = [
+  "server",
+  "macros",
+  "transport-io",
+] }
 rusqlite = { version = "0.37", features = ["bundled"] }
+schemars = "1.0"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 similar = "2"

hive-ag3nt/Cargo.toml

@@ -11,6 +11,8 @@ anyhow.workspace = true
 axum.workspace = true
 clap.workspace = true
 hive-sh4re.workspace = true
+rmcp.workspace = true
+schemars.workspace = true
 serde.workspace = true
 serde_json.workspace = true
 tokio.workspace = true

hive-ag3nt/src/bin/hive-ag3nt.rs

@@ -5,7 +5,7 @@ use std::time::Duration;
 use anyhow::{Result, bail};
 use clap::{Parser, Subcommand};
 use hive_ag3nt::login::{self, LoginState};
-use hive_ag3nt::{DEFAULT_SOCKET, DEFAULT_WEB_PORT, client, web_ui};
+use hive_ag3nt::{DEFAULT_SOCKET, DEFAULT_WEB_PORT, client, mcp, web_ui};
 use hive_sh4re::{AgentRequest, AgentResponse};
 use tokio::process::Command;
 
@@ -33,6 +33,10 @@ enum Cmd {
     Send { to: String, body: String },
     /// Pop one message from the inbox.
     Recv,
+    /// Run the agent's MCP server on stdio. Spawned by `claude` via
+    /// `--mcp-config`; tools dispatch through `/run/hive/mcp.sock` back into
+    /// the hyperhive broker.
+    Mcp,
 }
 
 #[tokio::main]
@@ -88,6 +92,7 @@ async fn main() -> Result<()> {
             render(&resp)?;
             check(&resp)
         }
+        Cmd::Mcp => mcp::serve_stdio(cli.socket).await,
     }
 }
 

hive-ag3nt/src/lib.rs

@@ -4,6 +4,7 @@
 pub mod client;
 pub mod login;
 pub mod login_session;
+pub mod mcp;
 pub mod web_ui;
 
 /// Default socket path inside the container — bind-mounted by `hive-c0re`.

hive-ag3nt/src/mcp.rs

@@ -0,0 +1,103 @@
+//! Embedded MCP server. Claude Code (running inside the agent container)
+//! launches this as a stdio child via `--mcp-config`; tool calls land here
+//! and are translated to `AgentRequest::Send`/`Recv` against hyperhive's
+//! own per-agent unix socket at `/run/hive/mcp.sock`.
+//!
+//! Two protocols, two surfaces:
+//! - **hyperhive socket** at `/run/hive/mcp.sock` — JSON-line, our
+//!   broker-routed Send/Recv. Unaffected by this module.
+//! - **MCP stdio** owned by this module — what claude actually speaks.
+//!
+//! The agent surface today is intentionally tiny (send/recv); the manager
+//! surface (Phase 8 follow-up) will add `request_spawn`, `request_kill`,
+//! `request_apply_commit`.
+
+use std::path::PathBuf;
+
+use anyhow::Result;
+use rmcp::{
+    ServerHandler, ServiceExt,
+    handler::server::wrapper::Parameters,
+    schemars, tool, tool_handler, tool_router,
+    transport::stdio,
+};
+
+use crate::client;
+
+#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
+pub struct SendArgs {
+    /// Logical agent name to deliver the message to (e.g. `"manager"`,
+    /// `"alice"`, or the literal `"operator"` for the dashboard's T4LK box).
+    pub to: String,
+    /// Message body. Plain text; the broker doesn't parse it.
+    pub body: String,
+}
+
+#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
+pub struct RecvArgs {}
+
+/// Per-agent tool surface. Holds the socket path so each tool call doesn't
+/// re-derive it; the socket itself is the per-container `/run/hive/mcp.sock`.
+#[derive(Debug, Clone)]
+pub struct AgentServer {
+    socket: PathBuf,
+}
+
+impl AgentServer {
+    #[must_use]
+    pub fn new(socket: PathBuf) -> Self {
+        Self { socket }
+    }
+}
+
+#[tool_router]
+impl AgentServer {
+    #[tool(
+        description = "Send a message to another hyperhive agent (or to the operator). \
+            Use this to talk to peers or to surface output for the human at the dashboard."
+    )]
+    async fn send(&self, Parameters(args): Parameters<SendArgs>) -> String {
+        let req = hive_sh4re::AgentRequest::Send {
+            to: args.to.clone(),
+            body: args.body,
+        };
+        match client::request::<_, hive_sh4re::AgentResponse>(&self.socket, &req).await {
+            Ok(hive_sh4re::AgentResponse::Ok) => format!("sent to {}", args.to),
+            Ok(hive_sh4re::AgentResponse::Err { message }) => format!("send failed: {message}"),
+            Ok(other) => format!("send unexpected response: {other:?}"),
+            Err(e) => format!("send transport error: {e:#}"),
+        }
+    }
+
+    #[tool(
+        description = "Pop one message from this agent's inbox. Returns the sender and body, \
+            or an empty marker if nothing is waiting."
+    )]
+    async fn recv(&self, Parameters(_): Parameters<RecvArgs>) -> String {
+        let req = hive_sh4re::AgentRequest::Recv;
+        match client::request::<_, hive_sh4re::AgentResponse>(&self.socket, &req).await {
+            Ok(hive_sh4re::AgentResponse::Message { from, body }) => {
+                format!("from: {from}\n\n{body}")
+            }
+            Ok(hive_sh4re::AgentResponse::Empty) => "(empty)".into(),
+            Ok(hive_sh4re::AgentResponse::Err { message }) => format!("recv failed: {message}"),
+            Ok(other) => format!("recv unexpected response: {other:?}"),
+            Err(e) => format!("recv transport error: {e:#}"),
+        }
+    }
+}
+
+#[tool_handler(
+    instructions = "You are a hyperhive agent. Use `send` to talk to peers (by their logical \
+        name) or to the operator (recipient `operator`). Use `recv` to drain your inbox one \
+        message at a time."
+)]
+impl ServerHandler for AgentServer {}
+
+/// Run the MCP server over stdio. Returns when the client disconnects.
+pub async fn serve_stdio(socket: PathBuf) -> Result<()> {
+    let server = AgentServer::new(socket);
+    let service = server.serve(stdio()).await?;
+    service.waiting().await?;
+    Ok(())
+}