Build public release readiness foundation

2026-06-26 05:44:38 +08:00 · 2026-05-26 09:42:14 +08:00 · 2026-05-26 09:42:14 +08:00 · 33e2dc4f13
commit 33e2dc4f13
parent 94b602613f
40 changed files with 1570 additions and 140 deletions
--- a/.github/ISSUE_TEMPLATE/bug_report.yml
+++ b/.github/ISSUE_TEMPLATE/bug_report.yml
@ -0,0 +1,64 @@
 name: Bug Report
 description: Report a reproducible problem in TNT.
 labels: ["bug"]
 body:
  - type: markdown
    attributes:
      value: |
        For security vulnerabilities, do not open a public issue. See SECURITY.md.
  - type: input
    id: version
    attributes:
      label: Version
      description: Run `tnt --version`, or provide the commit hash.
      placeholder: "tnt 1.0.1"
    validations:
      required: true
  - type: dropdown
    id: install_method
    attributes:
      label: Installation Method
      options:
        - GitHub release binary
        - Source build
        - install.sh
        - Package manager draft
        - Other
    validations:
      required: true
  - type: input
    id: platform
    attributes:
      label: Platform
      placeholder: "Ubuntu 24.04 x86_64, Arch Linux, macOS 15 arm64"
    validations:
      required: true
  - type: textarea
    id: repro
    attributes:
      label: Reproduction Steps
      description: Keep this as small and concrete as possible.
      placeholder: |
        1. Start TNT with ...
        2. Connect with ...
        3. Run ...
    validations:
      required: true
  - type: textarea
    id: expected
    attributes:
      label: Expected Behavior
    validations:
      required: true
  - type: textarea
    id: actual
    attributes:
      label: Actual Behavior
    validations:
      required: true
  - type: textarea
    id: logs
    attributes:
      label: Relevant Logs
      description: Remove secrets, access tokens, and private hostnames.
      render: text
--- a/.github/ISSUE_TEMPLATE/config.yml
+++ b/.github/ISSUE_TEMPLATE/config.yml
@ -0,0 +1,5 @@
 blank_issues_enabled: true
 contact_links:
  - name: Security vulnerability
    url: https://github.com/m1ngsama/TNT/security
    about: Do not open public issues for vulnerabilities. See SECURITY.md for private reporting paths.
--- a/.github/ISSUE_TEMPLATE/feature_request.yml
+++ b/.github/ISSUE_TEMPLATE/feature_request.yml
@ -0,0 +1,37 @@
 name: Feature Request
 description: Suggest a focused improvement to TNT.
 labels: ["enhancement"]
 body:
  - type: textarea
    id: problem
    attributes:
      label: Problem
      description: What workflow or limitation should this improve?
    validations:
      required: true
  - type: textarea
    id: proposal
    attributes:
      label: Proposal
      description: Describe the smallest useful behavior change.
    validations:
      required: true
  - type: dropdown
    id: area
    attributes:
      label: Area
      options:
        - Interactive TUI
        - SSH exec / scripting
        - Packaging / release
        - Operations / systemd
        - Security
        - Documentation
        - Other
    validations:
      required: true
  - type: textarea
    id: alternatives
    attributes:
      label: Alternatives Considered
      description: Optional. Existing commands, scripts, or workflows you tried.
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@ -6,6 +6,9 @@ on:
  pull_request:
    branches: [ main ]
 permissions:
  contents: read
 jobs:
  build-and-test:
    runs-on: ${{ matrix.os }}
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@ -5,6 +5,9 @@ on:
    tags:
      - 'v*'
 permissions:
  contents: read
 jobs:
  build:
    name: Build ${{ matrix.target }}
@ -15,15 +18,19 @@ jobs:
          - os: ubuntu-24.04
            target: linux-amd64
            artifact: tnt-linux-amd64
            ctl_artifact: tntctl-linux-amd64
          - os: ubuntu-24.04-arm
            target: linux-arm64
            artifact: tnt-linux-arm64
            ctl_artifact: tntctl-linux-arm64
          - os: macos-15-intel
            target: darwin-amd64
            artifact: tnt-darwin-amd64
            ctl_artifact: tntctl-darwin-amd64
          - os: macos-15
            target: darwin-arm64
            artifact: tnt-darwin-arm64
            ctl_artifact: tntctl-darwin-arm64
    steps:
    - uses: actions/checkout@v4
@ -48,29 +55,38 @@ jobs:
    - name: Verify artifact architecture
      run: |
        file tnt
        file tntctl
        case "${{ matrix.target }}" in
          linux-amd64)
            file tnt | grep -E 'ELF 64-bit.*x86-64'
            file tntctl | grep -E 'ELF 64-bit.*x86-64'
            ;;
          linux-arm64)
            file tnt | grep -E 'ELF 64-bit.*(aarch64|ARM aarch64)'
            file tntctl | grep -E 'ELF 64-bit.*(aarch64|ARM aarch64)'
            ;;
          darwin-amd64)
            file tnt | grep -E 'Mach-O 64-bit.*x86_64'
            file tntctl | grep -E 'Mach-O 64-bit.*x86_64'
            ;;
          darwin-arm64)
            file tnt | grep -E 'Mach-O 64-bit.*arm64'
            file tntctl | grep -E 'Mach-O 64-bit.*arm64'
            ;;
        esac
    - name: Rename binary
-      run: mv tnt ${{ matrix.artifact }}
+      run: |
        mv tnt ${{ matrix.artifact }}
        mv tntctl ${{ matrix.ctl_artifact }}
    - name: Upload artifact
      uses: actions/upload-artifact@v4
      with:
        name: ${{ matrix.artifact }}
-        path: ${{ matrix.artifact }}
+        path: |
          ${{ matrix.artifact }}
          ${{ matrix.ctl_artifact }}
  release:
    needs: build
@ -90,7 +106,8 @@ jobs:
      run: |
        cd artifacts
        : > checksums.txt
-        for artifact in */tnt-*; do
+        for artifact in */tnt-* */tntctl-*; do
          [ -f "$artifact" ] || continue
          sha256sum "$artifact" | sed "s#  $artifact#  $(basename "$artifact")#" >> checksums.txt
        done
        cat checksums.txt
@ -100,6 +117,7 @@ jobs:
      with:
        files: |
          artifacts/*/tnt-*
          artifacts/*/tntctl-*
          artifacts/checksums.txt
        body: |
          ## Installation
@ -109,29 +127,41 @@ jobs:
          **Linux AMD64:**
          ```bash
          wget https://github.com/${{ github.repository }}/releases/download/${{ github.ref_name }}/tnt-linux-amd64
          wget https://github.com/${{ github.repository }}/releases/download/${{ github.ref_name }}/tntctl-linux-amd64
          chmod +x tnt-linux-amd64
          chmod +x tntctl-linux-amd64
          sudo mv tnt-linux-amd64 /usr/local/bin/tnt
          sudo mv tntctl-linux-amd64 /usr/local/bin/tntctl
          ```
          **Linux ARM64:**
          ```bash
          wget https://github.com/${{ github.repository }}/releases/download/${{ github.ref_name }}/tnt-linux-arm64
          wget https://github.com/${{ github.repository }}/releases/download/${{ github.ref_name }}/tntctl-linux-arm64
          chmod +x tnt-linux-arm64
          chmod +x tntctl-linux-arm64
          sudo mv tnt-linux-arm64 /usr/local/bin/tnt
          sudo mv tntctl-linux-arm64 /usr/local/bin/tntctl
          ```
          **macOS Intel:**
          ```bash
          wget https://github.com/${{ github.repository }}/releases/download/${{ github.ref_name }}/tnt-darwin-amd64
          wget https://github.com/${{ github.repository }}/releases/download/${{ github.ref_name }}/tntctl-darwin-amd64
          chmod +x tnt-darwin-amd64
          chmod +x tntctl-darwin-amd64
          sudo mv tnt-darwin-amd64 /usr/local/bin/tnt
          sudo mv tntctl-darwin-amd64 /usr/local/bin/tntctl
          ```
          **macOS Apple Silicon:**
          ```bash
          wget https://github.com/${{ github.repository }}/releases/download/${{ github.ref_name }}/tnt-darwin-arm64
          wget https://github.com/${{ github.repository }}/releases/download/${{ github.ref_name }}/tntctl-darwin-arm64
          chmod +x tnt-darwin-arm64
          chmod +x tntctl-darwin-arm64
          sudo mv tnt-darwin-arm64 /usr/local/bin/tnt
          sudo mv tntctl-darwin-arm64 /usr/local/bin/tntctl
          ```
          **Verify checksums:**
--- a/.gitignore
+++ b/.gitignore
@ -1,6 +1,7 @@
 *.o
 obj/
 tnt
 tntctl
 messages.log
 host_key
 host_key.pub
--- a/32
+++ b/32
@ -20,10 +20,13 @@ SRC_DIR = src
 INC_DIR = include
 OBJ_DIR = obj
-SOURCES = $(wildcard $(SRC_DIR)/*.c)
+SOURCES = $(filter-out $(SRC_DIR)/tntctl.c,$(wildcard $(SRC_DIR)/*.c))
 OBJECTS = $(SOURCES:$(SRC_DIR)/%.c=$(OBJ_DIR)/%.o)
-DEPS = $(OBJECTS:.o=.d)
+DEPS = $(OBJECTS:.o=.d) $(CTL_OBJECTS:.o=.d)
 TARGET = tnt
 CTL_TARGET = tntctl
 CTL_OBJECTS = $(OBJ_DIR)/tntctl.o
 TARGETS = $(TARGET) $(CTL_TARGET)
 PREFIX ?= /usr/local
 BINDIR ?= $(PREFIX)/bin
@ -33,12 +36,16 @@ CI_TEST_PORT ?= $(if $(PORT),$(PORT),2222)
 .PHONY: all clean install install-systemd uninstall uninstall-systemd debug release release-check release-check-strict asan valgrind check test test-advisory ci-test unit-test integration-test anonymous-access-test connection-limit-test security-test stress-test info
-all: $(TARGET)
+all: $(TARGETS)
 $(TARGET): $(OBJECTS)
 	$(CC) $(OBJECTS) -o $@ $(LDFLAGS)
 	@echo "Build complete: $(TARGET)"
 $(CTL_TARGET): $(CTL_OBJECTS)
 	$(CC) $(CTL_OBJECTS) -o $@
 	@echo "Build complete: $(CTL_TARGET)"
 $(OBJ_DIR)/%.o: $(SRC_DIR)/%.c | $(OBJ_DIR)
 	$(CC) $(CFLAGS) $(DEPFLAGS) $(INCLUDES) -c $< -o $@
@ -46,34 +53,40 @@ $(OBJ_DIR):
 	mkdir -p $(OBJ_DIR)
 clean:
-	rm -rf $(OBJ_DIR) $(TARGET)
+	rm -rf $(OBJ_DIR) $(TARGETS)
 	rm -f tests/*.log tests/host_key* tests/messages.log
 	@echo "Clean complete"
-install: $(TARGET)
+install: $(TARGETS)
 	install -d $(DESTDIR)$(BINDIR)
 	install -m 755 $(TARGET) $(DESTDIR)$(BINDIR)/
 	install -m 755 $(CTL_TARGET) $(DESTDIR)$(BINDIR)/
 	install -d $(DESTDIR)$(MANDIR)/man1
 	install -m 644 tnt.1 $(DESTDIR)$(MANDIR)/man1/
 	install -m 644 tntctl.1 $(DESTDIR)$(MANDIR)/man1/
 install-systemd:
 	install -d $(DESTDIR)$(SYSTEMD_UNIT_DIR)
-	install -m 644 tnt.service $(DESTDIR)$(SYSTEMD_UNIT_DIR)/
+	sed 's#^ExecStart=.*#ExecStart=$(BINDIR)/$(TARGET)#' tnt.service > "$(DESTDIR)$(SYSTEMD_UNIT_DIR)/tnt.service"
 	chmod 644 "$(DESTDIR)$(SYSTEMD_UNIT_DIR)/tnt.service"
 uninstall:
 	rm -f $(DESTDIR)$(BINDIR)/$(TARGET)
 	rm -f $(DESTDIR)$(BINDIR)/$(CTL_TARGET)
 	rm -f $(DESTDIR)$(MANDIR)/man1/tnt.1
 	rm -f $(DESTDIR)$(MANDIR)/man1/tntctl.1
 uninstall-systemd:
 	rm -f $(DESTDIR)$(SYSTEMD_UNIT_DIR)/tnt.service
 # Development targets
 debug: CFLAGS += -g -DDEBUG
-debug: clean $(TARGET)
+debug: clean $(TARGETS)
 release: CFLAGS += -O3 -DNDEBUG
-release: clean $(TARGET)
+release: clean $(TARGETS)
 	strip $(TARGET)
 	strip $(CTL_TARGET)
 release-check:
 	./scripts/release_check.sh
@ -83,7 +96,7 @@ release-check-strict:
 asan: CFLAGS += -g -fsanitize=address -fno-omit-frame-pointer
 asan: LDFLAGS += -fsanitize=address
-asan: clean $(TARGET)
+asan: clean $(TARGETS)
 	@echo "AddressSanitizer build complete. Run with: ASAN_OPTIONS=detect_leaks=1 ./tnt"
 valgrind: debug
@ -112,6 +125,7 @@ integration-test: all
 	@cd tests && PORT=$${PORT:-2222} ./test_basic.sh
 	@cd tests && PORT=$$(($${PORT:-2222} + 1)) ./test_exec_mode.sh
 	@cd tests && PORT=$$(($${PORT:-2222} + 2)) ./test_interactive_input.sh
 	@cd tests && ./test_tntctl_cli.sh
 anonymous-access-test: all
 	@echo "Running anonymous access tests..."
