## Context
Earlier today we hit a silent auth failure on the upgrade agent: the
short-lived `sk-ant-oat01-*` access token in `.credentials.json` had
expired and the CLI's refresh path failed (refresh token either stale
or invalidated after the creds sat in Vault for 5 days).
The real fix isn't "refresh more often" — it's switching to the
long-lived auth mechanism `claude setup-token` provides. Unlike
`claude login` (OAuth flow → 6–8h access token + refresh token JSON),
`setup-token` mints a single opaque token valid for **1 year** that
the CLI consumes via `CLAUDE_CODE_OAUTH_TOKEN` env var. No refresh
dance, no JSON file, no rotation for a year.
## This change
Adds `CLAUDE_CODE_OAUTH_TOKEN` to the existing
`claude-agent-secrets` ExternalSecret, sourced from a new
`claude_oauth_token` field at `secret/claude-agent-service`. The
container already pulls that secret via `envFrom`, so no other wiring
needed.
The Claude CLI prefers `CLAUDE_CODE_OAUTH_TOKEN` over the OAuth JSON
file when both are present, so this is additive — `.credentials.json`
stays mounted as a fallback while we validate the long-lived path.
Future cleanup can remove the JSON mount entirely.
Verified E2E: synthetic DIUN webhook for `docker.io/library/httpd`
→ n8n → claude-agent-service /execute → agent job `fea5ff70dcfe`
completed in 30s with exit_code=0, agent correctly identified no
matching stack and aborted without changes. No API auth errors.
## Spares
Harvested two additional long-lived tokens and stored them at
`secret/claude-agent-service-spare-{1,2}` for failover if the
primary is compromised or revoked. Verified both coexist with the
primary (no revocation on mint).
## What is NOT in this change
- No removal of `.credentials.json` mount or its Vault source (keep
as fallback until we've run for 24h on env-var auth with no issues).
- No cron rotator — 1-year TTL means this can be a yearly manual
rotation, alerted on from Vault metadata. If we add rotation, we'll
source from the spares pool rather than minting new tokens.
## Reproduce locally
```
1. vault login -method=oidc
2. vault kv get -field=claude_oauth_token secret/claude-agent-service | head -c 25
3. cd stacks/claude-agent-service && ../../scripts/tg apply
4. kubectl -n claude-agent exec deploy/claude-agent-service -- \
printenv CLAUDE_CODE_OAUTH_TOKEN # should be 108 chars
5. Fire synthetic DIUN webhook (see docs/architecture/automated-upgrades.md)
```
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
8a05475218