docs(quick-260504-bw4): Add SSH support to claudebox

This commit is contained in:
Christopher Mühl 2026-05-04 08:41:52 +00:00
parent b2aeb2fd12
commit 9651ce759d
3 changed files with 360 additions and 1 deletions

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@ -28,7 +28,7 @@ See: .planning/PROJECT.md (updated 2026-04-09)
Phase: 04 of 3 (sandbox aware prompting) Phase: 04 of 3 (sandbox aware prompting)
Plan: Not started Plan: Not started
Status: Ready to execute Status: Ready to execute
Last activity: 2026-04-10 Last activity: 2026-05-04 - Completed quick task 260504-bw4: Add SSH support to claudebox
Progress: [███░░░░░░░] 33% Progress: [███░░░░░░░] 33%
@ -63,6 +63,7 @@ None.
| # | Description | Date | Commit | Directory | | # | Description | Date | Commit | Directory |
|---|-------------|------|--------|-----------| |---|-------------|------|--------|-----------|
| 260410-d4u | on non-nixos hosts, bwrap fails because /etc/static does not exist | 2026-04-10 | 97c10f8 | [260410-d4u-on-non-nixos-hosts-bwrap-fails-because-e](./quick/260410-d4u-on-non-nixos-hosts-bwrap-fails-because-e/) | | 260410-d4u | on non-nixos hosts, bwrap fails because /etc/static does not exist | 2026-04-10 | 97c10f8 | [260410-d4u-on-non-nixos-hosts-bwrap-fails-because-e](./quick/260410-d4u-on-non-nixos-hosts-bwrap-fails-because-e/) |
| 260504-bw4 | Add SSH support to claudebox: --with-ssh flag forwards SSH_AUTH_SOCK agent socket, --ssh-key flag mounts specific key files read-only into sandbox ~/.ssh/ | 2026-05-04 | b2aeb2f | [260504-bw4-add-ssh-support-to-claudebox-with-ssh-fl](./quick/260504-bw4-add-ssh-support-to-claudebox-with-ssh-fl/) |
## Session Continuity ## Session Continuity

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@ -0,0 +1,290 @@
---
phase: 260504-bw4
plan: 01
type: execute
wave: 1
depends_on: []
files_modified:
- claudebox.sh
- README.md
autonomous: true
requirements:
- SSH-01
- SSH-02
- SSH-03
- SSH-04
must_haves:
truths:
- "Running `claudebox --with-ssh` forwards $SSH_AUTH_SOCK into the sandbox at the same path with SSH_AUTH_SOCK env var set"
- "Running `claudebox --ssh-key ~/.ssh/id_ed25519` mounts that file (and its .pub if present) read-only into the sandbox at ~/.ssh/id_ed25519"
- "When any SSH mechanism is active, ~/.ssh/known_hosts is mounted read-only (if it exists on the host)"
- "--ssh-key is repeatable; multiple keys all land in the synthetic sandbox ~/.ssh/"
- "--with-ssh and --ssh-key can be combined in one invocation"
- "The audit display shows active SSH mechanism(s) and mounts"
- "The --dry-run output includes the SSH bwrap flags"
- "SANDBOX.md inside the sandbox reflects that SSH is available when SSH flags are active"
- "README.md documents SSH usage including ssh-agent setup for bash and fish"
artifacts:
- path: "claudebox.sh"
provides: "--with-ssh and --ssh-key flags, SSH bwrap mounts, conditional SANDBOX.md, audit/dry-run integration"
contains: "--with-ssh"
- path: "README.md"
provides: "SSH section + Flags table entries"
contains: "## SSH"
key_links:
- from: "claudebox.sh flag parser"
to: "BWRAP_ARGS SSH mount block"
via: "WITH_SSH and SSH_KEYS array set during arg parsing, consumed when assembling bwrap args"
pattern: "WITH_SSH|SSH_KEYS"
- from: "claudebox.sh SSH state"
to: "SANDBOX.md heredoc generation"
via: "conditional Default Restrictions text based on WITH_SSH/SSH_KEYS"
pattern: "SANDBOX.md"
- from: "claudebox.sh SSH state"
to: "print_audit + dry-run output"
via: "Mounts section emits SSH lines when active"
pattern: "print_audit|DRY_RUN"
---
<objective>
Add two opt-in SSH mechanisms to claudebox so users can `git push/pull` from inside the sandbox without exposing SSH keys by default.