--- a/README.md
+++ b/README.md
@ -21,8 +21,9 @@ A minimalist terminal chat server with Vim-style interface over SSH.
 ```sh
 curl -sSL https://raw.githubusercontent.com/m1ngsama/TNT/main/install.sh | sh
 ```
-The installer verifies the downloaded release binary against `checksums.txt`
+The installer verifies downloaded release binaries against `checksums.txt`
-before installing it.
+before installing them. Older releases may provide only `tnt`; newer releases
 also install `tntctl`.
 **From source:**
 ```sh
@ -183,6 +184,18 @@ ssh -p 2222 chat.example.com post "/me deploys v2.0"
 **`post` identity**: the message is attributed to the SSH login name (the `user@` part of the URL, falling back to `anonymous`). In the default anonymous-access configuration there is no identity check, so any client can post as any name. Set `TNT_ACCESS_TOKEN` if you need authenticated posting.
 See [docs/INTERFACE.md](docs/INTERFACE.md) for the stable exec command
 contract, exit statuses, and JSON field definitions.
 Source and package-manager installs also include `tntctl`, a thin wrapper
 around the same SSH exec interface:
 ```sh
 tntctl chat.example.com health
 tntctl -p 2222 chat.example.com stats --json
 tntctl -l operator chat.example.com post "service notice"
 ```
 ## Development
 ### Building
@ -254,6 +267,7 @@ TNT/
 │   ├── commands.c    # COMMAND-mode command dispatch
 │   ├── exec_catalog.c # SSH exec command matching, usage, and argument shape
 │   ├── exec.c        # SSH exec command dispatch
 │   ├── tntctl.c      # local wrapper around the SSH exec interface
 │   ├── ssh_server.c  # SSH server implementation
 │   ├── bootstrap.c   # SSH authentication and session bootstrap
 │   ├── chat_room.c   # chat room logic
@ -358,6 +372,7 @@ Delete `motd.txt` to disable the MOTD.
 - [Development Guide](https://github.com/m1ngsama/TNT/wiki/Development-Guide) - Complete development manual
 - [Quick Setup](docs/EASY_SETUP.md) - 5-minute deployment guide
 - [Roadmap](docs/ROADMAP.md) - Long-term Unix/GNU direction and next stages
 - [Interface Contract](docs/INTERFACE.md) - Scriptable commands, exit statuses, and JSON fields
 - [Security Reference](docs/SECURITY_QUICKREF.md) - Security config quick reference
 - [Contributing](docs/CONTRIBUTING.md) - How to contribute
 - [Changelog](docs/CHANGELOG.md) - Version history
--- a/SECURITY.md
+++ b/SECURITY.md
@ -0,0 +1,61 @@
 # Security Policy
 ## Supported Versions
 TNT currently supports security fixes for the latest published release and the
 current `main` branch.
 | Version | Supported |
 |---|---|
 | latest release | yes |
 | `main` | best effort |
 | older releases | no |
 This policy will become stricter after TNT has a longer stable release history.
 ## Reporting a Vulnerability
 Do not open a public issue for a security vulnerability.
 Report privately through one of these paths:
 - GitHub private vulnerability reporting, when available on the repository
 - email: `contact@m1ng.space`
 Include:
 - affected version or commit
 - operating system and deployment shape
 - reproduction steps or proof of concept
 - expected impact
 - whether the issue is already public
 ## Response
 The maintainer will try to acknowledge valid reports within 7 days.  Fixes may
 land on `main` before a release is published.  For serious issues, the release
 notes will mention the security impact after users have a reasonable upgrade
 path.
 ## Scope
 In scope:
 - remote crashes or memory-safety bugs
 - authentication or access-token bypass
 - unintended file writes outside `TNT_STATE_DIR`
 - privilege escalation in packaged service configuration
 - release artifact tampering or installer verification bypass
 Out of scope:
 - denial of service from an operator intentionally disabling rate limits
 - identity spoofing in the documented anonymous-access mode
 - vulnerabilities requiring local administrator access to the host
 ## Release Integrity
 Release binaries are published with `checksums.txt`.  The installer verifies
 the selected binary against that file before installation.  Future releases
 should add a detached signature for `checksums.txt` before package recipes are
 submitted to public registries.
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@ -2,7 +2,48 @@
 ## Unreleased
 ### Added
 - Documented the stable SSH exec interface contract, including exit statuses
  and JSON field shapes for package tests, scripts, and future `tntctl` work.
 - Added a public security policy, supported-version guidance, and GitHub issue
  templates for bug reports and feature requests.
 - Added `tntctl`, a thin local wrapper around the documented SSH exec
  interface for health, stats, users, tail, post, help, and exit commands.
 ### Changed
 - `make install-systemd` now rewrites the installed unit's `ExecStart` to match
  the selected `PREFIX`/`BINDIR`, so package builds that install to `/usr`
  produce a unit pointing at `/usr/bin/tnt`.
 - Release preflight now checks the staged systemd unit path, and strict release
  checks also require a clean tree, tag-at-HEAD, changelog release section, and
  non-placeholder maintainer metadata.
 - CI and release workflows now use explicit least-privilege repository
  permissions.
 - The release guide now documents SemVer expectations, manual release review,
  smoke testing, and rollback steps.
 - Package installs now include `tntctl` and its man page alongside `tnt`.
 - SSH exec commands longer than the command buffer are now rejected with a
  usage error instead of being truncated and executed.
 - SSH exec `post` now persists the message before broadcasting or returning
  `posted`, so persistence failures are not visible as successful room events.
 - Mention and private-message bell notifications are now queued on the target
  client and flushed by that client's own session loop, so slow SSH writes do
  not block the sender's message path.
 - Private-message inbox access now uses its own mutex instead of sharing the
  SSH channel write lock, reducing unrelated contention on slow clients.
 - Client writes now check the SSH channel's remote window before writing and
  mark the client disconnected when the window is closed, avoiding the most
  direct slow-reader blocking path.
 - Room capacity and mention notification bookkeeping now follow
  `TNT_MAX_CONNECTIONS` instead of a hidden fixed 64-client array limit.
 - Updated the roadmap to reflect completed `tntctl`, stable exec contract, and
  monitoring-interface work, leaving the remaining daemon naming and runtime
  queue work explicit.
 - Strict release preflight now builds and installs from the local `vX.Y.Z` tag
  source archive, catching untracked files that would be missing from a GitHub
  source release.
 - Release documentation now creates the local tag before strict release checks,
  matching the strict gate's tag-at-HEAD requirement.
 - Split UI-language parsing from localized text lookup: `src/i18n.c` now owns
  locale/code parsing, while `src/i18n_text.c` owns the table-driven text
  catalog with coverage checks for every message ID.
--- a/docs/CICD.md
+++ b/docs/CICD.md
@ -19,37 +19,87 @@ into production or restart services on push.
 CREATING RELEASES
 -----------------
 Release policy:
  - Use SemVer-style tags: vMAJOR.MINOR.PATCH.
  - Bump PATCH for compatible bug fixes and release hardening.
  - Bump MINOR for new commands, new documented flags, JSON field additions,
    or visible user-interface behavior changes.
  - Bump MAJOR for incompatible command, config, storage, or package behavior.
  - Keep GitHub draft release review manual. Do not auto-publish releases.
  - Keep production deployment manual. Do not SSH into production from CI.
 1. Update version metadata:
   - include/common.h
   - tnt.1
   - docs/CHANGELOG.md
   - packaging/arch/PKGBUILD
   - packaging/homebrew/tnt-chat.rb
   - packaging/debian/debian/changelog
   - package checksums and maintainer metadata, when preparing public package
     recipes
 2. Run the local preflight:
   make release-check
-3. Replace package checksum placeholders and run:
+3. Commit the release changes and create a local tag.  Do not push the tag
   until strict checks pass:
   git tag v1.0.1
 4. Run strict release checks:
   make release-check-strict
-4. Create and push tag:
+   Strict mode requires the local `vX.Y.Z` tag to point at HEAD.  It also
-   git tag v1.0.1
+   builds from the tagged source archive, so it catches files that were left
   untracked and would be missing from GitHub's source archive.
 5. Push the tag:
   git push origin v1.0.1
-5. GitHub Actions automatically:
+6. GitHub Actions automatically:
-   - Builds binaries (Linux/macOS, AMD64/ARM64)
+   - Builds `tnt` and `tntctl` binaries (Linux/macOS, AMD64/ARM64)
   - Creates a draft release
   - Uploads binaries
   - Generates one `checksums.txt` file
   - Verifies that artifact architecture matches the asset name
-6. Review the draft release, smoke-test downloaded assets, then publish it
+7. Review the draft release, smoke-test downloaded assets, then publish it
   manually from GitHub.
-7. Release appears at:
+8. Release appears at:
   https://github.com/m1ngsama/TNT/releases
 RELEASE REVIEW CHECKLIST
 ------------------------
 Before publishing a draft release:
  - Confirm `git tag` points at the intended commit.
  - Download every release asset from GitHub, not from the local workspace.
  - Verify `checksums.txt` with `sha256sum -c checksums.txt`.
  - Run downloaded `tnt --version` and `tntctl --version`.
  - Start a temporary server and check:
      ssh -p 2222 server health
      ssh -p 2222 server stats --json
      ssh -p 2222 server users --json
      ssh -p 2222 operator@server post "release smoke"
      ssh -p 2222 server "tail -n 1"
  - Check runtime dynamic links (`ldd` on Linux, `otool -L` on macOS) and make
    sure `libssh` is documented for the target install path.
  - Confirm `make release-check-strict` passed after package checksums were
    replaced.
 ROLLBACK
 --------
 Production rollback stays manual:
  1. Keep the previous binary before replacing it.
  2. Stop or restart only the intended `tnt` service.
  3. Restore the previous binary if smoke checks fail.
  4. Re-run `health`, `stats --json`, and one post/tail smoke test.
 Do not overwrite `TNT_STATE_DIR` during rollback.  If a future release changes
 the message log format, its release notes must include the downgrade behavior.
 DEPLOYING TO SERVERS
 --------------------
 Deployments are operator-driven:
--- a/docs/CONTRIBUTING.md
+++ b/docs/CONTRIBUTING.md
@ -41,6 +41,7 @@ command_catalog.c → COMMAND-mode command metadata, usage, and argument shape
 commands.c       → COMMAND-mode command dispatch
 exec_catalog.c   → SSH exec command matching, usage, and argument shape
 exec.c           → SSH exec command dispatch
 tntctl.c         → local wrapper around the SSH exec interface
 ssh_server.c     → SSH listener setup
 bootstrap.c      → SSH authentication/session bootstrap
 input.c          → interactive session loop
@ -69,7 +70,7 @@ utf8.c           → UTF-8 string handling
 ## Known Limits
- Max 64 clients (MAX_CLIENTS)
+- Default 64 clients, configurable with `TNT_MAX_CONNECTIONS`
 - Max 100 messages in memory (MAX_MESSAGES)
 - Max 1024 bytes per message (MAX_MESSAGE_LEN)
 - Max 64 bytes username (MAX_USERNAME_LEN)
--- a/docs/INTERFACE.md
+++ b/docs/INTERFACE.md
@ -0,0 +1,150 @@
 # Interface Contract
 This document defines the public surfaces that scripts, package tests, and
 operators may rely on.
 TNT is still evolving toward a split `tntd` / `tntctl` model.  The stable
 control surface is the SSH exec interface exposed by the `tnt` daemon.
 `tntctl` is a thin wrapper around that same interface.
 ## Stability Scope
 Stable:
 - documented command-line flags in `tnt(1)`
 - documented environment variables in `tnt(1)`
 - SSH exec command names and argument shapes listed below
 - SSH exec exit statuses
 - JSON field names and value types for documented `--json` commands
 Not yet stable:
 - exact human-readable diagnostic wording
 - interactive TUI layout
 - on-disk message log format
 - internal module names and helper functions
 ## Exit Status
 TNT process startup and SSH exec commands use these exit statuses:
 | Code | Name | Meaning |
 |---:|---|---|
 | 0 | `TNT_EXIT_OK` | Success |
 | 1 | `TNT_EXIT_ERROR` | Runtime error, I/O error, allocation failure, persistence failure |
 | 64 | `TNT_EXIT_USAGE` | Unknown command, invalid option, invalid argument shape |
 | 69 | `TNT_EXIT_UNAVAILABLE` | Local `tntctl` SSH transport unavailable |
 | 78 | `TNT_EXIT_CONFIG` | Reserved for future local `tntctl` configuration errors |
 `64` follows the common `sysexits(3)` usage-error convention.
