diff --git a/.claude/hooks/session-start.sh b/.claude/hooks/session-start.sh
new file mode 100755
index 0000000..fa797ef
--- /dev/null
+++ b/.claude/hooks/session-start.sh
@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+# Make sure rtk is on PATH, so the PreToolUse hook in .claude/settings.json has
+# something to call. Without this the sandbox starts every session with an empty
+# container and the rewrite hook quietly no-ops.
+#
+# Deliberately never fails: a missing rtk costs tokens, not correctness, and a
+# session that refuses to start because a compression tool did not download
+# would be a much worse trade.
+
+set -uo pipefail
+
+RTK_VERSION="v0.45.0"
+INSTALLER="https://raw.githubusercontent.com/rtk-ai/rtk/refs/heads/master/install.sh"
+
+export PATH="$HOME/.local/bin:$PATH"
+
+if command -v rtk >/dev/null 2>&1; then
+  exit 0
+fi
+
+# Only install unattended in the ephemeral web sandbox. On a personal machine,
+# say what to run instead — dropping a binary into someone's ~/.local/bin
+# without asking is not ours to do.
+if [ "${CLAUDE_CODE_REMOTE:-}" != "true" ]; then
+  echo "rtk is not installed, so bash output will not be compressed."
+  echo "To install it: curl -fsSL $INSTALLER | sh"
+  exit 0
+fi
+
+# The version has to be pinned. The installer's default is to look up the latest
+# tag through api.github.com, which the sandbox proxy answers with a 403 for
+# every repository except this one, so the lookup fails and takes the install
+# with it. Bump this by hand.
+if ! curl -fsSL "$INSTALLER" 2>/dev/null | RTK_VERSION="$RTK_VERSION" sh >/dev/null 2>&1; then
+  echo "rtk $RTK_VERSION did not install; continuing without output compression."
+  exit 0
+fi
+
+echo "rtk $(rtk --version 2>/dev/null | awk '{print $2}') ready; bash output is compressed."
diff --git a/.claude/settings.json b/.claude/settings.json
new file mode 100644
index 0000000..afcdbb8
--- /dev/null
+++ b/.claude/settings.json
@@ -0,0 +1,25 @@
+{
+  "hooks": {
+    "SessionStart": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "$CLAUDE_PROJECT_DIR/.claude/hooks/session-start.sh"
+          }
+        ]
+      }
+    ],
+    "PreToolUse": [
+      {
+        "matcher": "Bash",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "command -v rtk >/dev/null 2>&1 && exec rtk hook claude || exit 0"
+          }
+        ]
+      }
+    ]
+  }
+}
diff --git a/.rtk/filters.toml b/.rtk/filters.toml
new file mode 100644
index 0000000..d9bd43f
--- /dev/null
+++ b/.rtk/filters.toml
@@ -0,0 +1,13 @@
+# Project-local RTK filters — commit this file with your repo.
+# Filters here override user-global and built-in filters.
+# Docs: https://github.com/rtk-ai/rtk#custom-filters
+schema_version = 1
+
+# Example: suppress build noise from a custom tool
+# [filters.my-tool]
+# description = "Compact my-tool output"
+# match_command = "^my-tool\\s+build"
+# strip_ansi = true
+# strip_lines_matching = ["^\\s*$", "^Downloading", "^Installing"]
+# max_lines = 30
+# on_empty = "my-tool: ok"
diff --git a/CLAUDE.md b/CLAUDE.md
index 98dcdf1..858e8b5 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -67,3 +67,48 @@ The suppression is a property of the sandbox's credential, so it cannot be
 fixed from inside a session. Giving the environment a personal access token to
 push with would make pushes and PRs behave normally for everyone. Until then,
 the dispatch step above is the workaround.
+
+## Bash output is filtered before it reaches the model
+
+`.claude/settings.json` registers a `PreToolUse` hook on `Bash` that rewrites
+each command through [rtk](https://github.com/rtk-ai/rtk): `git status` runs as
+`rtk git status`, and rtk compresses the output. Write commands normally — the
+rewrite is transparent and costs nothing to invoke.
+
+Measured on this repo rather than quoted from rtk's README:
+
+| Command | Raw | Filtered | Saved |
+| --- | --- | --- | --- |
+| `git diff HEAD~3` | 521 KB | 28 KB | 95% |
+| `grep -rn "fun " app/src/main` | 117 KB | 19 KB | 84% |
+| `find . -name "*.kt"` | 7.7 KB | 1.7 KB | 79% |
+| `git log -20` | 20 KB | 5.3 KB | 74% |
+| `git diff --stat` | 4.0 KB | 4.0 KB | 1% |
+| `ls` of a single package | 50 B | 62 B | −24% |
+
+The saving is all in the large outputs, which is the point — a full diff of a
+few commits is otherwise most of a context window. Already-compact output grows
+slightly, because rtk adds a header; at those sizes it does not matter. `rtk
+gain` reports what the current session has actually saved.
+
+Two limits are worth knowing. The `Read`, `Grep` and `Glob` tools are not
+`Bash`, so they never reach the hook and are unaffected; a deliberate `rg` or
+`find` in a shell *is* filtered. And filtering never truncates a file: `cat`
+becomes `rtk read`, which was checked byte-for-byte against this repo's longest
+Kotlin source (`GameSetupScreen.kt`, 946 lines) and came back identical. Commit
+messages survive the rewrite intact, quotes and colons included. To bypass
+filtering for one command, run `rtk proxy <cmd>`.
+
+## rtk is reinstalled at the start of every session
+
+The container starts empty, so `.claude/hooks/session-start.sh` installs rtk
+before the session does anything. It pins `RTK_VERSION`, because the installer
+otherwise asks `api.github.com` for the latest tag and the proxy answers 403 for
+every repository except this one — the lookup fails and takes the install with
+it. Bump that variable by hand.
+
+The hook is written not to matter when it fails. Outside the sandbox it installs
+nothing and just prints the command to run, since dropping a binary into
+someone's `~/.local/bin` uninvited is not its business; if the download fails it
+says so and exits clean. With rtk absent the rewrite hook no-ops, and the only
+consequence is verbose output.
diff --git a/gradle.properties b/gradle.properties
index b8b27b0..cf29b77 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -16,10 +16,10 @@ android.nonTransitiveRClass=true
 # <series>.<run number>, a production tag is v<series>.<n> and a dev tag adds
 # -dev. It lives here rather than in the build file because the workflows have
 # to name the tag as well, and they read it straight out of this file — three
-# copies of "1.1" would be three chances for a release to be tagged one thing
+# copies of "1.2" would be three chances for a release to be tagged one thing
 # and built as another.
 #
 # Only the series is set by hand. The number after it is the CI run number, so
 # it keeps climbing on its own and an APK's versionCode never goes backwards
 # when this changes.
-plgVersionSeries=1.1
+plgVersionSeries=1.2