Purpose: Today the sandbox blocks all SSH. Real workflows need it for git remotes. The right answer is opt-in agent forwarding (`--with-ssh`) plus explicit key file mounting (`--ssh-key`), with audit visibility so the user always sees what crossed the boundary.
Output: Updated `claudebox.sh` implementing both flags, audit + dry-run + SANDBOX.md integration, and an updated `README.md` documenting setup and usage.
</objective>
<context>
@./CLAUDE.md
@./claudebox.sh
@./README.md
@.planning/STATE.md
<interfaces>
<!-- Existing claudebox.sh structures the new code must integrate with -->
Flag parsing pattern (lines 9-20):
```bash
while (( $# > 0 )); do
case "$1" in
--yes|-y) SKIP_AUDIT=true ;;
...
*) CLAUDE_ARGS+=("$1") ;;
esac
shift
done
```
Audit data structure (lines 240-245): AUDIT_SANDBOX_KEYS / AUDIT_HOST_KEYS / AUDIT_EXTRA_KEYS arrays + parallel _VALS assoc arrays. SSH mounts are mounts, not env vars — they belong in the print_audit `Mounts:` section (line 361), not in the env arrays. SSH_AUTH_SOCK is an env var — it should go through ENV_ARGS via the AUDIT_HOST_KEYS path.
SANDBOX.md generation (lines 185-222): single heredoc with `'SANDBOXEOF'` (literal). To make it conditional we either (a) split it into pieces, or (b) generate it without a quoted heredoc and use bash conditionals. Approach: keep the static parts as a heredoc, then append a conditional "SSH" subsection before writing the "Git" section, OR rewrite as `cat <<SANDBOXEOF` (unquoted) with a `${SSH_RESTRICTIONS_NOTE}` placeholder. Prefer the placeholder approach for readability.
Dry-run output (lines 405-451): mirrors BWRAP_ARGS construction. Any new bwrap flags added to BWRAP_ARGS must also be emitted in the dry-run echo block.
BWRAP_ARGS construction (lines 453-494): conditional mounts (CLAUDE_JSON_MOUNT, CREDS_MOUNT) are appended after the base array. SSH mounts follow the same pattern.
</interfaces>
</context>
<tasks>
<task type="auto" tdd="false">
<name>Task 1: Implement --with-ssh and --ssh-key flag parsing + bwrap mounts</name>
<files>claudebox.sh</files>
<behavior>
- `--with-ssh` sets WITH_SSH=true. If $SSH_AUTH_SOCK is set and is a socket on the host, add `--bind $SSH_AUTH_SOCK $SSH_AUTH_SOCK` to BWRAP_ARGS and `--setenv SSH_AUTH_SOCK $SSH_AUTH_SOCK` to ENV_ARGS. If the var is unset or the path is not a socket, print a warning to stderr and continue without forwarding.
- `--ssh-key <path>` is repeatable. Each value is appended to a SSH_KEYS array. Path is expanded (`~` -> $HOME) and validated: file must exist and be readable; otherwise exit 1 with an error.
- When WITH_SSH=true OR SSH_KEYS is non-empty: add `--dir $HOME/.ssh` to BWRAP_ARGS so the sandbox has a real ~/.ssh directory inside the home tmpfs.
- For each key in SSH_KEYS: add `--ro-bind <abs-path> $HOME/.ssh/<basename>`. If `<abs-path>.pub` exists on the host, also `--ro-bind <abs-path>.pub $HOME/.ssh/<basename>.pub`.
- When SSH is active AND `~/.ssh/known_hosts` exists on the host: add `--ro-bind $HOME/.ssh/known_hosts $HOME/.ssh/known_hosts` exactly once (shared between both mechanisms).
