diff --git a/.github/workflows/python-package.yml b/.github/workflows/python-package.yml
index 9b4e9623..a124df9f 100644
--- a/.github/workflows/python-package.yml
+++ b/.github/workflows/python-package.yml
@@ -68,7 +68,7 @@ jobs:
 
       - run: |
           mk python-release owner=vkottler \
-                            repo=runtimepy version=3.11.3
+                            repo=runtimepy version=3.12.0
         if: |
           matrix.python-version == '3.11'
           && matrix.system == 'ubuntu-latest'
diff --git a/README.md b/README.md
index 3003803a..03bd6952 100644
--- a/README.md
+++ b/README.md
@@ -2,11 +2,11 @@
     =====================================
     generator=datazen
     version=3.1.4
-    hash=9985f72e34bdca8221f1d8d33ff6531a
+    hash=48f32e0cb1550ad416362e58fb185182
     =====================================
 -->
 
-# runtimepy ([3.11.3](https://pypi.org/project/runtimepy/))
+# runtimepy ([3.12.0](https://pypi.org/project/runtimepy/))
 
 [![python](https://img.shields.io/pypi/pyversions/runtimepy.svg)](https://pypi.org/project/runtimepy/)
 ![Build Status](https://github.com/vkottler/runtimepy/workflows/Python%20Package/badge.svg)
diff --git a/local/variables/package.yaml b/local/variables/package.yaml
index 2e15ffef..aefdecaa 100644
--- a/local/variables/package.yaml
+++ b/local/variables/package.yaml
@@ -1,5 +1,5 @@
 ---
 major: 3
-minor: 11
-patch: 3
+minor: 12
+patch: 0
 entry: runtimepy
diff --git a/pyproject.toml b/pyproject.toml
index ee63cdf8..bac5b877 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta:__legacy__"
 
 [project]
 name = "runtimepy"
-version = "3.11.3"
+version = "3.12.0"
 description = "A framework for implementing Python services."
 readme = "README.md"
 requires-python = ">=3.11"
diff --git a/runtimepy/__init__.py b/runtimepy/__init__.py
index e5975392..37eaef76 100644
--- a/runtimepy/__init__.py
+++ b/runtimepy/__init__.py
@@ -1,7 +1,7 @@
 # =====================================
 # generator=datazen
 # version=3.1.4
-# hash=4c241d22cd21592b757b41cc596fa46b
+# hash=4978a703b8ecd45735226f67d3cd0bf1
 # =====================================
 
 """
@@ -10,7 +10,7 @@
 
 DESCRIPTION = "A framework for implementing Python services."
 PKG_NAME = "runtimepy"
-VERSION = "3.11.3"
+VERSION = "3.12.0"
 
 # runtimepy-specific content.
 METRICS_NAME = "metrics"
diff --git a/runtimepy/channel/environment/command/processor.py b/runtimepy/channel/environment/command/processor.py
index f575d56e..06a2b0f2 100644
--- a/runtimepy/channel/environment/command/processor.py
+++ b/runtimepy/channel/environment/command/processor.py
@@ -37,7 +37,7 @@ def __init__(
         self.hooks: list[CommandHook] = []
 
         self.parser_data: dict[str, Any] = {}
-        self.parser = CommandParser()
+        self.parser = CommandParser(prog="")
         self.parser.data = self.parser_data
 
         self.parser.initialize()
diff --git a/runtimepy/data/css/bootstrap_extra.css b/runtimepy/data/css/bootstrap_extra.css
index 4938a18c..fb12fac6 100644
--- a/runtimepy/data/css/bootstrap_extra.css
+++ b/runtimepy/data/css/bootstrap_extra.css
@@ -52,3 +52,7 @@
 .collapse:not(.show) {
     display: none !important;
 }
+
+select.form-select {
+  width: min-content;
+}
diff --git a/runtimepy/data/js/classes/TabInterface.js b/runtimepy/data/js/classes/TabInterface.js
index fec99139..4deb3ca3 100644
--- a/runtimepy/data/js/classes/TabInterface.js
+++ b/runtimepy/data/js/classes/TabInterface.js
@@ -7,6 +7,9 @@ class TabInterface {
     this.name = name;
     this.worker = new WorkerInterface(this.name, _worker);
 