 ## SSH Exec Commands
 Exec commands are run through a standard SSH client:
 ```sh
 ssh -p 2222 chat.example.com health
 ssh -p 2222 chat.example.com stats --json
 ssh -p 2222 chat.example.com users --json
 ssh -p 2222 chat.example.com "tail -n 20"
 ssh -p 2222 operator@chat.example.com post "service notice"
 ```
 The same commands can be run through `tntctl`:
 ```sh
 tntctl chat.example.com health
 tntctl -p 2222 chat.example.com stats --json
 tntctl -l operator chat.example.com post "service notice"
 tntctl --host-key-checking accept-new chat.example.com users
 ```
 ### `health`
 Prints:
 ```text
 ok
 ```
 Exit status: `0` when the daemon can accept and handle exec requests.
 ### `stats [--json]`
 Text output is line-oriented key/value data:
 ```text
 status ok
 online_users 0
 message_count 0
 client_capacity 64
 active_connections 1
 uptime_seconds 12
 ```
 JSON output:
 ```json
 {
  "status": "ok",
  "online_users": 0,
  "message_count": 0,
  "client_capacity": 64,
  "active_connections": 1,
  "uptime_seconds": 12
 }
 ```
 Field names and scalar types are stable.  New fields may be added in a minor
 release.
 ### `users [--json]`
 Text output prints one username per line.
 JSON output is an array of strings:
 ```json
 ["alice", "bob"]
 ```
 ### `tail [N]` / `tail -n N`
 Prints recent in-memory messages as tab-separated lines:
 ```text
 2026-05-25T12:00:00Z	alice	hello
 ```
 The current upper bound is `MAX_MESSAGES`.  This command reads the live
 in-memory room buffer, not the full persisted log.
 ### `post MESSAGE`
 Posts a message as the SSH login name and prints:
 ```text
 posted
 ```
 In anonymous-access mode, the SSH login name is not authenticated.  Operators
 should configure `TNT_ACCESS_TOKEN` before relying on exec-post identity.
 ### `help`
 Prints a localized human-readable command summary.  It is intended for people,
 not parsers.
 ## `tntctl`
 `tntctl` preserves the command names, exit statuses, and JSON schemas above.
 It invokes the local `ssh(1)` client without a local shell.  OpenSSH transport
 failures are mapped to `TNT_EXIT_UNAVAILABLE` (`69`); remote TNT exec statuses
 are otherwise returned unchanged.
 The wrapper intentionally does not accept arbitrary SSH options or a password
 option.  It exposes only bounded host-key options:
 `--host-key-checking yes|accept-new|no` and `--known-hosts FILE`.  Use normal
 SSH configuration for jump hosts, identity files, and authentication.  If the
 server requires `TNT_ACCESS_TOKEN`, enter it through the normal SSH password
 prompt or use an SSH setup appropriate for the deployment.
--- a/docs/ROADMAP.md
+++ b/docs/ROADMAP.md
@ -17,26 +17,33 @@ This roadmap is intentionally strict. Each stage should leave the project easier
 Goal: make TNT predictable for operators, scripts, and package maintainers.
- split the current surface into `tntd` (daemon) and `tntctl` (control client)
+- ✅ introduce `tntctl` as a thin control client over the stable SSH exec surface
- keep SSH exec support, but treat it as a transport for stable commands rather than the primary API shape
+- keep SSH exec support, but treat it as a transport for stable commands rather
- define stable subcommands and exit codes for:
+  than an ad hoc command surface
 - ✅ define stable subcommands and exit codes for:
  - `health`
  - `stats`
  - `users`
  - `tail`
  - `post`
- support text and JSON output modes where machine use is likely
+- ✅ support text and JSON output modes where machine use is likely
- normalize command parsing, help text, and error reporting
+- ✅ normalize command parsing, help text, and error reporting
 - decide whether the server binary should remain `tnt` or split later into a
  separate `tntd` daemon name
 - add `--bind`, `--port`, `--state-dir`, `--public-host`, `--max-clients`, and related long options consistently
- add a man page for `tntd` and `tntctl`
+- ✅ add man pages for `tnt` and `tntctl`
 ## Stage 2: Runtime Model
 Goal: make long-running operation boring and reliable.
 - move client state to a clearer ownership model with one release path
- finish replacing ad hoc cross-thread UI mutation with per-client event delivery
+- ✅ remove cross-client SSH channel writes from mention and private-message
- add bounded outbound queues so slow clients cannot stall other users
+  notifications
 - continue replacing ad hoc cross-thread UI mutation with per-client event
  delivery
 - add bounded outbound queues so slow clients cannot stall their own session
  loop indefinitely
 - separate accept, session bootstrap, interactive I/O, and persistence concerns more cleanly
 - make room/client capacity fully runtime-configurable with no hidden compile-time ceiling
 - document hard guarantees and soft limits
@ -73,7 +80,7 @@ Goal: make public deployment manageable.
 - provide clear distinction between concurrent session limits and connection-rate limits
 - add admin-only controls for read-only mode, mute, and ban
- expose a minimal health and stats surface suitable for monitoring
+- ✅ expose a minimal health and stats surface suitable for monitoring
 - support systemd-friendly readiness and watchdog behavior
 - document recommended production defaults for public, private, and localhost-only deployments
 - tighten CI around authentication, limits, and restart behavior
@ -92,8 +99,12 @@ Goal: make regressions harder to introduce.
 These are the next changes that should happen before new feature work expands the surface area.
-1. Introduce `tntctl` and move stable command handling behind it.
+1. Decide the daemon naming path: keep `tnt` as the server binary for 1.x, or
-2. Define exit codes and JSON schemas for `health`, `stats`, `users`, `tail`, and `post`.
+   introduce `tntd` later with a compatibility plan.
-3. Add per-client outbound queues and finish untangling client-state ownership.
+2. Add per-client outbound queues and finish untangling client-state ownership.
-4. Remove the remaining hidden runtime limits and make them explicit configuration.
+3. Remove the remaining hidden runtime limits and make them explicit
-5. Add a long-running soak test that exercises idle sessions, reconnects, and slow consumers.
+   configuration.
 4. Add a long-running soak test that exercises idle sessions, reconnects, and
   slow consumers.
 5. Replace remaining release placeholders with real maintainer metadata and
   source-archive checksums when cutting a public package release.
--- a/include/client.h
+++ b/include/client.h
@ -8,6 +8,14 @@
 * success, -1 if the channel is gone or a partial write fails. */
 int client_send(client_t *client, const char *data, size_t len);
 /* Queue an audible bell for the client's own session loop to send.  This
 * avoids writing to another client's SSH channel from the sender's thread. */
 void client_queue_bell(client_t *client);
 /* Send one queued bell, if present, from the client's own session loop.
 * Returns 0 when no bell was pending or it was written successfully. */
 int client_flush_pending_bells(client_t *client);
 /* printf-style wrapper around client_send().  The formatted string must
 * fit in 2048 bytes; truncation or encoding errors return -1. */
 int client_printf(client_t *client, const char *fmt, ...);
--- a/include/commands.h
+++ b/include/commands.h
@ -15,9 +15,8 @@
 *   - Toggles client->mute_joins on `:mute-joins`
 *   - May broadcast a system rename message on `:nick`
 *
- * Reads g_room.  Caller must already hold the channel I/O serialisation
+ * Reads g_room.  Renders command output through the normal client_send()
- * established by handle_key() — this function calls back into client_send
+ * path; callers must not hold client->io_lock before dispatching. */
 * (via tui_render_command_output) which acquires client->io_lock. */
 void commands_dispatch(client_t *client);
 #endif /* COMMANDS_H */
--- a/include/common.h
+++ b/include/common.h
@ -14,6 +14,14 @@
 /* Project Metadata */
 #define TNT_VERSION "1.0.1"
 /* Public process/exec exit statuses.  TNT follows the common sysexits(3)
 * convention for usage errors while keeping runtime failures portable. */
 #define TNT_EXIT_OK 0
 #define TNT_EXIT_ERROR 1
 #define TNT_EXIT_USAGE 64
 #define TNT_EXIT_UNAVAILABLE 69
 #define TNT_EXIT_CONFIG 78
 /* Configuration constants */
 #define DEFAULT_PORT 2222
 #define MAX_MESSAGES 100
@ -21,7 +29,8 @@
 #define MAX_MESSAGE_LEN 1024
 #define MAX_EXEC_COMMAND_LEN 1024
 #define MAX_COMMAND_OUTPUT_LEN 8192
-#define MAX_CLIENTS 64
+#define DEFAULT_MAX_CLIENTS 64
 #define MAX_CONFIGURED_CLIENTS 1024
 #define LOG_FILE "messages.log"
 #define MAX_LOG_SIZE (10 * 1024 * 1024)  /* 10 MiB */
 #define HOST_KEY_FILE "host_key"
--- a/include/exec.h
+++ b/include/exec.h
@ -6,9 +6,9 @@
 /* Dispatch the non-interactive SSH exec command stored in
 * client->exec_command.  Returns the exit status to send back to the
 * SSH client:
- *   0  = success
+ *   TNT_EXIT_OK     = success
- *   1  = runtime error (I/O, OOM, persistence failure)
+ *   TNT_EXIT_ERROR  = runtime error (I/O, OOM, persistence failure)
- *  64  = usage error (unknown command, bad args)
+ *   TNT_EXIT_USAGE  = usage error (unknown command, bad args)
 *
 * Reads g_room and shared client state.  Safe to call once per
 * exec-mode session before the channel is closed. */
--- a/include/i18n.h
+++ b/include/i18n.h
@ -58,6 +58,9 @@ typedef enum {
    I18N_UNKNOWN_GUIDANCE,
    I18N_EXEC_POST_EMPTY,
    I18N_EXEC_POST_INVALID_UTF8,
    I18N_EXEC_POST_TOO_LONG,
    I18N_EXEC_POST_PERSIST_FAILED,
    I18N_EXEC_COMMAND_TOO_LONG,
    I18N_EXEC_UNKNOWN_COMMAND_FORMAT,
    I18N_TEXT_COUNT
 } i18n_text_id_t;
--- a/include/ssh_server.h
+++ b/include/ssh_server.h
@ -44,14 +44,16 @@ typedef struct client {
    int command_output_scroll;
    bool show_motd;                  /* command_output holds MOTD text */
    char exec_command[MAX_EXEC_COMMAND_LEN];
    bool exec_command_too_long;
    char ssh_login[MAX_USERNAME_LEN];
    time_t connect_time;
    time_t last_active;
    atomic_bool redraw_pending;
    _Atomic int pending_bells;       /* Bell nudges for this client's loop */
    _Atomic int unread_mentions;     /* @-mentions received since last reset */
    _Atomic int unread_whispers;     /* whispers received since last :inbox view */
-    /* Per-client whisper inbox.  Pushes serialise on io_lock; readers are
+    /* Per-client whisper inbox.  Protected separately from SSH channel I/O
-     * the client's own thread inside :inbox handling. */
+     * so slow writes do not block in-memory private-message delivery. */
    whisper_t whisper_inbox[WHISPER_INBOX_SIZE];
    int whisper_inbox_count;
    bool mute_joins;
@ -60,6 +62,7 @@ typedef struct client {
    int ref_count;                   /* Reference count for safe cleanup */
    pthread_mutex_t ref_lock;        /* Lock for ref_count */
    pthread_mutex_t io_lock;         /* Serialize SSH channel writes */
    pthread_mutex_t whisper_lock;    /* Serialize whisper inbox access */
    struct ssh_channel_callbacks_struct *channel_cb;
 } client_t;
--- a/install.sh
+++ b/install.sh
@ -45,7 +45,8 @@ case "$ARCH" in
    *) fail "Unsupported architecture: $ARCH" ;;
 esac
-BINARY="tnt-${OS}-${ARCH}"
+SERVER_BINARY="tnt-${OS}-${ARCH}"
 CTL_BINARY="tntctl-${OS}-${ARCH}"
 echo "=== TNT Installer ==="
 echo "OS: $OS"
@ -65,51 +66,81 @@ fi
 echo "Installing version: $VERSION"
 # Download
-URL="https://github.com/$REPO/releases/download/$VERSION/$BINARY"
+SERVER_URL="https://github.com/$REPO/releases/download/$VERSION/$SERVER_BINARY"
 CTL_URL="https://github.com/$REPO/releases/download/$VERSION/$CTL_BINARY"
 CHECKSUM_URL="https://github.com/$REPO/releases/download/$VERSION/checksums.txt"
-echo "Downloading from: $URL"
+echo "Downloading from: $SERVER_URL"
-TMP_FILE=$(mktemp "${TMPDIR:-/tmp}/tnt.XXXXXX")
+SERVER_TMP_FILE=$(mktemp "${TMPDIR:-/tmp}/tnt.XXXXXX")
 CTL_TMP_FILE=$(mktemp "${TMPDIR:-/tmp}/tntctl.XXXXXX")
 CHECKSUM_FILE=$(mktemp "${TMPDIR:-/tmp}/tnt-checksums.XXXXXX")
 INSTALL_CTL=0
 cleanup() {
-    rm -f "$TMP_FILE" "$CHECKSUM_FILE"
+    rm -f "$SERVER_TMP_FILE" "$CTL_TMP_FILE" "$CHECKSUM_FILE"
 }
 trap cleanup EXIT INT TERM
-curl -fsSL -o "$TMP_FILE" "$URL" || fail "Failed to download $BINARY"
+curl -fsSL -o "$SERVER_TMP_FILE" "$SERVER_URL" ||
    fail "Failed to download $SERVER_BINARY"
 echo "Downloading checksums from: $CHECKSUM_URL"
 curl -fsSL -o "$CHECKSUM_FILE" "$CHECKSUM_URL" ||
    fail "Failed to download checksums.txt"
-EXPECTED_SHA=$(awk -v name="$BINARY" '$2 == name { print $1; exit }' "$CHECKSUM_FILE")