- The dry-run block (lines 405-451) emits the same SSH lines so `claudebox --dry-run --with-ssh --ssh-key ~/.ssh/id_ed25519` prints them.
</behavior>
<action>
1. In the flag-parsing `case` block (around line 10), add:
```bash
--with-ssh) WITH_SSH=true ;;
--ssh-key)
shift
[[ $# -gt 0 ]] || { echo "Error: --ssh-key requires a path" >&2; exit 1; }
SSH_KEYS+=("${1/#\~/$HOME}")
;;
```
Initialize `WITH_SSH=false` and `SSH_KEYS=()` near the top with the other flag defaults.
2. After argument parsing, add a validation+resolution block that:
- For each path in SSH_KEYS: resolve to absolute, verify exists+readable, replace array entry with absolute path, error+exit if missing.
- If WITH_SSH=true: check `[[ -v SSH_AUTH_SOCK && -S "$SSH_AUTH_SOCK" ]]`. If not, print `${YELLOW}Warning: --with-ssh given but SSH_AUTH_SOCK is unset or not a socket; agent will not be forwarded.${RESET}` and set WITH_SSH=false. (Color vars are defined later — move this block to AFTER the ANSI block at line 107, or use plain text.)
- Compute `SSH_ACTIVE=true` if WITH_SSH=true OR ${#SSH_KEYS[@]} > 0; else false.
- Compute `KNOWN_HOSTS_MOUNT=true` if SSH_ACTIVE && `[[ -f $HOME/.ssh/known_hosts ]]`.
3. Where ENV_ARGS is built (after line 256): if WITH_SSH=true, append `--setenv SSH_AUTH_SOCK $SSH_AUTH_SOCK` and add to AUDIT_HOST_KEYS/VALS so it shows in the audit's `[>]` section.
4. Where BWRAP_ARGS is assembled (lines 453-487), after the existing conditional mounts (CLAUDE_JSON, CREDS) and before the trailing `--ro-bind GITCONFIG_TMP ...` line, insert:
```bash
if [[ "$SSH_ACTIVE" == true ]]; then
BWRAP_ARGS+=(--dir "$HOME/.ssh")
if [[ "$WITH_SSH" == true ]]; then
BWRAP_ARGS+=(--bind "$SSH_AUTH_SOCK" "$SSH_AUTH_SOCK")
fi
for key in "${SSH_KEYS[@]}"; do
base=$(basename "$key")
BWRAP_ARGS+=(--ro-bind "$key" "$HOME/.ssh/$base")
if [[ -f "${key}.pub" ]]; then
BWRAP_ARGS+=(--ro-bind "${key}.pub" "$HOME/.ssh/$base.pub")
fi
done
if [[ "$KNOWN_HOSTS_MOUNT" == true ]]; then
BWRAP_ARGS+=(--ro-bind "$HOME/.ssh/known_hosts" "$HOME/.ssh/known_hosts")
fi
fi
```
5. Mirror all of (4) in the dry-run echo block (after the CREDS_MOUNT block around line 444, before the GITCONFIG line at 445), printing the same flags as quoted strings.
6. Update the audit display (`print_audit`, around line 361) to emit additional Mounts lines when SSH_ACTIVE:
- `agent <socket-path> (read-write, --with-ssh)` if WITH_SSH
- For each key: `ssh-key <path> (read-only)`; add ` + .pub` line if pub exists
- `known_hosts <path> (read-only)` if KNOWN_HOSTS_MOUNT
</action>
<verify>
<automated>bash -n claudebox.sh && claudebox --dry-run --with-ssh 2>&1 | grep -q "SSH_AUTH_SOCK\|Warning: --with-ssh" && echo "Note: full agent forwarding only verifiable when ssh-agent is running on host"</automated>
</verify>
<done>
- `claudebox --dry-run --with-ssh` (with agent running) prints `--bind $SSH_AUTH_SOCK ...` and `--setenv SSH_AUTH_SOCK ...`.
- `claudebox --dry-run --ssh-key ~/.ssh/id_ed25519` prints `--dir $HOME/.ssh`, `--ro-bind <key> $HOME/.ssh/id_ed25519`, and (if present) the matching .pub bind.