+    /* Send an initialization message. */
+    this.worker.send({kind : "init"});
+
     /* Relevant elements. */
     this.container = document.getElementById("runtimepy-" + this.name);
     this.logs = this.query("#" + this.name + "-logs");
@@ -25,22 +28,60 @@ class TabInterface {
         shown_tab = this.name;
       }
       this.worker.send({kind : msg});
-
-      /* Could remove this. */
-      this.log(msg);
     } ];
 
-    /* Plot related. */
+    this.initPlot();
+    this.initCommand();
+    this.initControls();
+    this.initButton();
+  }
+
+  initCommand() {
+    let command = this.query("#" + this.name + "-command")
+    if (command) {
+      command.onkeypress = (event) => {
+        if (event.key == "Enter") {
+          let cmd = event.target.value.trim();
+
+          if (cmd == "cls" || cmd == "clear") {
+            this.clearLog();
+          } else {
+            this.command(cmd);
+          }
+
+          event.target.value = "";
+        }
+      };
+    }
+  }
+
+  command(data) { this.worker.send({kind : "command", value : data}); }
+
+  initControls() {
+    /* Initialize enumeration command drop downs. */
+    for (let enums of this.queryAll("select")) {
+      enums.onchange =
+          (() => { this.command(`set ${enums.id} ${enums.value}`); })
+              .bind(this);
+    }
+
+    /* Initialize toggle buttons. */
+    for (let toggle of this.queryAll("td>button")) {
+      toggle.onclick =
+          (() => { this.command(`toggle ${toggle.id}`); }).bind(this);
+    }
+  }
+
+  initPlot() {
     let plot = this.query("#" + this.name + "-plot");
     if (plot) {
       this.plot = new Plot(plot, this.worker);
       this.show_state_handlers.push(this.plot.handle_shown.bind(this.plot));
     }
-
-    this.initButton();
   }
 
   query(data) { return this.container.querySelector(data); }
+  queryAll(data) { return this.container.querySelectorAll(data); }
 
   initButton() {
     let button = document.getElementById("runtimepy-" + this.name + "-tab");
@@ -52,12 +93,13 @@ class TabInterface {
   }
 
   log(message) {
-    console.log(`(${this.name}) ` + message);
     if (this.logs) {
       this.logs.value += message + "\n";
     }
   }
 
+  clearLog() { this.logs.value = ""; }
+
   show_state_handler(is_shown) {
     for (const handler of this.show_state_handlers) {
       handler(is_shown);
@@ -69,6 +111,10 @@ class TabInterface {
   hidden_handler() { this.show_state_handler(false); }
 
   onmessage(data) {
+    if ("log_message" in data) {
+      this.log(data["log_message"]);
+    }
+
     for (const handler of this.message_handlers) {
       handler(data);
     }
diff --git a/runtimepy/net/server/app/bootstrap/elements.py b/runtimepy/net/server/app/bootstrap/elements.py
index 45a07d7c..ad1ab6a3 100644
--- a/runtimepy/net/server/app/bootstrap/elements.py
+++ b/runtimepy/net/server/app/bootstrap/elements.py
@@ -67,7 +67,7 @@ def collapse_button(
     return collapse
 
 
-def toggle_button(parent: Element) -> Element:
+def toggle_button(parent: Element, **kwargs) -> Element:
     """Add a boolean-toggle button."""
 
     return div(
@@ -77,6 +77,7 @@ def toggle_button(parent: Element) -> Element:
         parent=parent,
         title="toggle value",
         class_str="btn " + BOOTSTRAP_BUTTON,
+        **kwargs,
     )
 
 
@@ -85,6 +86,7 @@ def input_box(
     label: str = "filter",
     pattern: str = ".*",
     description: str = None,
+    **kwargs,
 ) -> None:
     """Create command input box."""
 