+EXPECTED_SERVER_SHA=$(awk -v name="$SERVER_BINARY" '$2 == name { print $1; exit }' "$CHECKSUM_FILE")
-[ -n "$EXPECTED_SHA" ] || fail "No checksum entry found for $BINARY"
+[ -n "$EXPECTED_SERVER_SHA" ] || fail "No checksum entry found for $SERVER_BINARY"
 EXPECTED_CTL_SHA=$(awk -v name="$CTL_BINARY" '$2 == name { print $1; exit }' "$CHECKSUM_FILE")
-ACTUAL_SHA=$(sha256_of "$TMP_FILE") ||
+ACTUAL_SERVER_SHA=$(sha256_of "$SERVER_TMP_FILE") ||
    fail "sha256sum or shasum is required for checksum verification"
-[ "$ACTUAL_SHA" = "$EXPECTED_SHA" ] ||
+[ "$ACTUAL_SERVER_SHA" = "$EXPECTED_SERVER_SHA" ] ||
-    fail "Checksum mismatch for $BINARY"
+    fail "Checksum mismatch for $SERVER_BINARY"
-echo "Checksum verified: $ACTUAL_SHA"
+echo "Checksum verified: $SERVER_BINARY $ACTUAL_SERVER_SHA"
 if [ -n "$EXPECTED_CTL_SHA" ]; then
    echo "Downloading from: $CTL_URL"
    curl -fsSL -o "$CTL_TMP_FILE" "$CTL_URL" ||
        fail "Failed to download $CTL_BINARY"
    ACTUAL_CTL_SHA=$(sha256_of "$CTL_TMP_FILE") ||
        fail "sha256sum or shasum is required for checksum verification"
    [ "$ACTUAL_CTL_SHA" = "$EXPECTED_CTL_SHA" ] ||
        fail "Checksum mismatch for $CTL_BINARY"
    echo "Checksum verified: $CTL_BINARY $ACTUAL_CTL_SHA"
    INSTALL_CTL=1
 else
    echo "No checksum entry found for $CTL_BINARY; skipping tntctl for this release"
 fi
 # Install
-chmod +x "$TMP_FILE"
+chmod +x "$SERVER_TMP_FILE"
 [ "$INSTALL_CTL" -eq 0 ] || chmod +x "$CTL_TMP_FILE"
 if [ -d "$INSTALL_DIR" ] && [ -w "$INSTALL_DIR" ]; then
-    install -m 755 "$TMP_FILE" "$INSTALL_DIR/tnt"
+    install -m 755 "$SERVER_TMP_FILE" "$INSTALL_DIR/tnt"
    [ "$INSTALL_CTL" -eq 0 ] || install -m 755 "$CTL_TMP_FILE" "$INSTALL_DIR/tntctl"
 else
    echo "Need sudo for installation to $INSTALL_DIR"
    need_cmd sudo
    sudo mkdir -p "$INSTALL_DIR"
-    sudo install -m 755 "$TMP_FILE" "$INSTALL_DIR/tnt"
+    sudo install -m 755 "$SERVER_TMP_FILE" "$INSTALL_DIR/tnt"
    [ "$INSTALL_CTL" -eq 0 ] || sudo install -m 755 "$CTL_TMP_FILE" "$INSTALL_DIR/tntctl"
 fi
 echo ""
 if [ "$INSTALL_CTL" -eq 1 ]; then
    echo "TNT installed successfully to $INSTALL_DIR/tnt and $INSTALL_DIR/tntctl"
 else
    echo "TNT installed successfully to $INSTALL_DIR/tnt"
 fi
 echo ""
 echo "Run with:"
 echo "  tnt"
 echo ""
 echo "Or specify port:"
 echo "  PORT=3333 tnt"
 if [ "$INSTALL_CTL" -eq 1 ]; then
    echo ""
    echo "Control a server with:"
    echo "  tntctl localhost health"
 fi
--- a/packaging/README.md
+++ b/packaging/README.md
@ -10,6 +10,9 @@ any public registry.
 - `homebrew/` - Homebrew tap formula draft and maintainer notes.
 - `debian/` - Ubuntu PPA / Debian packaging notes and draft metadata.
 Package installs include both `tnt` and `tntctl`.  `tnt` is the server process;
 `tntctl` is a thin wrapper around the documented SSH exec interface.
 ## Release checklist
 1. Confirm `TNT_VERSION` in `include/common.h` and the manpage version match.
--- a/packaging/debian/README.md
+++ b/packaging/debian/README.md
@ -44,6 +44,6 @@ debuild -S
 ## Package shape
 - Binary package name: `tnt-chat`
- Installed command: `/usr/bin/tnt`
+- Installed commands: `/usr/bin/tnt`, `/usr/bin/tntctl`
 - Runtime dependency: `libssh`
 - Optional systemd unit: `/usr/lib/systemd/system/tnt.service`
--- a/packaging/homebrew/tnt-chat.rb
+++ b/packaging/homebrew/tnt-chat.rb
@ -12,10 +12,13 @@ class TntChat < Formula
    system "make", "install", "DESTDIR=#{buildpath}/stage", "PREFIX=#{prefix}"
    bin.install "#{buildpath}/stage#{prefix}/bin/tnt"
    bin.install "#{buildpath}/stage#{prefix}/bin/tntctl"
    man1.install "#{buildpath}/stage#{prefix}/share/man/man1/tnt.1"
    man1.install "#{buildpath}/stage#{prefix}/share/man/man1/tntctl.1"
  end
  test do
    assert_match version.to_s, shell_output("#{bin}/tnt --version")
    assert_match version.to_s, shell_output("#{bin}/tntctl --version")
  end
 end
--- a/scripts/release_check.sh
+++ b/scripts/release_check.sh
@ -22,7 +22,9 @@ Environment:
  RUN_INTEGRATION=1  also run full make test
  PORT=12720         base port for integration tests
-Strict checks additionally require real package checksums and a local vX.Y.Z tag.
+Strict checks additionally require a clean tree, a vX.Y.Z tag at HEAD, a
 matching changelog release section, real package checksums, and non-placeholder
 maintainer metadata, then build from the tagged source archive.
 USAGE
 }
@ -62,6 +64,8 @@ version=$(sed -n 's/^#define TNT_VERSION "\([^"]*\)".*/\1/p' include/common.h)
 step "checking version metadata for $version"
 grep -q "\"TNT $version\"" tnt.1 ||
    fail "tnt.1 does not mention TNT $version"
 grep -q "\"TNT $version\"" tntctl.1 ||
    fail "tntctl.1 does not mention TNT $version"
 grep -q "^pkgver=$version$" packaging/arch/PKGBUILD ||
    fail "packaging/arch/PKGBUILD pkgver does not match $version"
 grep -q "pkgver = $version" packaging/arch/.SRCINFO ||
@ -88,11 +92,25 @@ make
 actual_version=$(./tnt --version)
 [ "$actual_version" = "tnt $version" ] ||
    fail "binary version mismatch: expected 'tnt $version', got '$actual_version'"
 tntctl_version=$(./tntctl --version)
 [ "$tntctl_version" = "tntctl $version" ] ||
    fail "control binary version mismatch: expected 'tntctl $version', got '$tntctl_version'"
 step "running unit tests"
 make -C tests/unit clean
 make -C tests/unit run
 step "checking client I/O ownership boundaries"
 ! grep -R "client_send(target" src include >/dev/null ||
    fail "cross-client target writes must be queued through client_queue_bell"
 ! grep -R "client_send(targets" src include >/dev/null ||
    fail "cross-client target-array writes must be queued through client_queue_bell"
 ! grep -n "pthread_mutex_lock(&.*->io_lock)" src/commands.c >/dev/null ||
    fail "commands.c must not use SSH io_lock for in-memory command state"
 if grep -R "ssh_channel_write" src include | grep -v "^src/client.c:" >/dev/null; then
    fail "raw SSH channel writes must stay inside src/client.c"
 fi
 if [ "${RUN_INTEGRATION:-0}" = "1" ]; then
    step "running full integration tests"
    make test PORT="${PORT:-12720}"
@ -109,9 +127,13 @@ make DESTDIR="$tmpdir" PREFIX=/usr install
 make DESTDIR="$tmpdir" PREFIX=/usr install-systemd
 [ -x "$tmpdir/usr/bin/tnt" ] || fail "missing executable: /usr/bin/tnt"
 [ -x "$tmpdir/usr/bin/tntctl" ] || fail "missing executable: /usr/bin/tntctl"
 [ -f "$tmpdir/usr/share/man/man1/tnt.1" ] || fail "missing manpage: /usr/share/man/man1/tnt.1"
 [ -f "$tmpdir/usr/share/man/man1/tntctl.1" ] || fail "missing manpage: /usr/share/man/man1/tntctl.1"
 [ -f "$tmpdir/usr/lib/systemd/system/tnt.service" ] ||
    fail "missing systemd unit: /usr/lib/systemd/system/tnt.service"
 grep -q "^ExecStart=/usr/bin/tnt$" "$tmpdir/usr/lib/systemd/system/tnt.service" ||
    fail "systemd unit ExecStart does not match PREFIX=/usr install path"
 step "checking installer syntax"
 sh -n install.sh
@ -137,14 +159,61 @@ fi
 if [ "$STRICT" -eq 1 ]; then
    step "checking strict release gates"
    [ -z "$(git status --short)" ] ||
        fail "working tree must be clean for strict release"
    git rev-parse -q --verify "refs/tags/v$version" >/dev/null ||
        fail "missing local tag v$version"
    [ "$(git rev-parse "refs/tags/v$version^{}")" = "$(git rev-parse HEAD)" ] ||
        fail "local tag v$version does not point at HEAD"
    grep -q "^## $version " docs/CHANGELOG.md ||
        fail "docs/CHANGELOG.md does not contain a release section for $version"
    ! grep -q "sha256sums=('SKIP')" packaging/arch/PKGBUILD ||
        fail "replace PKGBUILD sha256sums before strict release"
    ! grep -q "sha256sums = SKIP" packaging/arch/.SRCINFO ||
        fail "replace .SRCINFO sha256sums before strict release"
    ! grep -q "REPLACE_WITH_RELEASE_TARBALL_SHA256" packaging/homebrew/tnt-chat.rb ||
        fail "replace Homebrew sha256 before strict release"
-    git rev-parse -q --verify "refs/tags/v$version" >/dev/null ||
+    ! grep -R "REPLACE_WITH_EMAIL" packaging/arch packaging/debian >/dev/null ||
-        fail "missing local tag v$version"
+        fail "replace maintainer email placeholders before strict release"
    step "checking tagged source archive"
    archive="$tmpdir/tnt-$version-source.tar.gz"
    archive_extract="$tmpdir/source"
    archive_install="$tmpdir/source-install"
    archive_root="$archive_extract/TNT-$version"
    git archive --format=tar.gz --prefix="TNT-$version/" \
        -o "$archive" "refs/tags/v$version"
    mkdir -p "$archive_extract"
    tar -xzf "$archive" -C "$archive_extract"
    [ -f "$archive_root/src/tntctl.c" ] ||
        fail "tagged source archive is missing src/tntctl.c"
    [ -f "$archive_root/tnt.1" ] ||
        fail "tagged source archive is missing tnt.1"
    [ -f "$archive_root/tntctl.1" ] ||
        fail "tagged source archive is missing tntctl.1"
    [ -f "$archive_root/LICENSE" ] ||
        fail "tagged source archive is missing LICENSE"
    (
        cd "$archive_root"
        make
        make DESTDIR="$archive_install" PREFIX=/usr install
        make DESTDIR="$archive_install" PREFIX=/usr install-systemd
    )
    [ -x "$archive_install/usr/bin/tnt" ] ||
        fail "tagged source install is missing /usr/bin/tnt"
    [ -x "$archive_install/usr/bin/tntctl" ] ||
        fail "tagged source install is missing /usr/bin/tntctl"
    [ -f "$archive_install/usr/share/man/man1/tnt.1" ] ||
        fail "tagged source install is missing tnt.1"
    [ -f "$archive_install/usr/share/man/man1/tntctl.1" ] ||
        fail "tagged source install is missing tntctl.1"
    grep -q "^ExecStart=/usr/bin/tnt$" \
        "$archive_install/usr/lib/systemd/system/tnt.service" ||
        fail "tagged source systemd unit ExecStart does not match /usr/bin/tnt"
 fi
 step "release preflight passed"
--- a/src/bootstrap.c
+++ b/src/bootstrap.c
@ -25,6 +25,7 @@ typedef struct {
    int pty_width;
    int pty_height;
    char exec_command[MAX_EXEC_COMMAND_LEN];
    bool exec_command_too_long;
    bool auth_success;
    int auth_attempts;
    bool channel_ready;  /* Set when shell/exec request received */
@ -294,9 +295,14 @@ static int channel_exec_request(ssh_session session, ssh_channel channel,
    /* Store exec command */
    if (command) {
        if (strlen(command) >= sizeof(ctx->exec_command)) {
            ctx->exec_command_too_long = true;
            ctx->exec_command[0] = '\0';
        } else {
            strncpy(ctx->exec_command, command, sizeof(ctx->exec_command) - 1);
            ctx->exec_command[sizeof(ctx->exec_command) - 1] = '\0';
        }
    }
    /* Mark channel as ready */
    ctx->channel_ready = true;
@ -363,6 +369,7 @@ void *bootstrap_run(void *arg) {
    ctx->pty_width = 80;
    ctx->pty_height = 24;
    ctx->exec_command[0] = '\0';
    ctx->exec_command_too_long = false;
    ctx->requested_user[0] = '\0';
    ctx->auth_success = false;
    ctx->auth_attempts = 0;
@ -451,6 +458,7 @@ void *bootstrap_run(void *arg) {
    client->ref_count = 1;
    pthread_mutex_init(&client->ref_lock, NULL);
    pthread_mutex_init(&client->io_lock, NULL);
    pthread_mutex_init(&client->whisper_lock, NULL);
    if (ctx->requested_user[0] != '\0') {
        strncpy(client->ssh_login, ctx->requested_user,
@ -466,6 +474,7 @@ void *bootstrap_run(void *arg) {
                sizeof(client->exec_command) - 1);
        client->exec_command[sizeof(client->exec_command) - 1] = '\0';
    }
    client->exec_command_too_long = ctx->exec_command_too_long;
    /* Add a ref for the channel callbacks (eof/close/window_change) so the
     * client_t outlives any in-flight callback invocation. */
--- a/src/chat_room.c
+++ b/src/chat_room.c
@ -4,19 +4,8 @@
 chat_room_t *g_room = NULL;
 static int room_capacity_from_env(void) {
-    const char *env = getenv("TNT_MAX_CONNECTIONS");
+    return env_int("TNT_MAX_CONNECTIONS", DEFAULT_MAX_CLIENTS, 1,
-
+                   MAX_CONFIGURED_CLIENTS);
    if (!env || env[0] == '\0') {
        return MAX_CLIENTS;
    }
    char *end;
    long capacity = strtol(env, &end, 10);
    if (*end != '\0' || capacity < 1 || capacity > 1024) {
        return MAX_CLIENTS;
    }
    return (int)capacity;
 }
 /* Initialize chat room */
--- a/src/client.c
+++ b/src/client.c
@ -9,6 +9,13 @@
 #include <stdio.h>
 #include <stdlib.h>
 static int client_send_fail(client_t *client) {
    if (client) {
        client->connected = false;
    }
    return -1;
 }
 /* Send data to client via SSH channel */