- Both flags together print all of the above plus a single `--ro-bind .../known_hosts ...` line (if known_hosts exists).
- Missing key file → `claudebox --ssh-key /nonexistent` exits 1 with a clear error.
- Audit display shows the SSH mounts in the `Mounts:` section.
- `bash -n claudebox.sh` passes; shellcheck (run by writeShellApplication at build time) passes.
</done>
</task>
<task type="auto" tdd="false">
<name>Task 2: Make SANDBOX.md conditional on SSH activation</name>
<files>claudebox.sh</files>
<behavior>
- When SSH_ACTIVE=false: SANDBOX.md keeps the current "Default Restrictions" section listing SSH keys as not mounted, and the Git section recommends HTTPS.
- When SSH_ACTIVE=true: "Default Restrictions" no longer lists SSH keys; a new "SSH" subsection states which mechanism is active (agent forwarding via $SSH_AUTH_SOCK and/or explicit key files at ~/.ssh/), and the Git section drops the HTTPS-preference sentence (or replaces it with: "SSH remotes work in this session.").
</behavior>
<action>
1. Replace the quoted heredoc at lines 185-222 with an unquoted heredoc using shell-side composed variables. Build them before the heredoc:
```bash
if [[ "$SSH_ACTIVE" == true ]]; then
_SSH_NOTES=""
[[ "$WITH_SSH" == true ]] && _SSH_NOTES+="- ssh-agent socket forwarded via \$SSH_AUTH_SOCK\n"
(( ${#SSH_KEYS[@]} > 0 )) && _SSH_NOTES+="- Explicit key file(s) mounted read-only at ~/.ssh/\n"
SANDBOX_RESTRICTIONS_BLOCK=$'## Default Restrictions\n\nBy default, the following are not mounted into the sandbox:\n- GPG and age keys (~/.gnupg, age key files)\n- Cloud credentials (~/.aws, ~/.config/gcloud)\n- Tailscale state\n\n## SSH\n\nSSH is available in this session:\n'"$(printf "$_SSH_NOTES")"$'\nUse `git push`/`git pull` over SSH normally.'
SANDBOX_GIT_TAIL="SSH remotes work in this session."
else
SANDBOX_RESTRICTIONS_BLOCK=$'## Default Restrictions\n\nBy default, the following are not mounted into the sandbox:\n- SSH keys (~/.ssh)\n- GPG and age keys (~/.gnupg, age key files)\n- Cloud credentials (~/.aws, ~/.config/gcloud)\n- Tailscale state\n\nIf your setup has been customized, some of these may be available.'
SANDBOX_GIT_TAIL="For remote operations, prefer HTTPS URLs over SSH since SSH keys are not available by default."
fi
```
2. Rewrite the heredoc as `cat > "$HOME/.claudebox/SANDBOX.md" <<SANDBOXEOF` (unquoted) and substitute `${SANDBOX_RESTRICTIONS_BLOCK}` and `${SANDBOX_GIT_TAIL}` in place of the static text. Keep the "Installing Tools" section static.
3. Verify the resulting SANDBOX.md renders sensibly in both modes.
</action>
<verify>
<automated>bash -n claudebox.sh && claudebox --dry-run -y >/dev/null 2>&1 && grep -q "SSH keys (~/.ssh)" "$HOME/.claudebox/SANDBOX.md" && echo "no-ssh path OK" && claudebox --dry-run -y --ssh-key /etc/hostname >/dev/null 2>&1 && grep -q "## SSH" "$HOME/.claudebox/SANDBOX.md" && ! grep -q "SSH keys (~/.ssh)" "$HOME/.claudebox/SANDBOX.md" && echo "ssh-active path OK"</automated>
</verify>
<done>
- Without SSH flags: SANDBOX.md contains "SSH keys (~/.ssh)" in restrictions and HTTPS preference in Git section.
- With `--with-ssh` or `--ssh-key`: SANDBOX.md drops the SSH-keys restriction line, gains a "## SSH" section listing active mechanisms, and Git section says SSH works.
- `bash -n` and shellcheck pass.
