Seal the four credential columns with AES-256-GCM (random nonce per value,
AAD "<table>.<column>"): llm_profiles.api_key and task_credentials.password
store "enc:v1:<base64(nonce||ciphertext)>"; mcp_servers.env and
notification_channels.config store {"__artex_enc":"enc:v1:..."} over the
canonical JSON. The db layer encrypts on write and decrypts on read, so agent
tools (LLM provider, MCP, notifier, test credentials) get plaintext
server-side. Decryption failure is an error, never a plaintext fallback.
Key: ARTEX_SECRET_KEY (32 bytes, base64 or hex) or keys/secret.key next to
jwt.key, generated with crypto/rand at first start (0600). Startup refuses
when encrypted values exist and no key is available, and when the key does
not decrypt them. An idempotent backfill under the schema advisory lock
encrypts legacy plaintext rows and logs only a count.
API: MCP env is masked on read and masked placeholders on write keep the
stored value; task credential passwords are masked server-side and a masked
password on write is refused. ARTEX_SECRET_KEY is scrubbed from the process
environment with the other startup secrets.
agent, db, server and evidence serialized on one shared test database via an advisory lock, while evidence, llmrec and traffic-style packages could still run against it in parallel; under full-suite load that window produced a real SQLSTATE 40P01 deadlock in the blackboard direct-source test. TestMain in every PG-using package now rewrites ARTEX_PG_DSN to a per-package database (created automatically by ensureDatabase), so packages neither contend nor need to serialize; the advisory lock stays as an in-package safety net. llmrec gains the TestMain it lacked, which also gives its requires-isolated-DSN tests a truly isolated database inside ./... runs.