 int client_send(client_t *client, const char *data, size_t len) {
    size_t total = 0;
@ -24,11 +31,21 @@ int client_send(client_t *client, const char *data, size_t len) {
    while (total < len) {
        size_t remaining = len - total;
        uint32_t window = ssh_channel_window_size(client->channel);
        if (window == 0) {
            pthread_mutex_unlock(&client->io_lock);
            return client_send_fail(client);
        }
        uint32_t chunk = (remaining > 32768) ? 32768 : (uint32_t)remaining;
        if (chunk > window) {
            chunk = window;
        }
        int sent = ssh_channel_write(client->channel, data + total, chunk);
        if (sent <= 0) {
            pthread_mutex_unlock(&client->io_lock);
-            return -1;
+            return client_send_fail(client);
        }
        total += (size_t)sent;
    }
@ -41,6 +58,23 @@ int client_send(client_t *client, const char *data, size_t len) {
    return 0;
 }
 void client_queue_bell(client_t *client) {
    if (!client) return;
    atomic_store(&client->pending_bells, 1);
    client->redraw_pending = true;
 }
 int client_flush_pending_bells(client_t *client) {
    if (!client) return 0;
    if (atomic_exchange(&client->pending_bells, 0) <= 0) {
        return 0;
    }
    return client_send(client, "\a", 1);
 }
 void client_addref(client_t *client) {
    if (!client) return;
    pthread_mutex_lock(&client->ref_lock);
@ -75,6 +109,7 @@ void client_release(client_t *client) {
            free(client->channel_cb);
        }
        pthread_mutex_destroy(&client->io_lock);
        pthread_mutex_destroy(&client->whisper_lock);
        pthread_mutex_destroy(&client->ref_lock);
        free(client);
    }
--- a/src/commands.c
+++ b/src/commands.c
@ -199,9 +199,9 @@ void commands_dispatch(client_t *client) {
            pthread_rwlock_unlock(&g_room->lock);
            if (target) {
-                /* Push into recipient's inbox.  io_lock serialises so two
+                /* Push into recipient's inbox.  whisper_lock serialises so
-                 * senders to the same recipient don't tear the ring. */
+                 * two senders to the same recipient don't tear the ring. */
-                pthread_mutex_lock(&target->io_lock);
+                pthread_mutex_lock(&target->whisper_lock);
                int slot;
                if (target->whisper_inbox_count < WHISPER_INBOX_SIZE) {
                    slot = target->whisper_inbox_count++;
@ -219,13 +219,12 @@ void commands_dispatch(client_t *client) {
                snprintf(target->whisper_inbox[slot].content,
                         sizeof(target->whisper_inbox[slot].content),
                         "%s", rest);
-                pthread_mutex_unlock(&target->io_lock);
+                pthread_mutex_unlock(&target->whisper_lock);
                target->unread_whispers++;
                target->redraw_pending = true;
                /* Audible nudge — the title bar ✉ counter (UX-11 style)
                 * carries the persistent signal. */
-                client_send(target, "\a", 1);
+                client_queue_bell(target);
                client_release(target);
            }
@ -243,15 +242,15 @@ void commands_dispatch(client_t *client) {
        }
    } else if (command_id == TNT_COMMAND_INBOX) {
-        /* Snapshot the inbox under io_lock so a concurrent sender doesn't
+        /* Snapshot the inbox under whisper_lock so a concurrent sender doesn't
         * tear what we're rendering.  Counter reset happens after copy. */
        whisper_t snapshot[WHISPER_INBOX_SIZE];
        int snap_count;
-        pthread_mutex_lock(&client->io_lock);
+        pthread_mutex_lock(&client->whisper_lock);
        snap_count = client->whisper_inbox_count;
        memcpy(snapshot, client->whisper_inbox,
               snap_count * sizeof(whisper_t));
-        pthread_mutex_unlock(&client->io_lock);
+        pthread_mutex_unlock(&client->whisper_lock);
        client->unread_whispers = 0;
        buffer_appendf(output, sizeof(output), &pos,
--- a/src/exec.c
+++ b/src/exec.c
@ -123,7 +123,8 @@ static int exec_command_help(client_t *client) {
    help_text[0] = '\0';
    exec_catalog_append_help(help_text, sizeof(help_text), &pos,
                             client->ui_lang);
-    return client_send(client, help_text, pos) == 0 ? 0 : 1;
+    return client_send(client, help_text, pos) == 0 ? TNT_EXIT_OK
                                                   : TNT_EXIT_ERROR;
 }
 static int exec_command_usage(client_t *client, tnt_exec_command_id_t id) {
@ -134,12 +135,13 @@ static int exec_command_usage(client_t *client, tnt_exec_command_id_t id) {
    exec_catalog_append_usage(usage, sizeof(usage), &pos, id,
                              client->ui_lang);
    client_printf(client, "%s", usage);
-    return 64;
+    return TNT_EXIT_USAGE;
 }
 static int exec_command_health(client_t *client) {
    static const char ok[] = "ok\n";
-    return client_send(client, ok, sizeof(ok) - 1) == 0 ? 0 : 1;
+    return client_send(client, ok, sizeof(ok) - 1) == 0 ? TNT_EXIT_OK
                                                       : TNT_EXIT_ERROR;
 }
 static int exec_command_users(client_t *client, bool json) {
@ -157,7 +159,7 @@ static int exec_command_users(client_t *client, bool json) {
        if (!usernames) {
            pthread_rwlock_unlock(&g_room->lock);
            client_printf(client, "users: out of memory\n");
-            return 1;
+            return TNT_EXIT_ERROR;
        }
        for (int i = 0; i < count; i++) {
@ -177,7 +179,7 @@ static int exec_command_users(client_t *client, bool json) {
    if (!output) {
        free(usernames);
        client_printf(client, "users: out of memory\n");
-        return 1;
+        return TNT_EXIT_ERROR;
    }
    if (json) {
@ -195,7 +197,7 @@ static int exec_command_users(client_t *client, bool json) {
        }
    }
-    rc = client_send(client, output, pos) == 0 ? 0 : 1;
+    rc = client_send(client, output, pos) == 0 ? TNT_EXIT_OK : TNT_EXIT_ERROR;
    free(output);
    free(usernames);
    return rc;
@ -243,10 +245,11 @@ static int exec_command_stats(client_t *client, bool json) {
    if (len < 0 || len >= (int)sizeof(buffer)) {
        client_printf(client, "stats: output overflow\n");
-        return 1;
+        return TNT_EXIT_ERROR;
    }
-    return client_send(client, buffer, (size_t)len) == 0 ? 0 : 1;
+    return client_send(client, buffer, (size_t)len) == 0 ? TNT_EXIT_OK
                                                        : TNT_EXIT_ERROR;
 }
 static int parse_tail_count(const char *args, int *count) {
@ -316,7 +319,7 @@ static int exec_command_tail(client_t *client, const char *args) {
        if (!snapshot) {
            pthread_rwlock_unlock(&g_room->lock);
            client_printf(client, "tail: out of memory\n");
-            return 1;
+            return TNT_EXIT_ERROR;
        }
        memcpy(snapshot, &g_room->messages[start], (size_t)count * sizeof(message_t));
    }
@ -328,7 +331,7 @@ static int exec_command_tail(client_t *client, const char *args) {
    if (!output) {
        free(snapshot);
        client_printf(client, "tail: out of memory\n");
-        return 1;
+        return TNT_EXIT_ERROR;
    }
    for (int i = 0; i < count; i++) {
@ -338,7 +341,7 @@ static int exec_command_tail(client_t *client, const char *args) {
                       timestamp, snapshot[i].username, snapshot[i].content);
    }
-    rc = client_send(client, output, pos) == 0 ? 0 : 1;
+    rc = client_send(client, output, pos) == 0 ? TNT_EXIT_OK : TNT_EXIT_ERROR;
    free(output);
    free(snapshot);
    return rc;
@ -355,6 +358,12 @@ static int exec_command_post(client_t *client, const char *args) {
        return exec_command_usage(client, TNT_EXEC_COMMAND_POST);
    }
    if (strlen(args) >= sizeof(content)) {
        client_printf(client, "%s",
                      i18n_text(client->ui_lang, I18N_EXEC_POST_TOO_LONG));
        return TNT_EXIT_USAGE;
    }
    strncpy(content, args, sizeof(content) - 1);
    content[sizeof(content) - 1] = '\0';
    trim_ascii_whitespace(content);
@ -362,14 +371,14 @@ static int exec_command_post(client_t *client, const char *args) {
    if (content[0] == '\0') {
        client_printf(client, "%s",
                      i18n_text(client->ui_lang, I18N_EXEC_POST_EMPTY));
-        return 64;
+        return TNT_EXIT_USAGE;
    }
    if (!utf8_is_valid_string(content)) {
        client_printf(client, "%s",
                      i18n_text(client->ui_lang,
                                I18N_EXEC_POST_INVALID_UTF8));
-        return 1;
+        return TNT_EXIT_ERROR;
    }
    resolve_exec_username(client, username, sizeof(username));
@ -388,18 +397,22 @@ static int exec_command_post(client_t *client, const char *args) {
        msg.content[sizeof(msg.content) - 1] = '\0';
    }
    room_broadcast(g_room, &msg);
    if (client_send(client, "posted\n", 7) != 0) {
        return 1;
    }
    notify_mentions(msg.content, client);
    if (message_save(&msg) < 0) {
        fprintf(stderr, "post: failed to persist message\n");
-        return 1;
+        client_printf(client, "%s",
                      i18n_text(client->ui_lang,
                                I18N_EXEC_POST_PERSIST_FAILED));
        return TNT_EXIT_ERROR;
    }
-    return 0;
+    room_broadcast(g_room, &msg);
    notify_mentions(msg.content, client);
    if (client_send(client, "posted\n", 7) != 0) {
        return TNT_EXIT_ERROR;
    }
    return TNT_EXIT_OK;
 }
 int exec_dispatch(client_t *client) {
@ -407,6 +420,13 @@ int exec_dispatch(client_t *client) {
    tnt_exec_command_id_t command_id;
    const char *args = NULL;
    if (client->exec_command_too_long) {
        client_printf(client, "%s",
                      i18n_text(client->ui_lang,
                                I18N_EXEC_COMMAND_TOO_LONG));
        return TNT_EXIT_USAGE;
    }
    strncpy(command_copy, client->exec_command, sizeof(command_copy) - 1);
    command_copy[sizeof(command_copy) - 1] = '\0';
    trim_ascii_whitespace(command_copy);
@ -434,7 +454,7 @@ int exec_dispatch(client_t *client) {
            case TNT_EXEC_COMMAND_POST:
                return exec_command_post(client, args);
            case TNT_EXEC_COMMAND_EXIT:
-                return 0;
+                return TNT_EXIT_OK;
        }
    }
@ -448,5 +468,5 @@ int exec_dispatch(client_t *client) {
                  i18n_text(client->ui_lang,
                            I18N_EXEC_UNKNOWN_COMMAND_FORMAT),
                  command_copy);
-    return 64;
+    return TNT_EXIT_USAGE;
 }
--- a/src/i18n_text.c
+++ b/src/i18n_text.c
@ -193,6 +193,18 @@ static const i18n_string_t text_catalog[I18N_TEXT_COUNT] = {
        "post: invalid UTF-8 input\n",
        "post: 输入不是有效 UTF-8\n"
    ),
    [I18N_EXEC_POST_TOO_LONG] = I18N_STRING(
        "post: message too long\n",
        "post: 消息过长\n"
    ),
    [I18N_EXEC_POST_PERSIST_FAILED] = I18N_STRING(
        "post: failed to persist message\n",
        "post: 消息持久化失败\n"
    ),
    [I18N_EXEC_COMMAND_TOO_LONG] = I18N_STRING(
        "exec: command too long\n",
        "exec: 命令过长\n"
    ),
    [I18N_EXEC_UNKNOWN_COMMAND_FORMAT] = I18N_STRING(
        "Unknown command: %s\n",
        "未知命令: %s\n"
--- a/src/input.c
+++ b/src/input.c
@ -134,9 +134,17 @@ static int read_username(client_t *client) {
 void notify_mentions(const char *content, const client_t *sender) {
    pthread_rwlock_rdlock(&g_room->lock);
    int count = g_room->client_count;
-    client_t *targets[MAX_CLIENTS];
+    client_t **targets = NULL;
    int target_count = 0;
    if (count > 0) {
        targets = calloc((size_t)count, sizeof(*targets));
        if (!targets) {
            pthread_rwlock_unlock(&g_room->lock);
            return;
        }
    }
    for (int i = 0; i < count; i++) {
        client_t *c = g_room->clients[i];
        if (c == sender) continue;
@ -150,11 +158,11 @@ void notify_mentions(const char *content, const client_t *sender) {
    pthread_rwlock_unlock(&g_room->lock);
    for (int i = 0; i < target_count; i++) {
        client_send(targets[i], "\a", 1);
        targets[i]->unread_mentions++;
-        targets[i]->redraw_pending = true;
+        client_queue_bell(targets[i]);
        client_release(targets[i]);
    }
    free(targets);
 }
 static int read_channel_exact(client_t *client, char *buf, size_t len,
@ -731,7 +739,7 @@ void input_run_session(client_t *client) {
    client->last_active = time(NULL);
    /* Check for exec command */