@@ -103,5 +105,6 @@ def input_box(
         parent=container,
         name=label,
         title=label + " input",
+        **kwargs,
     )
     box.add_class("form-control", "rounded-0", TEXT)
diff --git a/runtimepy/net/server/app/env/__init__.py b/runtimepy/net/server/app/env/__init__.py
index a5983035..eecf2403 100644
--- a/runtimepy/net/server/app/env/__init__.py
+++ b/runtimepy/net/server/app/env/__init__.py
@@ -21,9 +21,6 @@ def channel_environments(app: AppInfo, tabs: TabbedContent) -> None:
     # Tab name filter.
     input_box(tabs.tabs, label="tab", description="Tab name filter.")
 
-    # Sound tab.
-    SoundTab("sound", app, tabs, source="sound", icon="boombox").entry()
-
     # Connection tabs.
     for name, conn in app.connections.items():
         ChannelEnvironmentTab(
@@ -36,6 +33,9 @@ def channel_environments(app: AppInfo, tabs: TabbedContent) -> None:
             name, task.command, app, tabs, icon="arrow-repeat"
         ).entry()
 
+    # Sound tab.
+    SoundTab("sound", app, tabs, source="sound", icon="boombox").entry()
+
     dummy_tabs(3, app, tabs)
 
     # Toggle channel-table button.
diff --git a/runtimepy/net/server/app/env/tab/__init__.py b/runtimepy/net/server/app/env/tab/__init__.py
new file mode 100644
index 00000000..4e58ea17
--- /dev/null
+++ b/runtimepy/net/server/app/env/tab/__init__.py
@@ -0,0 +1,25 @@
+"""
+A module implementing a channel-environment tab HTML interface.
+"""
+
+# internal
+from runtimepy.net.server.app.env.tab.html import ChannelEnvironmentTabHtml
+from runtimepy.net.server.app.env.tab.message import (
+    ChannelEnvironmentTabMessaging,
+)
+
+
+class ChannelEnvironmentTab(
+    ChannelEnvironmentTabMessaging, ChannelEnvironmentTabHtml
+):
+    """A class aggregating all channel-environment tab interfaces."""
+
+    all_tabs: dict[str, "ChannelEnvironmentTab"] = {}
+
+    def init(self) -> None:
+        """Initialize this instance."""
+
+        super().init()
+
+        # Update global mapping.
+        type(self).all_tabs[self.name] = self
diff --git a/runtimepy/net/server/app/env/tab/base.py b/runtimepy/net/server/app/env/tab/base.py
new file mode 100644
index 00000000..656e61c9
--- /dev/null
+++ b/runtimepy/net/server/app/env/tab/base.py
@@ -0,0 +1,28 @@
+"""
+A module implementing a channel-environment tab HTML interface.
+"""
+
+# internal
+from runtimepy.channel.environment.command.processor import (
+    ChannelCommandProcessor,
+)
+from runtimepy.net.arbiter.info import AppInfo
+from runtimepy.net.server.app.bootstrap.tabs import TabbedContent
+from runtimepy.net.server.app.tab import Tab
+
+
+class ChannelEnvironmentTabBase(Tab):
+    """A channel-environment tab interface."""
+
+    def __init__(
+        self,
+        name: str,
+        command: ChannelCommandProcessor,
+        app: AppInfo,
+        tabs: TabbedContent,
+        icon: str = "alarm",
+    ) -> None:
+        """Initialize this instance."""
+
+        self.command = command
+        super().__init__(name, app, tabs, source="env", icon=icon)
diff --git a/runtimepy/net/server/app/env/tab.py b/runtimepy/net/server/app/env/tab/html.py
similarity index 65%
rename from runtimepy/net/server/app/env/tab.py
rename to runtimepy/net/server/app/env/tab/html.py
index 33a0cf5f..aae83f87 100644
--- a/runtimepy/net/server/app/env/tab.py
+++ b/runtimepy/net/server/app/env/tab/html.py
@@ -3,18 +3,14 @@
 """
 