</done>
</task>
<task type="auto" tdd="false">
<name>Task 3: Document SSH support in README.md</name>
<files>README.md</files>
<behavior>
- Flags table includes `--with-ssh` and `--ssh-key <path>` rows with concise descriptions.
- New `## SSH` section after `## Env vars` (and before `## How it works`) covers: when you need SSH (git push/pull over SSH remotes), the agent-forwarding flow with bash and fish setup commands, the agent-dies-with-shell caveat, the explicit key-file flow, and guidance on when to prefer each.
</behavior>
<action>
1. Update the Flags table (lines 34-41) by inserting two rows after `--shell`:
```
| `--with-ssh` | Forward $SSH_AUTH_SOCK into the sandbox (requires running ssh-agent) |
| `--ssh-key <path>` | Mount a private key file read-only into the sandbox ~/.ssh/ (repeatable) |
```
2. Add a new `## SSH` section between the existing `## Env vars` and `## How it works` sections with this content (verbatim shape, write in the same plain-prose tone as the rest of the README — no marketing fluff):
```markdown
## SSH
SSH is opt-in. By default no keys or agent socket cross the sandbox boundary, which means git push/pull over SSH remotes won't work. Two mechanisms are available — pick whichever matches your workflow.
### `--with-ssh` (agent forwarding)
Forwards `$SSH_AUTH_SOCK` into the sandbox so any keys loaded in your ssh-agent are usable inside. Your private key files are never mounted; only the agent socket is.
Start an agent before launching claudebox. The agent dies with the shell that started it, so don't expect it to survive across terminals.
Bash:
```bash
eval "$(ssh-agent)"
ssh-add ~/.ssh/id_ed25519
claudebox --with-ssh
```
Fish:
```fish
eval (ssh-agent -c)
ssh-add ~/.ssh/id_ed25519
claudebox --with-ssh
```
If `--with-ssh` is passed but no agent is running, claudebox warns and continues without forwarding.
### `--ssh-key <path>` (explicit key files)
Mounts a specific private key (and matching `.pub`, if present) read-only into the sandbox at `~/.ssh/<basename>`. Repeatable — pass it multiple times for multiple keys.
```bash
claudebox --ssh-key ~/.ssh/id_ed25519
claudebox --ssh-key ~/.ssh/id_work --ssh-key ~/.ssh/id_personal
```
Prefer this when you don't have an agent running, or when you want to scope exactly which keys the sandbox can use regardless of what's loaded in the agent.
### known_hosts
When either flag is active, `~/.ssh/known_hosts` is mounted read-only (if it exists) so SSH host verification works without prompting.
Both flags can be combined.
```
</action>
<verify>
<automated>grep -q "^## SSH" README.md && grep -q "\-\-with-ssh" README.md && grep -q "\-\-ssh-key" README.md && grep -q "ssh-agent -c" README.md && grep -q "known_hosts" README.md</automated>
</verify>
<done>
- README.md Flags table lists both new flags.
- README.md has a `## SSH` section with bash + fish agent setup, explicit-key usage, and known_hosts note.
- No broken markdown structure (sections in order, code fences balanced).
</done>
</task>
</tasks>
<verification>
End-to-end smoke checks:
1. `bash -n claudebox.sh` — syntax valid.
2. `nix build` (or `nix flake check`) succeeds — shellcheck via writeShellApplication passes.
3. `claudebox --dry-run` (no SSH flags) — output contains no `--bind $SSH_AUTH_SOCK`, no `~/.ssh` mounts.
4. With agent running: `eval "$(ssh-agent)" && claudebox --dry-run --with-ssh` — output contains `--bind <socket> <socket>` and `--setenv SSH_AUTH_SOCK ...`.
5. `claudebox --dry-run --ssh-key ~/.ssh/id_ed25519` (assuming key exists) — output contains `--dir $HOME/.ssh`, `--ro-bind <key> $HOME/.ssh/id_ed25519`, and `.pub` bind if present.
6. `claudebox --dry-run --ssh-key /nonexistent` — exits non-zero with clear error.