-    if (client->exec_command[0] != '\0') {
+    if (client->exec_command[0] != '\0' || client->exec_command_too_long) {
        int exit_status = exec_dispatch(client);
        ssh_channel_request_send_exit_status(client->channel, exit_status);
        ssh_channel_send_eof(client->channel);
@ -811,6 +819,10 @@ main_loop:
                break;
            }
            if (client_flush_pending_bells(client) != 0) {
                break;
            }
            if (current_update_seq != seen_update_seq) {
                seen_update_seq = current_update_seq;
                room_updated = true;
--- a/src/main.c
+++ b/src/main.c
@ -41,7 +41,7 @@ int main(int argc, char **argv) {
            if (*end != '\0' || val <= 0 || val > 65535) {
                fprintf(stderr, cli_text_invalid_port_format(lang),
                        argv[i + 1]);
-                return 1;
+                return TNT_EXIT_USAGE;
            }
            port = (int)val;
            i++;
@ -49,23 +49,23 @@ int main(int argc, char **argv) {
                    strcmp(argv[i], "--state-dir") == 0) && i + 1 < argc) {
            if (setenv("TNT_STATE_DIR", argv[i + 1], 1) != 0) {
                perror("setenv TNT_STATE_DIR");
-                return 1;
+                return TNT_EXIT_ERROR;
            }
            i++;
        } else if (strcmp(argv[i], "-V") == 0 || strcmp(argv[i], "--version") == 0) {
            printf("tnt %s\n", TNT_VERSION);
-            return 0;
+            return TNT_EXIT_OK;
        } else if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "--help") == 0) {
            char output[2048] = {0};
            size_t pos = 0;
            cli_text_append_help(output, sizeof(output), &pos, argv[0], lang);
            fputs(output, stdout);
-            return 0;
+            return TNT_EXIT_OK;
        } else {
            fprintf(stderr, cli_text_unknown_option_format(lang), argv[i]);
            fprintf(stderr, cli_text_short_usage_format(lang), argv[0]);
-            return 1;
+            return TNT_EXIT_USAGE;
        }
    }
@ -77,7 +77,7 @@ int main(int argc, char **argv) {
    /* Initialize subsystems */
    if (tnt_ensure_state_dir() < 0) {
        fprintf(stderr, "Failed to create state directory: %s\n", tnt_state_dir());
-        return 1;
+        return TNT_EXIT_ERROR;
    }
    message_init();
@ -86,14 +86,14 @@ int main(int argc, char **argv) {
    g_room = room_create();
    if (!g_room) {
        fprintf(stderr, "Failed to create chat room\n");
-        return 1;
+        return TNT_EXIT_ERROR;
    }
    /* Initialize server */
    if (ssh_server_init(port) < 0) {
        fprintf(stderr, "Failed to initialize server\n");
        room_destroy(g_room);
-        return 1;
+        return TNT_EXIT_ERROR;
    }
    /* Start server (blocking) */
--- a/src/tntctl.c
+++ b/src/tntctl.c
@ -0,0 +1,296 @@
 #include "common.h"
 #include <ctype.h>
 #include <errno.h>
 #include <stdio.h>
 #include <sys/wait.h>
 #include <unistd.h>
 static void print_usage(FILE *stream) {
    fprintf(stream,
            "Usage: tntctl [options] host command [args...]\n"
            "\n"
            "Options:\n"
            "  -p, --port PORT        SSH port (default: 2222)\n"
            "  -l, --login USER       SSH login name for exec identity\n"
            "  --host-key-checking MODE\n"
            "                         OpenSSH host-key mode: yes, accept-new, no\n"
            "  --known-hosts FILE     OpenSSH known_hosts file\n"
            "  -V, --version          Print version and exit\n"
            "  -h, --help             Print this help and exit\n"
            "\n"
            "Commands mirror the TNT SSH exec interface: health, stats, users,\n"
            "tail, post, help, and exit.\n");
 }
 static bool is_valid_port(const char *value) {
    char *end = NULL;
    long port;
    if (!value || value[0] == '\0') {
        return false;
    }
    errno = 0;
    port = strtol(value, &end, 10);
    return errno == 0 && end && *end == '\0' && port > 0 && port <= 65535;
 }
 static bool is_safe_ssh_token(const char *value) {
    const unsigned char *p = (const unsigned char *)value;
    if (!value || value[0] == '\0' || value[0] == '-') {
        return true;
    }
    while (*p) {
        if (isspace(*p) || iscntrl(*p) || *p == ';' || *p == '&' ||
            *p == '|' || *p == '`' || *p == '$' || *p == '<' ||
            *p == '>' || *p == '\\') {
            return true;
        }
        p++;
    }
    return false;
 }
 static bool has_newline(const char *value) {
    const char *p = value;
    while (p && *p) {
        if (*p == '\n' || *p == '\r') {
            return true;
        }
        p++;
    }
    return false;
 }
 static bool is_host_key_checking_mode(const char *value) {
    return value &&
           (strcmp(value, "yes") == 0 ||
            strcmp(value, "accept-new") == 0 ||
            strcmp(value, "no") == 0);
 }
 static bool is_known_exec_command(const char *command) {
    return command &&
           (strcmp(command, "health") == 0 ||
            strcmp(command, "stats") == 0 ||
            strcmp(command, "users") == 0 ||
            strcmp(command, "tail") == 0 ||
            strcmp(command, "post") == 0 ||
            strcmp(command, "help") == 0 ||
            strcmp(command, "exit") == 0);
 }
 static int build_remote_command(char *buffer, size_t buf_size, int argc,
                                char **argv, int first_arg) {
    size_t pos = 0;
    if (first_arg >= argc) {
        return -1;
    }
    buffer[0] = '\0';
    for (int i = first_arg; i < argc; i++) {
        size_t len;
        if (has_newline(argv[i])) {
            return -1;
        }
        len = strlen(argv[i]);
        if (pos + len + (i > first_arg ? 1u : 0u) >= buf_size) {
            return -1;
        }
        if (i > first_arg) {
            buffer[pos++] = ' ';
        }
        memcpy(buffer + pos, argv[i], len);
        pos += len;
        buffer[pos] = '\0';
    }
    return 0;
 }
 static int run_ssh(char **ssh_argv) {
    pid_t pid = fork();
    int status;
    if (pid < 0) {
        perror("tntctl: fork");
        return TNT_EXIT_ERROR;
    }
    if (pid == 0) {
        execvp("ssh", ssh_argv);
        perror("tntctl: ssh");
        _exit(TNT_EXIT_UNAVAILABLE);
    }
    while (waitpid(pid, &status, 0) < 0) {
        if (errno != EINTR) {
            perror("tntctl: waitpid");
            return TNT_EXIT_ERROR;
        }
    }
    if (WIFEXITED(status)) {
        int rc = WEXITSTATUS(status);
        return rc == 255 ? TNT_EXIT_UNAVAILABLE : rc;
    }
    if (WIFSIGNALED(status)) {
        return 128 + WTERMSIG(status);
    }
    return TNT_EXIT_ERROR;
 }
 int main(int argc, char **argv) {
    const char *port = "2222";
    const char *login = NULL;
    const char *host_key_checking = NULL;
    const char *known_hosts = NULL;
    char host_key_option[64];
    char known_hosts_option[1024];
    int i;
    const char *host;
    char destination[512];
    char remote_command[MAX_EXEC_COMMAND_LEN];
    char **ssh_argv = NULL;
    int ssh_argc = 0;
    int rc;
    for (i = 1; i < argc; i++) {
        if (strcmp(argv[i], "--") == 0) {
            i++;
            break;
        } else if (strcmp(argv[i], "-h") == 0 ||
                   strcmp(argv[i], "--help") == 0) {
            print_usage(stdout);
            return TNT_EXIT_OK;
        } else if (strcmp(argv[i], "-V") == 0 ||
                   strcmp(argv[i], "--version") == 0) {
            printf("tntctl %s\n", TNT_VERSION);
            return TNT_EXIT_OK;
        } else if (strcmp(argv[i], "-p") == 0 ||
                   strcmp(argv[i], "--port") == 0) {
            if (i + 1 >= argc || !is_valid_port(argv[i + 1])) {
                fprintf(stderr, "tntctl: invalid port\n");
                return TNT_EXIT_USAGE;
            }
            port = argv[++i];
        } else if (strcmp(argv[i], "-l") == 0 ||
                   strcmp(argv[i], "--login") == 0) {
            if (i + 1 >= argc || is_safe_ssh_token(argv[i + 1]) ||
                strchr(argv[i + 1], '@')) {
                fprintf(stderr, "tntctl: invalid login\n");
                return TNT_EXIT_USAGE;
            }
            login = argv[++i];
        } else if (strcmp(argv[i], "--host-key-checking") == 0) {
            if (i + 1 >= argc || !is_host_key_checking_mode(argv[i + 1])) {
                fprintf(stderr, "tntctl: invalid host-key checking mode\n");
                return TNT_EXIT_USAGE;
            }
            host_key_checking = argv[++i];
        } else if (strcmp(argv[i], "--known-hosts") == 0) {
            if (i + 1 >= argc || argv[i + 1][0] == '\0' ||
                has_newline(argv[i + 1])) {
                fprintf(stderr, "tntctl: invalid known_hosts path\n");
                return TNT_EXIT_USAGE;
            }
            known_hosts = argv[++i];
        } else if (argv[i][0] == '-') {
            fprintf(stderr, "tntctl: unknown option: %s\n", argv[i]);
            print_usage(stderr);
            return TNT_EXIT_USAGE;
        } else {
            break;
        }
    }
    if (i >= argc) {
        fprintf(stderr, "tntctl: missing host\n");
        print_usage(stderr);
        return TNT_EXIT_USAGE;
    }
    host = argv[i++];
    if (is_safe_ssh_token(host)) {
        fprintf(stderr, "tntctl: invalid host\n");
        return TNT_EXIT_USAGE;
    }
    if (login && strchr(host, '@')) {
        fprintf(stderr, "tntctl: use either --login or user@host, not both\n");
        return TNT_EXIT_USAGE;
    }
    if (i >= argc || !is_known_exec_command(argv[i])) {
        fprintf(stderr, "tntctl: unknown or missing command\n");
        return TNT_EXIT_USAGE;
    }
    if (build_remote_command(remote_command, sizeof(remote_command), argc,
                             argv, i) < 0) {
        fprintf(stderr, "tntctl: invalid or too-long command\n");
        return TNT_EXIT_USAGE;
    }
    if (login) {
        int n = snprintf(destination, sizeof(destination), "%s@%s", login,
                         host);
        if (n < 0 || n >= (int)sizeof(destination)) {
            fprintf(stderr, "tntctl: destination too long\n");
            return TNT_EXIT_USAGE;
        }
    } else {
        int n = snprintf(destination, sizeof(destination), "%s", host);
        if (n < 0 || n >= (int)sizeof(destination)) {
            fprintf(stderr, "tntctl: destination too long\n");
            return TNT_EXIT_USAGE;
        }
    }
    if (destination[0] == '-') {
        fprintf(stderr, "tntctl: invalid destination\n");
        return TNT_EXIT_USAGE;
    }
    ssh_argv = calloc((size_t)argc * 2u + 8u, sizeof(*ssh_argv));
    if (!ssh_argv) {
        fprintf(stderr, "tntctl: out of memory\n");
        return TNT_EXIT_ERROR;
    }
    ssh_argv[ssh_argc++] = "ssh";
    ssh_argv[ssh_argc++] = "-p";
    ssh_argv[ssh_argc++] = (char *)port;
    if (host_key_checking) {
        int n = snprintf(host_key_option, sizeof(host_key_option),
                         "StrictHostKeyChecking=%s", host_key_checking);
        if (n < 0 || n >= (int)sizeof(host_key_option)) {
            fprintf(stderr, "tntctl: host-key option too long\n");
            free(ssh_argv);
            return TNT_EXIT_USAGE;
        }
        ssh_argv[ssh_argc++] = "-o";
        ssh_argv[ssh_argc++] = host_key_option;
    }
    if (known_hosts) {
        int n = snprintf(known_hosts_option, sizeof(known_hosts_option),
                         "UserKnownHostsFile=%s", known_hosts);
        if (n < 0 || n >= (int)sizeof(known_hosts_option)) {
            fprintf(stderr, "tntctl: known_hosts option too long\n");
            free(ssh_argv);
            return TNT_EXIT_USAGE;
        }
        ssh_argv[ssh_argc++] = "-o";
        ssh_argv[ssh_argc++] = known_hosts_option;
    }
    ssh_argv[ssh_argc++] = destination;
    ssh_argv[ssh_argc++] = remote_command;
    ssh_argv[ssh_argc] = NULL;
    rc = run_ssh(ssh_argv);
    free(ssh_argv);
    return rc;
 }
--- a/tests/test_exec_mode.sh
+++ b/tests/test_exec_mode.sh
@ -26,6 +26,7 @@ if [ ! -f "$BIN" ]; then
 fi
 SSH_OPTS="-n -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o BatchMode=yes -p $PORT"
 TNTCTL_OPTS="--host-key-checking no --known-hosts /dev/null"
 echo "=== TNT Exec Mode Tests ==="
@ -51,14 +52,16 @@ else
    FAIL=$((FAIL + 1))
 fi
-HEALTH_USAGE=$(ssh $SSH_OPTS localhost health extra 2>/dev/null || true)
+HEALTH_USAGE=$(ssh $SSH_OPTS localhost health extra 2>/dev/null)
 HEALTH_USAGE_STATUS=$?