 # built-in
-from typing import Optional
+from typing import Optional, cast
 
 # third-party
 from svgen.element import Element
 
 # internal
 from runtimepy.channel import AnyChannel
-from runtimepy.channel.environment.command.processor import (
-    ChannelCommandProcessor,
-)
 from runtimepy.enum import RuntimeEnum
-from runtimepy.net.arbiter.info import AppInfo
 from runtimepy.net.server.app.bootstrap.elements import (
     TEXT,
     flex,
@@ -22,54 +18,19 @@
     set_tooltip,
     toggle_button,
 )
-from runtimepy.net.server.app.bootstrap.tabs import TabbedContent
 from runtimepy.net.server.app.elements import div
+from runtimepy.net.server.app.env.tab.base import ChannelEnvironmentTabBase
+from runtimepy.net.server.app.env.widgets import (
+    channel_table_header,
+    enum_dropdown,
+    plot_checkbox,
+)
 from runtimepy.net.server.app.placeholder import under_construction
-from runtimepy.net.server.app.tab import Tab
-
-
-def plot_checkbox(parent: Element, name: str) -> None:
-    """Add a checkbox for individual channel plot status."""
-
-    container = div(tag="td", parent=parent)
-
-    set_tooltip(
-        div(
-            tag="input",
-            type="checkbox",
-            value="",
-            id=f"plot-{name}",
-            allow_no_end_tag=True,
-            parent=container,
-            class_str="form-check-input",
-        ),
-        f"Enable plotting channel '{name}'.",
-    )
-
 
-def enum_dropdown(parent: Element, enum: Optional[RuntimeEnum]) -> None:
-    """Implement a drop down for enumeration options."""
 
-    del enum
-    div(parent=parent, text="TODO")
-
-
-class ChannelEnvironmentTab(Tab):
+class ChannelEnvironmentTabHtml(ChannelEnvironmentTabBase):
     """A channel-environment tab interface."""
 
-    def __init__(
-        self,
-        name: str,
-        command: ChannelCommandProcessor,
-        app: AppInfo,
-        tabs: TabbedContent,
-        icon: str = "alarm",
-    ) -> None:
-        """Initialize this instance."""
-
-        self.command = command
-        super().__init__(name, app, tabs, source="env", icon=icon)
-
     def add_channel(
         self,
         parent: Element,
@@ -91,19 +52,19 @@ def add_channel(
             kind_str = enum_name
 
         # Add boolean/bit toggle button.
-        control = div(tag="td", parent=parent)
+        control = div(tag="td", parent=parent, class_str="text-center")
 
         chan_type = div(tag="td", text=kind_str, parent=parent)
         if enum:
             chan_type.add_class("fw-bold")
 
             if chan.commandable and not chan.type.is_boolean:
-                enum_dropdown(control, enum)
+                enum_dropdown(control, name, enum, cast(int, chan.raw.value))
 
         if chan.type.is_boolean:
             chan_type.add_class("text-primary-emphasis")
             if chan.commandable:
-                toggle_button(control)["title"] = f"Toggle '{name}'."
+                toggle_button(control, id=name)["title"] = f"Toggle '{name}'."
 
         elif chan.type.is_float:
             chan_type.add_class("text-secondary-emphasis")
@@ -131,7 +92,7 @@ def add_field(self, parent: Element, name: str) -> None:
         if field.is_enum:
             enum = env.enums[field.enum]
 
-        control = div(tag="td", parent=parent)
+        control = div(tag="td", parent=parent, class_str="text-center")
 
         # Add boolean/bit toggle button.
         is_bit = field.width == 1
@@ -145,9 +106,9 @@ def add_field(self, parent: Element, name: str) -> None:
         if field.commandable:
             name_elem.add_class("text-success")
             if is_bit:
-                toggle_button(control)
+                toggle_button(control, id=name)
             elif enum:
-                enum_dropdown(control, enum)
+                enum_dropdown(control, name, enum, field())
 
         div(tag="td", text=str(env.value(name)), parent=parent)
 
@@ -161,34 +122,7 @@ def channel_table(self, parent: Element) -> None:
         body = div(tag="tbody", parent=table)
 
