diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 35e377c..ec2f268 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,19 +1,49 @@
 name: CI
 
+# Pushes only build on `main'.  Work on a branch is covered by its pull
+# request, so without this bound every branch push would build twice.
 on:
   push:
     branches: [main]
+    paths-ignore:
+      - '**.md'
+      - LICENSE
   pull_request:
+    paths-ignore:
+      - '**.md'
+      - LICENSE
+
+# One live run per branch or pull request.  Pushing again supersedes the
+# run still going for the same ref, so a burst of commits costs one build
+# rather than one per commit.  Runs on `main' are left to finish: they are
+# the record that a released commit was green, and cancelling one would
+# leave a gap no later run fills.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
+# The job only reads the checkout.  Nothing here writes to the repository,
+# comments, or publishes, so the token gets no other scope.
+permissions:
+  contents: read
 
 jobs:
   test:
     runs-on: ubuntu-latest
+    # The suite runs in well under a second; the rest is provisioning
+    # Emacs.  This is a stop for a hang, not a target to tune against.
+    timeout-minutes: 10
     strategy:
       matrix:
-        emacs-version: [30.1]
+        # `Package-Requires' names 30.1 as the floor.  Kept to one version
+        # on purpose: each entry added here is another full build per push.
+        emacs-version: ['30.1']
     steps:
-      - uses: actions/checkout@v4
-      - uses: purcell/setup-emacs@master
+      # Both actions are pinned to a release rather than a branch: `master'
+      # moves under us, and an action that changes without a version bump
+      # turns a green build into an unreproducible one.
+      - uses: actions/checkout@v7
+      - uses: purcell/setup-emacs@v8.0
         with:
           version: ${{ matrix.emacs-version }}
       - name: Byte compile
diff --git a/README.md b/README.md
index 36ed919..c16df7f 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,19 @@
 # agent-shell-side
 
-Ask a quick question without derailing the conversation you are in.
+[![CI](https://github.com/liaowang11/agent-shell-side/actions/workflows/ci.yml/badge.svg)](https://github.com/liaowang11/agent-shell-side/actions/workflows/ci.yml)
+[![License: GPL v3](https://img.shields.io/badge/license-GPL--3.0--or--later-blue.svg)](LICENSE)
+
+Ask a quick side question in Emacs without derailing the AI coding session you
+are in.
+
+> [!WARNING]
+> **Experimental, and under active development.** Command names, options, and
+> the boundary instruction text can change without a deprecation period, and
+> this package is not on MELPA. Pin a commit if you depend on it. The live
+> probes have been run against one adapter only; see
+> [What has been tested live](#what-has-been-tested-live) for exactly what is
+> and is not proven, and [DESIGN.md](DESIGN.md) for what is deliberately
+> unbuilt.
 
 `M-x agent-shell-side` forks the current [agent-shell](https://github.com/xenodium/agent-shell)
 session into a second shell whose inherited history is demoted to reference
@@ -8,7 +21,11 @@ material. The agent can still read everything that came before, so the question
 needs no re-explaining, but it is told not to continue the parent's task, not to
 touch sub-agents, and not to change anything unless this conversation asks.
 
-Modelled on the `/side` command in OpenAI's Codex TUI.
+Modelled on the `/side` command in OpenAI's Codex TUI. It answers the same need
+as Claude Code's `/btw`, by a different mechanism: a real forked session that
+keeps its tools, rather than a single tool-less turn. Works with any coding
+agent that speaks the [Agent Client Protocol](https://agentclientprotocol.com)
+and advertises `session/fork`, such as claude-agent-acp.
 
 ## Install
 
diff --git a/agent-shell-side.el b/agent-shell-side.el
index 8583c41..e2146a5 100644
--- a/agent-shell-side.el
+++ b/agent-shell-side.el
@@ -13,6 +13,9 @@
 
 ;; Ask a quick question without derailing the conversation you are in.
 ;;
+;; Experimental, and under active development.  Command names, options, and
+;; the boundary instruction text can change without a deprecation period.
+;;
 ;; `agent-shell-side' forks the current session into a second shell whose
 ;; inherited history is demoted to reference material.  The agent can still
 ;; read everything that came before, so the question needs no re-explaining,