 printf '%s\n' "$HEALTH_USAGE" | grep -q '^health: 用法: health$'
-if [ $? -eq 0 ]; then
+if [ $? -eq 0 ] && [ "$HEALTH_USAGE_STATUS" -eq 64 ]; then
-    echo "✓ no-arg exec usage follows TNT_LANG"
+    echo "✓ no-arg exec usage follows TNT_LANG and exits 64"
    PASS=$((PASS + 1))
 else
    echo "✗ no-arg exec usage output unexpected"
    printf '%s\n' "$HEALTH_USAGE"
    echo "exit status: $HEALTH_USAGE_STATUS"
    FAIL=$((FAIL + 1))
 fi
@ -98,36 +101,42 @@ else
    FAIL=$((FAIL + 1))
 fi
-UNKNOWN_OUTPUT=$(ssh $SSH_OPTS localhost nope 2>/dev/null || true)
+UNKNOWN_OUTPUT=$(ssh $SSH_OPTS localhost nope 2>/dev/null)
 UNKNOWN_STATUS=$?
 printf '%s\n' "$UNKNOWN_OUTPUT" | grep -q '^未知命令: nope$'
-if [ $? -eq 0 ]; then
+if [ $? -eq 0 ] && [ "$UNKNOWN_STATUS" -eq 64 ]; then
-    echo "✓ unknown command follows TNT_LANG"
+    echo "✓ unknown command follows TNT_LANG and exits 64"
    PASS=$((PASS + 1))
 else
    echo "✗ unknown command output unexpected"
    printf '%s\n' "$UNKNOWN_OUTPUT"
    echo "exit status: $UNKNOWN_STATUS"
    FAIL=$((FAIL + 1))
 fi
-POST_USAGE=$(ssh $SSH_OPTS localhost post 2>/dev/null || true)
+POST_USAGE=$(ssh $SSH_OPTS localhost post 2>/dev/null)
 POST_USAGE_STATUS=$?
 printf '%s\n' "$POST_USAGE" | grep -q '^post: 用法: post MESSAGE$'
-if [ $? -eq 0 ]; then
+if [ $? -eq 0 ] && [ "$POST_USAGE_STATUS" -eq 64 ]; then
-    echo "✓ post usage follows TNT_LANG"
+    echo "✓ post usage follows TNT_LANG and exits 64"
    PASS=$((PASS + 1))
 else
    echo "✗ post usage output unexpected"
    printf '%s\n' "$POST_USAGE"
    echo "exit status: $POST_USAGE_STATUS"
    FAIL=$((FAIL + 1))
 fi
-USERS_USAGE=$(ssh $SSH_OPTS localhost users --xml 2>/dev/null || true)
+USERS_USAGE=$(ssh $SSH_OPTS localhost users --xml 2>/dev/null)
 USERS_USAGE_STATUS=$?
 printf '%s\n' "$USERS_USAGE" | grep -q '^users: 用法: users \[--json\]$'
-if [ $? -eq 0 ]; then
+if [ $? -eq 0 ] && [ "$USERS_USAGE_STATUS" -eq 64 ]; then
-    echo "✓ users usage follows TNT_LANG"
+    echo "✓ users usage follows TNT_LANG and exits 64"
    PASS=$((PASS + 1))
 else
    echo "✗ users usage output unexpected"
    printf '%s\n' "$USERS_USAGE"
    echo "exit status: $USERS_USAGE_STATUS"
    FAIL=$((FAIL + 1))
 fi
@ -152,6 +161,106 @@ else
    FAIL=$((FAIL + 1))
 fi
 PERSIST_FAIL_MARKER="persist-fail-marker"
 rm -f "$STATE_DIR/messages.log"
 mkdir "$STATE_DIR/messages.log"
 PERSIST_FAIL_OUTPUT=$(ssh $SSH_OPTS execposter@localhost post "$PERSIST_FAIL_MARKER" 2>/dev/null)
 PERSIST_FAIL_STATUS=$?
 rmdir "$STATE_DIR/messages.log"
 printf '%s\n' "$PERSIST_FAIL_OUTPUT" | grep -q 'posted'
 PERSIST_FAIL_POSTED=$?
 PERSIST_FAIL_TAIL=$(ssh $SSH_OPTS localhost "tail -n 5" 2>/dev/null || true)
 printf '%s\n' "$PERSIST_FAIL_TAIL" | grep -q "$PERSIST_FAIL_MARKER"
 PERSIST_FAIL_VISIBLE=$?
 if [ "$PERSIST_FAIL_STATUS" -eq 1 ] &&
   [ "$PERSIST_FAIL_POSTED" -ne 0 ] &&
   [ "$PERSIST_FAIL_VISIBLE" -ne 0 ]; then
    echo "✓ post persistence failure is not broadcast or acknowledged"
    PASS=$((PASS + 1))
 else
    echo "✗ post persistence failure handling unexpected"
    printf '%s\n' "$PERSIST_FAIL_OUTPUT"
    printf '%s\n' "$PERSIST_FAIL_TAIL"
    echo "exit status: $PERSIST_FAIL_STATUS"
    FAIL=$((FAIL + 1))
 fi
 LONG_MARKER="too-long-exec-marker"
 LONG_COMMAND=$(printf 'post %s %01020d' "$LONG_MARKER" 0)
 LONG_OUTPUT=$(ssh $SSH_OPTS localhost "$LONG_COMMAND" 2>/dev/null)
 LONG_STATUS=$?
 printf '%s\n' "$LONG_OUTPUT" | grep -q '命令过长'
 LONG_ERROR=$?
 LONG_TAIL=$(ssh $SSH_OPTS localhost "tail -n 5" 2>/dev/null || true)
 printf '%s\n' "$LONG_TAIL" | grep -q "$LONG_MARKER"
 LONG_VISIBLE=$?
 if [ "$LONG_STATUS" -eq 64 ] &&
   [ "$LONG_ERROR" -eq 0 ] &&
   [ "$LONG_VISIBLE" -ne 0 ]; then
    echo "✓ overlong exec command is rejected without truncation"
    PASS=$((PASS + 1))
 else
    echo "✗ overlong exec command handling unexpected"
    printf '%s\n' "$LONG_OUTPUT"
    printf '%s\n' "$LONG_TAIL"
    echo "exit status: $LONG_STATUS"
    FAIL=$((FAIL + 1))
 fi
 TNTCTL_HEALTH=$("../tntctl" -p "$PORT" $TNTCTL_OPTS localhost health 2>/dev/null || true)
 if [ "$TNTCTL_HEALTH" = "ok" ]; then
    echo "✓ tntctl health uses exec interface"
    PASS=$((PASS + 1))
 else
    echo "✗ tntctl health failed: $TNTCTL_HEALTH"
    FAIL=$((FAIL + 1))
 fi
 TNTCTL_STATS=$("../tntctl" -p "$PORT" $TNTCTL_OPTS localhost stats --json 2>/dev/null || true)
 printf '%s\n' "$TNTCTL_STATS" | grep -q '"status":"ok"'
 if [ $? -eq 0 ]; then
    echo "✓ tntctl stats --json returns JSON"
    PASS=$((PASS + 1))
 else
    echo "✗ tntctl stats --json output unexpected"
    printf '%s\n' "$TNTCTL_STATS"
    FAIL=$((FAIL + 1))
 fi
 TNTCTL_USERS_USAGE=$("../tntctl" -p "$PORT" $TNTCTL_OPTS localhost users --xml 2>/dev/null)
 TNTCTL_USERS_STATUS=$?
 printf '%s\n' "$TNTCTL_USERS_USAGE" | grep -q '^users: 用法: users \[--json\]$'
 if [ $? -eq 0 ] && [ "$TNTCTL_USERS_STATUS" -eq 64 ]; then
    echo "✓ tntctl preserves remote usage exit 64"
    PASS=$((PASS + 1))
 else
    echo "✗ tntctl users usage output unexpected"
    printf '%s\n' "$TNTCTL_USERS_USAGE"
    echo "exit status: $TNTCTL_USERS_STATUS"
    FAIL=$((FAIL + 1))
 fi
 TNTCTL_POST=$("../tntctl" -p "$PORT" $TNTCTL_OPTS -l ctlposter localhost post "hello from tntctl" 2>/dev/null || true)
 if [ "$TNTCTL_POST" = "posted" ]; then
    echo "✓ tntctl post publishes a message"
    PASS=$((PASS + 1))
 else
    echo "✗ tntctl post failed: $TNTCTL_POST"
    FAIL=$((FAIL + 1))
 fi
 TNTCTL_TAIL=$("../tntctl" -p "$PORT" $TNTCTL_OPTS localhost "tail" "-n" "1" 2>/dev/null || true)
 printf '%s\n' "$TNTCTL_TAIL" | grep -q 'ctlposter' &&
 printf '%s\n' "$TNTCTL_TAIL" | grep -q 'hello from tntctl'
 if [ $? -eq 0 ]; then
    echo "✓ tntctl tail returns recent messages"
    PASS=$((PASS + 1))
 else
    echo "✗ tntctl tail output unexpected"
    printf '%s\n' "$TNTCTL_TAIL"
    FAIL=$((FAIL + 1))
 fi
 EXPECT_SCRIPT="${STATE_DIR}/watcher.expect"
 WATCHER_READY="${STATE_DIR}/watcher.ready"
 cat >"$EXPECT_SCRIPT" <<EOF
@ -160,7 +269,7 @@ spawn ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -p $PORT w
 expect "请输入用户名"
 send "watcher\r"
 exec touch "$WATCHER_READY"
-sleep 8
+sleep 12
 send "\003"
 expect eof
 EOF
@ -213,6 +322,45 @@ else
    FAIL=$((FAIL + 1))
 fi
 MENTION_OUTPUT=$(ssh $SSH_OPTS execposter@localhost post "@watcher hello from exec mention" 2>/dev/null || true)
 if [ "$MENTION_OUTPUT" = "posted" ]; then
    echo "✓ post returns while notifying an interactive mention target"
    PASS=$((PASS + 1))
 else
    echo "✗ mention post failed: $MENTION_OUTPUT"
    FAIL=$((FAIL + 1))
 fi
 MSG_SCRIPT="${STATE_DIR}/private-message.expect"
 cat >"$MSG_SCRIPT" <<EOF
 set timeout 10
 spawn ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -p $PORT sender@localhost
 expect "请输入用户名"
 send "sender\r"
 expect ":help"
 send "\033"
 expect "NORMAL"
 send ":"
 expect ":"
 send "msg watcher hello from private message\r"
 expect "私信已发送给 watcher"
 expect "q:关闭"
 send "q"
 sleep 0.2
 send "\003"
 expect eof
 EOF
 if expect "$MSG_SCRIPT" >"${STATE_DIR}/private-message.log" 2>&1; then
    echo "✓ :msg returns while queuing recipient notification"
    PASS=$((PASS + 1))
 else
    echo "✗ :msg notification path failed"
    sed -n '1,120p' "${STATE_DIR}/private-message.log"
    sed -n '1,120p' "${STATE_DIR}/server.log"
    FAIL=$((FAIL + 1))
 fi
 wait "${INTERACTIVE_PID}" 2>/dev/null || true
 INTERACTIVE_PID=""