         # Add header.
-        header_row = div(tag="tr", parent=header)
-        for heading, desc in [
-            ("plot", "Toggle plotting for channels."),
-            ("ctl", "Type-specific channel controls."),
-            ("type", "Channel types."),
-            ("name", "Channel names."),
-            ("value", "Channel values."),
-        ]:
-            set_tooltip(
-                div(
-                    tag="th",
-                    scope="col",
-                    parent=header_row,
-                    text=heading,
-                    class_str="text-secondary",
-                ),
-                desc,
-                placement="bottom",
-            )
-
-        # Add some controls.
-        ctl_row = div(tag="tr", parent=header)
-        for _ in range(3):
-            div(tag="th", parent=ctl_row)
-        input_box(
-            div(tag="th", parent=ctl_row), description="Channel name filter."
-        )
-        div(tag="th", parent=ctl_row)
+        channel_table_header(header)
 
         env = self.command.env
 
@@ -210,6 +144,10 @@ def channel_table(self, parent: Element) -> None:
             else:
                 self.add_field(row, name)
 
+    def get_id(self, data: str) -> str:
+        """Get an HTML id for an element."""
+        return f"{self.name}-{data}"
+
     def compose(self, parent: Element) -> None:
         """Compose the tab's HTML elements."""
 
@@ -231,6 +169,7 @@ def compose(self, parent: Element) -> None:
             label="command",
             pattern="help",
             description="Send a string command via this environment.",
+            id=self.get_id("command"),
         )
 
