Diagnose

diagnose

This skill turns your agent into its own first-line support. Instead of forwarding "something's wrong" messages to a human, the agent inspects the VM, identifies the root cause, and either fixes it or reports a precise diagnosis.

When to trigger

Trigger this skill automatically when:

• The user says anything like "something's wrong", "not working", "broken", "help", "can't connect", "error", or "I'm stuck".
• Any command or tool returns a non-zero exit code and you don't already know why.
• A StopFailure or similar hook fires.
• An agent you spawned goes silent or returns a generic / timeout error class.

Do not trigger the security audit sub-capability automatically — run it only when the user explicitly asks for a security check or audit.

Standard health check

Run these in order. Stop at the first critical failure and attempt a fix before continuing. Report the full picture at the end.

1. Auth state

# Check which agent types are authenticated on this host.
sudo 5dive doctor --json | jq '.data.checks | map(select(.name | startswith("auth")))'

If a type comes back status: "fail", that's why agents of that type can't start. Fix with auth set (API key) or guide the user through auth start (OAuth):

# API key path — pipe the key, never leave it in the shell history.
echo "$KEY" | sudo 5dive agent auth set claude --api-key=- --json

2. Recent 5dive-cli errors

# Last 50 error/warning lines from the CLI audit log.
sudo journalctl -u '5dive-agent@*' -p warning -n 50 --no-pager

Look for repeated auth_required, not_running, or timeout entries — they pin down which agent is failing and why.

3. Service health

# Overall host check — exits 0 even with failures, read data.summary.errors.
sudo 5dive doctor --json

# Per-agent status (running / stopped / failed).
sudo 5dive agent list --json | jq '.data.agents | to_entries[] | {name:.key, status:.value.status}'

# Full systemd state for a specific agent:
sudo systemctl status '5dive-agent@<name>'

A failed unit usually means the agent crashed on startup. Check journalctl -u 5dive-agent@<name> -n 30 --no-pager for the stack trace.

4. Disk usage

# Filesystem usage — warn if any mount is over 80 %.
df -h | awk 'NR==1 || $5+0 > 80'

# Top 10 disk consumers under /home and /var/lib/5dive:
du -sh /home/*/  /var/lib/5dive/ 2>/dev/null | sort -rh | head -10

High disk is the #1 cause of silent install failures and agent crashes. Clean logs with sudo journalctl --vacuum-size=200M if journals are the culprit.

5. Memory

free -h
# Swap usage over 50 % with low free RAM = OOM risk.

If an agent OOM-killed, systemd shows status=1/KILLED and journalctl shows Killed process. The fix is usually sudo 5dive agent rm <heavy-agent> or adding swap.

6. Skill integrity

# List installed skills for each running agent.
for agent in $(sudo 5dive agent list --json | jq -r '.data.agents | keys[]'); do
  echo "=== $agent ===";
  sudo 5dive agent skill "$agent" list --json | jq -r '.data.skills[].name';
done

A missing skill that the agent depends on causes silent capability gaps — not errors, just "I don't know how to do that". Re-install with:

sudo 5dive agent skill <name> add --source=<source> --skill=<skillId> --json

Putting it together — the diagnosis report

After running the checks above, produce a report in this structure:

## Diagnosis

**Status:** [Healthy / Degraded / Critical]

### Findings
- [auth] claude: authenticated ✓
- [service] agent-worker: failed — exit code 1, OOM at 03:12 UTC
- [disk] /var/lib: 87 % full — journals consuming 4.2 GB
- [skill] worker: brainstorming missing

### Root cause
<one sentence>

### Actions taken
- Vacuumed journals (freed 3.8 GB)
- Re-installed brainstorming skill on worker

### Remaining issues
- worker OOM: recommend reducing concurrent agents or adding 2 GB swap

Keep findings machine-readable (one fact per bullet, consistent prefixes) so a calling agent can parse them with agent ask.

Quick fix recipes

Restart a failed agent

sudo systemctl restart 5dive-agent@<name>
sudo 5dive agent list --json | jq '.data.agents["<name>"].status'

Free disk space fast

sudo journalctl --vacuum-size=200M
docker system prune -f 2>/dev/null || true

Re-authenticate a type

# API key (non-interactive, safe from an agent):
echo "$KEY" | sudo 5dive agent auth set <type> --api-key=- --json

# OAuth (needs a human — give them the URL):
sudo 5dive agent auth start <type> --json
# Relay the URL to the user; they paste back the callback code:
sudo 5dive agent auth submit <type> --code=<callback-code> --json

Add swap (if OOM is the culprit)

sudo fallocate -l 2G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstab

---

Security audit (explicit only — do not auto-run)

Run this block only when the user explicitly asks for a security check.

# 1. SSH authorized keys — list all keys across all users.
for f in /root/.ssh/authorized_keys /home/*/.ssh/authorized_keys; do
  [ -f "$f" ] && echo "=== $f ===" && cat "$f";
done

# 2. Open listening ports.
ss -tlnp

# 3. Recent auth failures (last 50).
sudo journalctl -u ssh -n 50 --no-pager | grep -i 'fail\|invalid\|refused'

# 4. World-writable files under /etc and /var/lib/5dive (should be empty).
find /etc /var/lib/5dive -maxdepth 4 -perm -o+w -type f 2>/dev/null

# 5. Setuid/setgid binaries not in the baseline (spot new surprises).
find / -maxdepth 5 \( -perm -4000 -o -perm -2000 \) -type f 2>/dev/null \
  | grep -v '^/usr/\|^/bin/\|^/sbin/'

# 6. Agent env files — confirm they are root-readable only.
ls -la /etc/5dive/connectors/

Report findings with a Risk label: Low, Medium, or High. Only flag deviations from the expected baseline — an empty world-writable list is a pass, not a finding.

Rules of engagement

1. Read before writing. Run checks before attempting fixes.
2. Fix one thing at a time. Each fix should be verifiable — rerun the relevant check after each action.
3. Never touch production credentials. If you find a misconfigured key, report it; don't rotate it without explicit user approval.
4. Security audit is opt-in. Never run the security section automatically.
5. Surface uncertainty. If you can't determine the root cause, say so clearly rather than guessing.