--- a/tests/test_tntctl_cli.sh
+++ b/tests/test_tntctl_cli.sh
@ -0,0 +1,133 @@
 #!/bin/sh
 # Local CLI-shape tests for tntctl. Uses a fake ssh in PATH.
 set -u
 PASS=0
 FAIL=0
 BIN="../tntctl"
 STATE_DIR=$(mktemp -d "${TMPDIR:-/tmp}/tntctl-cli-test.XXXXXX")
 FAKE_BIN="${STATE_DIR}/bin"
 SSH_LOG="${STATE_DIR}/ssh.argv"
 cleanup() {
    rm -rf "$STATE_DIR"
 }
 trap cleanup EXIT
 mkdir -p "$FAKE_BIN"
 cat >"$FAKE_BIN/ssh" <<'FAKESSH'
 #!/bin/sh
 printf '%s\n' "$#" > "$TNTCTL_SSH_LOG"
 for arg in "$@"; do
    printf '%s\n' "$arg" >> "$TNTCTL_SSH_LOG"
 done
 case "$*" in
    *" users --xml") exit 64 ;;
    *) printf 'fake-ok\n'; exit 0 ;;
 esac
 FAKESSH
 chmod +x "$FAKE_BIN/ssh"
 run_ok() {
    label=$1
    shift
    : > "$SSH_LOG"
    PATH="$FAKE_BIN:$PATH" TNTCTL_SSH_LOG="$SSH_LOG" "$@" >/dev/null 2>&1
    status=$?
    if [ "$status" -eq 0 ]; then
        echo "✓ $label"
        PASS=$((PASS + 1))
    else
        echo "✗ $label (exit $status)"
        FAIL=$((FAIL + 1))
    fi
 }
 run_usage() {
    label=$1
    shift
    rm -f "$SSH_LOG"
    PATH="$FAKE_BIN:$PATH" TNTCTL_SSH_LOG="$SSH_LOG" "$@" >/dev/null 2>&1
    status=$?
    if [ "$status" -eq 64 ] && [ ! -f "$SSH_LOG" ]; then
        echo "✓ $label"
        PASS=$((PASS + 1))
    else
        echo "✗ $label (exit $status)"
        [ -f "$SSH_LOG" ] && echo "fake ssh was invoked"
        FAIL=$((FAIL + 1))
    fi
 }
 echo "=== TNTCTL CLI Tests ==="
 if [ ! -x "$BIN" ]; then
    echo "Error: Binary $BIN not found. Run make first."
    exit 1
 fi
 VERSION_OUTPUT=$("$BIN" --version 2>/dev/null || true)
 case "$VERSION_OUTPUT" in
    "tntctl "*) echo "✓ version prints"; PASS=$((PASS + 1)) ;;
    *) echo "✗ version output unexpected: $VERSION_OUTPUT"; FAIL=$((FAIL + 1)) ;;
 esac
 run_ok "basic argv shape" "$BIN" -p 2222 example.com health
 grep -q '^example.com$' "$SSH_LOG" &&
 grep -q '^health$' "$SSH_LOG"
 if [ $? -eq 0 ]; then
    echo "✓ fake ssh receives host and command as separate argv"
    PASS=$((PASS + 1))
 else
    echo "✗ fake ssh argv unexpected"
    cat "$SSH_LOG"
    FAIL=$((FAIL + 1))
 fi
 run_ok "bounded host-key options are passed safely" "$BIN" --host-key-checking accept-new --known-hosts "$STATE_DIR/known_hosts" example.com health
 grep -q '^StrictHostKeyChecking=accept-new$' "$SSH_LOG" &&
 grep -q "^UserKnownHostsFile=$STATE_DIR/known_hosts$" "$SSH_LOG"
 if [ $? -eq 0 ]; then
    echo "✓ bounded host-key options are explicit"
    PASS=$((PASS + 1))
 else
    echo "✗ bounded host-key options missing"
    cat "$SSH_LOG"
    FAIL=$((FAIL + 1))
 fi
 run_ok "login builds user@host destination" "$BIN" -l operator example.com post "hello"
 grep -q '^operator@example.com$' "$SSH_LOG"
 if [ $? -eq 0 ]; then
    echo "✓ login destination is explicit"
    PASS=$((PASS + 1))
 else
    echo "✗ login destination unexpected"
    cat "$SSH_LOG"
    FAIL=$((FAIL + 1))
 fi
 PATH="$FAKE_BIN:$PATH" TNTCTL_SSH_LOG="$SSH_LOG" "$BIN" example.com users --xml >/dev/null 2>&1
 REMOTE_STATUS=$?
 if [ "$REMOTE_STATUS" -eq 64 ]; then
    echo "✓ remote usage status is preserved"
    PASS=$((PASS + 1))
 else
    echo "✗ remote usage status unexpected: $REMOTE_STATUS"
    FAIL=$((FAIL + 1))
 fi
 run_usage "rejects login starting with dash" "$BIN" -l -V example.com health
 run_usage "rejects host starting with dash" "$BIN" -bad health
 run_usage "rejects unknown command locally" "$BIN" example.com 'health;id'
 run_usage "rejects newline command arg locally" "$BIN" example.com post "hello
 world"
 run_usage "rejects arbitrary ssh option" "$BIN" --ssh-option ProxyCommand=id example.com health
 run_usage "rejects invalid host-key mode" "$BIN" --host-key-checking maybe example.com health
 echo ""
 echo "PASSED: $PASS"
 echo "FAILED: $FAIL"
 [ "$FAIL" -eq 0 ] && echo "All tests passed" || echo "Some tests failed"
 exit "$FAIL"
--- a/tests/unit/test_chat_room.c
+++ b/tests/unit/test_chat_room.c
@ -159,8 +159,9 @@ TEST(room_remove_nonexistent_client) {
 TEST(room_add_client_full) {
    chat_room_t *room = room_create();
-    client_t clients[MAX_CLIENTS + 1];
+    client_t *clients = calloc((size_t)room->client_capacity + 1,
-    memset(clients, 0, sizeof(clients));
+                               sizeof(*clients));
    assert(clients != NULL);
    for (int i = 0; i < room->client_capacity; i++) {
        assert(room_add_client(room, &clients[i]) == 0);
@ -169,6 +170,23 @@ TEST(room_add_client_full) {
    assert(room_add_client(room, &clients[room->client_capacity]) == -1);
    assert(room_get_client_count(room) == room->client_capacity);
    free(clients);
    room_destroy(room);
 }
 TEST(room_capacity_follows_tnt_max_connections) {
    setenv("TNT_MAX_CONNECTIONS", "3", 1);
    chat_room_t *room = room_create();
    unsetenv("TNT_MAX_CONNECTIONS");
    client_t clients[4];
    memset(clients, 0, sizeof(clients));
    assert(room->client_capacity == 3);
    assert(room_add_client(room, &clients[0]) == 0);
    assert(room_add_client(room, &clients[1]) == 0);
    assert(room_add_client(room, &clients[2]) == 0);
    assert(room_add_client(room, &clients[3]) == -1);
    room_destroy(room);
 }
@ -201,6 +219,7 @@ int main(void) {
    RUN_TEST(room_client_count);
    RUN_TEST(room_remove_nonexistent_client);
    RUN_TEST(room_add_client_full);
    RUN_TEST(room_capacity_follows_tnt_max_connections);
    RUN_TEST(room_message_count_threadsafe);
    printf("\nAll %d tests passed!\n", tests_passed);
--- a/tests/unit/test_i18n.c
+++ b/tests/unit/test_i18n.c
@ -147,6 +147,10 @@ TEST(text_lookup_matches_language) {
                  "message cannot be empty") != NULL);
    assert(strstr(i18n_text(UI_LANG_ZH, I18N_EXEC_POST_EMPTY),
                  "消息不能为空") != NULL);
    assert(strstr(i18n_text(UI_LANG_EN, I18N_EXEC_COMMAND_TOO_LONG),
                  "command too long") != NULL);
    assert(strstr(i18n_text(UI_LANG_ZH, I18N_EXEC_COMMAND_TOO_LONG),
                  "命令过长") != NULL);
    assert(strstr(i18n_text(UI_LANG_EN, I18N_EXEC_UNKNOWN_COMMAND_FORMAT),
                  "Unknown command") != NULL);
    assert(strstr(i18n_text(UI_LANG_ZH, I18N_EXEC_UNKNOWN_COMMAND_FORMAT),
--- a/tnt.1
+++ b/tnt.1
@ -144,6 +144,30 @@ ssh host \-p 2222 health
 Exit codes follow
 .BR sysexits (3)
 conventions.
 .SH EXIT STATUS
 .TP
 .B 0
 Success.
 .TP
 .B 1
 Runtime error, such as I/O failure, allocation failure, or persistence failure.
 .TP
 .B 64
 Usage error, such as an unknown command, invalid option, or invalid argument
 shape.
 .TP
 .B 69
 Reserved for the local
 .BR tntctl (1)
 wrapper when SSH transport is unavailable.
 .TP
 .B 78
 Reserved for future local
 .BR tntctl (1)
 configuration errors.
 .PP
 The SSH exec JSON field contract is documented in
 .IR docs/INTERFACE.md .
 .SH ENVIRONMENT
 .TP
 .B PORT
--- a/tntctl.1
+++ b/tntctl.1
@ -0,0 +1,119 @@
 .\" tntctl(1) - TNT control client
 .TH TNTCTL 1 "2026-05-24" "TNT 1.0.1" "User Commands"
 .SH NAME
 tntctl \- thin control client for a TNT server
 .SH SYNOPSIS
 .B tntctl
 .RB [ \-p | \-\-port
 .IR port ]
 .RB [ \-l | \-\-login
 .IR user ]
 .RB [ \-\-host\-key\-checking
 .IR mode ]
 .RB [ \-\-known\-hosts
 .IR file ]
 .I host
 .I command
 .RI [ args ...]
 .SH DESCRIPTION
 .B tntctl
 runs TNT's documented SSH exec commands through the local
 .BR ssh (1)
 client.
 It is intentionally a thin wrapper: it does not introduce a second control
 protocol and does not bypass SSH host-key checking or authentication.
 .PP
 The command names, exit statuses, and JSON fields are shared with the SSH exec
 interface documented in
 .IR docs/INTERFACE.md .
 .SH OPTIONS
 .TP
 .BR \-p ", " \-\-port " " \fIport\fR
 Connect to
 .I port
 instead of the default 2222.
 .TP
 .BR \-l ", " \-\-login " " \fIuser\fR
 Use
 .I user
 as the SSH login name.
 For
 .B post
 commands, TNT uses this login name as the exec message identity.
 .TP
 .BR \-\-host\-key\-checking " " \fIyes|accept-new|no\fR
 Set OpenSSH
 .B StrictHostKeyChecking
 to one of the listed modes.
 .TP
 .BR \-\-known\-hosts " " \fIfile\fR
 Set the OpenSSH
 .B UserKnownHostsFile
 path.
 .TP
 .BR \-V ", " \-\-version
 Print version and exit.
 .TP
 .BR \-h ", " \-\-help
 Print a short usage summary and exit.
 .SH COMMANDS
 .TP
 .B health
 Print service health.
 .TP
 .B stats [--json]
 Print room statistics.
 .TP
 .B users [--json]
 List online users.
 .TP
 .B tail [N]
 Print recent messages.
 .TP
 .B tail -n N
 Print recent messages.
 .TP
 .B post MESSAGE
 Post a message non-interactively.
 .TP
 .B help
 Print the server exec help.
 .SH EXAMPLES
 .nf
 tntctl chat.example.com health
 tntctl -p 2222 chat.example.com stats --json
 tntctl -l operator chat.example.com post "service notice"
 tntctl --host-key-checking accept-new chat.example.com users
 .fi
 .SH EXIT STATUS
 .TP
 .B 0
 Success.
 .TP
 .B 1
 Runtime error in the local wrapper.
 .TP
 .B 64
 Usage error, either from
 .B tntctl
 or the remote TNT exec command.
 .TP
 .B 69
 The local
 .BR ssh (1)
 client could not be executed or exited with OpenSSH's transport-failure status.
 .TP
 .B 78
 Reserved for future local configuration errors.
 .SH SECURITY
 .B tntctl
 passes arguments directly to
 .BR ssh (1)
 without invoking a local shell.
 It does not accept arbitrary SSH options or a password option.
 Only the bounded host-key options above are exposed.  Use normal SSH
 configuration for jump hosts, identity files, and authentication.  If the server
 requires an access token, enter it through the normal SSH password prompt.
 .SH SEE ALSO
 .BR tnt (1),
 .BR ssh (1)