         # Text area.
@@ -238,7 +177,7 @@ def compose(self, parent: Element) -> None:
             tag="textarea",
             parent=div(parent=vert_container, class_str="form-floating"),
             class_str=f"form-control rounded-0 {TEXT}",
-            id=f"{self.name}-logs",
+            id=self.get_id("logs"),
             title=f"Text logs for {self.name}.",
         )
         logs.booleans.add("readonly")
@@ -252,7 +191,7 @@ def compose(self, parent: Element) -> None:
         # Plot.
         div(
             tag="canvas",
-            id=f"{self.name}-plot",
+            id=self.get_id("plot"),
             parent=div(parent=container, class_str="w-100 h-100"),
             class_str="w-100 h-100",
         )
diff --git a/runtimepy/net/server/app/env/tab/logger.py b/runtimepy/net/server/app/env/tab/logger.py
new file mode 100644
index 00000000..bac77adc
--- /dev/null
+++ b/runtimepy/net/server/app/env/tab/logger.py
@@ -0,0 +1,34 @@
+"""
+A module implementing a simple logger interface for tabs.
+"""
+
+# built-in
+import logging
+from typing import Callable
+
+# third-party
+from vcorelib.logging import DEFAULT_TIME_FORMAT
+
+# internal
+from runtimepy.net.stream.json.types import JsonMessage
+
+TabMessageSender = Callable[[JsonMessage], None]
+
+
+class TabLogger(logging.Handler):
+    """An interface facilitating sending log messages to browser tabs."""
+
+    send: TabMessageSender
+
+    def emit(self, record):
+        """Send the log message."""
+        self.send({"log_message": self.format(record)})
+
+    @staticmethod
+    def create(send: TabMessageSender) -> "TabLogger":
+        """Create a tab logger handler."""
+
+        handler = TabLogger()
+        handler.send = send
+        handler.setFormatter(logging.Formatter(DEFAULT_TIME_FORMAT))
+        return handler
diff --git a/runtimepy/net/server/app/env/tab/message.py b/runtimepy/net/server/app/env/tab/message.py
new file mode 100644
index 00000000..2482219b
--- /dev/null
+++ b/runtimepy/net/server/app/env/tab/message.py
@@ -0,0 +1,80 @@
+"""
+A module implementing a channel-environment tab message-handling interface.
+"""
+
+# built-in
+import logging
+from typing import Any
+
+# internal
+from runtimepy.net.server.app.env.tab.base import ChannelEnvironmentTabBase
+from runtimepy.net.server.app.env.tab.logger import TabLogger, TabMessageSender
+from runtimepy.net.stream.json.types import JsonMessage
+
+
+class ChannelEnvironmentTabMessaging(ChannelEnvironmentTabBase):
+    """A channel-environment tab interface."""
+
+    shown: bool
+
+    def init(self) -> None:
+        """Initialize this instance."""
+
+        super().init()
+        self.shown = False
+
+    def handle_shown_state(self, shown: bool, outbox: JsonMessage) -> None:
+        """Handle 'shown' state changing."""
+
+        self.shown = shown
+
+        outbox["handle_shown_state"] = shown
+
+    def handle_init(self, outbox: JsonMessage, send: TabMessageSender) -> None:
+        """Handle tab initialization."""
+
+        del outbox
+
+        logger: logging.Logger = self.command.logger  # type: ignore
+
+        # Add a log handler.
+        logger.addHandler(TabLogger.create(send))
+
+        logger.info("Tab initialized.")
+
+    async def handle_message(
+        self, data: dict[str, Any], send: TabMessageSender
+    ) -> JsonMessage:
+        """Handle a message from a tab."""
+
+        kind: str = data["kind"]
+        response: JsonMessage = {}
+
+        # Respond to initialization.
+        if kind == "init":
+            self.handle_init(response, send)
+
+        # Handle command-line commands.
+        elif kind == "command":
+            cmd = self.command
+            result = cmd.command(data["value"])
+
+            cmd.logger.log(
+                logging.INFO if result else logging.ERROR,
+                "%s: %s",
+                data["value"],
+                result,
+            )
+
+        # Handle tab-event messages.
+        elif kind.startswith("tab"):
+            if "shown" in kind:
+                self.handle_shown_state(True, response)
+            elif "hidden" in kind:
+                self.handle_shown_state(False, response)
+
+        # Log when messages aren't handled.
+        else:
+            self.command.logger.warning("Message not handled: '%s'.", data)
+
+        return response
diff --git a/runtimepy/net/server/app/env/widgets.py b/runtimepy/net/server/app/env/widgets.py
new file mode 100644
index 00000000..45fd8996
--- /dev/null
+++ b/runtimepy/net/server/app/env/widgets.py
@@ -0,0 +1,90 @@
+"""
+Channel-environment tab widget interfaces.
+"""
+
+# built-in
+from typing import cast
+
+# third-party
+from svgen.element import Element
+
+# internal
+from runtimepy.enum import RuntimeEnum
+from runtimepy.net.server.app.bootstrap.elements import input_box, set_tooltip
+from runtimepy.net.server.app.elements import div
+
+
+def plot_checkbox(parent: Element, name: str) -> None:
+    """Add a checkbox for individual channel plot status."""
+
+    container = div(tag="td", parent=parent)
+
+    set_tooltip(
+        div(
+            tag="input",
+            type="checkbox",
+            value="",
+            id=f"plot-{name}",
+            allow_no_end_tag=True,
+            parent=container,
+            class_str="form-check-input",
+        ),
+        f"Enable plotting channel '{name}'.",
+    )
+
+
+def enum_dropdown(
+    parent: Element, name: str, enum: RuntimeEnum, current: int | bool
+) -> None:
+    """Implement a drop down for enumeration options."""
+
+    title = f"Enumeration selection for '{name}'."
+    select = div(
+        tag="select",
+        parent=parent,
+        class_str="form-select",
+        title=title,
+        id=name,
+    )
+    select["aria-label"] = title
+
+    for key, val in cast(dict[str, dict[str, int | bool]], enum.asdict())[
+        "items"
+    ].items():
+        opt = div(tag="option", value=key, text=key, parent=select)
+        if current == val:
+            opt.booleans.add("selected")
+
+
+def channel_table_header(parent: Element) -> None:
+    """Add header row to channel table.."""
+
+    # Add header.
+    header_row = div(tag="tr", parent=parent)
+    for heading, desc in [
+        ("plot", "Toggle plotting for channels."),
+        ("ctl", "Type-specific channel controls."),
+        ("type", "Channel types."),
+        ("name", "Channel names."),
+        ("value", "Channel values."),
+    ]:
+        set_tooltip(
+            div(
+                tag="th",
+                scope="col",
+                parent=header_row,
+                text=heading,
+                class_str="text-secondary",
+            ),
+            desc,
+            placement="bottom",
+        )
+
+    # Add some controls.
+    ctl_row = div(tag="tr", parent=parent)
+    for _ in range(3):
+        div(tag="th", parent=ctl_row)
+    input_box(
+        div(tag="th", parent=ctl_row), description="Channel name filter."
+    )
+    div(tag="th", parent=ctl_row)
diff --git a/runtimepy/net/server/app/tab.py b/runtimepy/net/server/app/tab.py
index f5348eef..13a49e95 100644
--- a/runtimepy/net/server/app/tab.py
+++ b/runtimepy/net/server/app/tab.py
@@ -46,8 +46,13 @@ def __init__(
         button_str += self.name
         self.button.text = button_str
 