7. SANDBOX.md content matches SSH state (verify by inspecting `~/.claudebox/SANDBOX.md` after a dry run with and without flags).
8. README renders correctly (visual or `, glow README.md`).
</verification>
<success_criteria>
- All three tasks complete and `<done>` criteria met.
- Both flags work in isolation, together, and respect missing-input failure modes.
- Audit display + dry-run + SANDBOX.md all reflect SSH state consistently.
- README documents the feature for both bash and fish users.
- No regressions: running `claudebox` without any SSH flag behaves exactly as before.
</success_criteria>
<output>
After completion, create `.planning/quick/260504-bw4-add-ssh-support-to-claudebox-with-ssh-fl/260504-bw4-SUMMARY.md`.
</output>

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@ -0,0 +1,68 @@
---
phase: 260504-bw4
plan: 01
subsystem: sandbox/ssh
tags: [ssh, bwrap, security, opt-in]
dependency_graph:
requires: []
provides: [ssh-agent-forwarding, ssh-key-mounts, sandbox-ssh-awareness]
affects: [claudebox.sh, README.md]
tech_stack:
added: []
patterns: [opt-in SSH via bwrap --bind/--ro-bind, conditional SANDBOX.md generation]
key_files:
modified:
- claudebox.sh
- README.md
decisions:
- SSH is opt-in: no keys or sockets cross the sandbox boundary without explicit flags
- --with-ssh validation: silently degrades to no-op with warning if ssh-agent is not running
- SANDBOX.md uses unquoted heredoc with pre-composed variables for conditional content
- known_hosts mounted once if either SSH mechanism is active (shared between --with-ssh and --ssh-key)
metrics:
duration: 8min
completed: 2026-05-04
tasks: 3
files: 2
---
# Quick Task 260504-bw4: Add SSH Support to claudebox Summary
One-liner: Opt-in SSH via `--with-ssh` (agent socket forwarding) and `--ssh-key` (explicit key file mounts), with audit/dry-run/SANDBOX.md integration and README documentation.
## Tasks Completed
| Task | Name | Commit | Files |
|------|------|--------|-------|
| 1 | Implement --with-ssh and --ssh-key flag parsing + bwrap mounts | 41ebf10 | claudebox.sh |
| 2 | Make SANDBOX.md conditional on SSH activation | e9154fd | claudebox.sh |
| 3 | Document SSH support in README.md | b2aeb2f | README.md |
## What Was Built
**claudebox.sh** now accepts two new flags:
- `--with-ssh`: validates `$SSH_AUTH_SOCK` is a real socket, adds `--bind $SSH_AUTH_SOCK $SSH_AUTH_SOCK` and `--setenv SSH_AUTH_SOCK` to bwrap args, degrades gracefully with a warning if no agent is running.
- `--ssh-key <path>`: repeatable, validates file exists+readable, mounts key (and `.pub` if present) read-only into `~/.ssh/<basename>` inside the sandbox.
- When either mechanism is active: `--dir ~/.ssh` is added, and `~/.ssh/known_hosts` is mounted read-only if it exists on the host.
- Audit display shows SSH mounts in the Mounts section.
- `--dry-run` output mirrors all SSH bwrap flags.
- SANDBOX.md is now generated conditionally: no-SSH mode lists SSH keys in restrictions and recommends HTTPS; SSH-active mode drops that restriction, adds a `## SSH` section describing which mechanisms are active, and says SSH remotes work.
**README.md** gains two flag table rows and a `## SSH` section covering both mechanisms, bash/fish agent setup, the agent-lifetime caveat, explicit key usage, and the known_hosts note.
## Deviations from Plan
None - plan executed exactly as written.
## Threat Flags
No new threat surface introduced. SSH flags are opt-in and explicitly documented. The agent socket bind is scope-limited to `--bind $SSH_AUTH_SOCK $SSH_AUTH_SOCK` (only the socket path the user explicitly opts into). Key files are read-only.
## Self-Check: PASSED
- claudebox.sh: FOUND
- README.md: FOUND
- 41ebf10 (Task 1): FOUND
- e9154fd (Task 2): FOUND
- b2aeb2f (Task 3): FOUND