+        self.init()
+
         self.compose(self.content)
 
+    def init(self) -> None:
+        """Initialize this instance."""
+
     def compose(self, parent: Element) -> None:
         """Compose the tab's HTML elements."""
 
diff --git a/runtimepy/net/server/websocket/__init__.py b/runtimepy/net/server/websocket/__init__.py
index 1b6f6157..a35cb97c 100644
--- a/runtimepy/net/server/websocket/__init__.py
+++ b/runtimepy/net/server/websocket/__init__.py
@@ -4,6 +4,8 @@
 
 # internal
 from runtimepy.net.arbiter.tcp.json import WebsocketJsonMessageConnection
+from runtimepy.net.server.app.env.tab import ChannelEnvironmentTab
+from runtimepy.net.server.app.env.tab.message import TabMessageSender
 from runtimepy.net.stream.json.types import JsonMessage
 from runtimepy.net.websocket import WebsocketConnection
 
@@ -11,18 +13,40 @@
 class RuntimepyWebsocketConnection(WebsocketJsonMessageConnection):
     """A class implementing a package-specific WebSocket connection."""
 
+    send_interfaces: dict[str, TabMessageSender]
+
+    def tab_sender(self, name: str) -> TabMessageSender:
+        """Get a tab message-sending interface."""
+
+        if name not in self.send_interfaces:
+
+            def sender(data: JsonMessage) -> None:
+                """Tab-message sending interface."""
+                self.send_json({"ui": {name: data}})
+
+            self.send_interfaces[name] = sender
+
+        return self.send_interfaces[name]
+
     def _register_handlers(self) -> None:
         """Register connection-specific command handlers."""
 
         super()._register_handlers()
+        self.send_interfaces = {}
 
         async def ui_handler(outbox: JsonMessage, inbox: JsonMessage) -> None:
             """A simple loopback handler."""
 
-            self.logger.info("Got UI message: %s.", inbox)
-
-            # Connect tabs to tab messaging somehow.
-            outbox[inbox["name"]] = inbox["event"]
+            # Handle messages from tabs.
+            if "name" in inbox and "event" in inbox:
+                name = inbox["name"]
+                tab = ChannelEnvironmentTab.all_tabs.get(name)
+                if tab is not None:
+                    response = await tab.handle_message(
+                        inbox["event"], self.tab_sender(name)
+                    )
+                    if response:
+                        outbox[name] = response
 
         self.basic_handler("ui", ui_handler)
 
diff --git a/runtimepy/task/sample.py b/runtimepy/task/sample.py
index d2d3872f..095b73cd 100644
--- a/runtimepy/task/sample.py
+++ b/runtimepy/task/sample.py
@@ -82,6 +82,7 @@ async def init(self, app: AppInfo) -> None:
                         self.env.int_channel(
                             "really_really_long_enum",
                             enum="InsanelyLongEnumNameForTesting",
+                            commandable=True,
                         )
                         self.env.bool_channel("bool")
                         self.env.int_channel("int", commandable=True)