A Personality is a named overlay on top of an Agent — same agent,
same LLM, but a different bundle of prompts injected into the system
block at chat time. VLAN-on-ethernet semantics: ethernet still works
without VLAN; with a VLAN tag, frames are segmented but still ethernet.
Schema additions:
- Prompt.agentId (nullable FK + index, cascade on delete) so prompts
can attach directly to an agent without going through a project.
- Personality { id, name, description, agentId, priority } with
unique (name, agentId).
- PersonalityPrompt join table with per-binding priority override.
- Agent.defaultPersonalityId (SetNull on delete) so an agent can pick
one personality as the default when no --personality flag is passed.
Backwards-compatible by construction: every new column is nullable;
existing rows are valid as-is; the chat.service systemBlock changes
land in Stage 3.
8 new prisma-level assertions in agent-schema.test.ts cover unique
constraints, cascade behavior, the SetNull on defaultPersonalityId,
and shared-prompt-across-personalities. All 16 db tests pass; mcpd
typecheck + 777 mcpd unit tests still green.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Introduces the persistence layer for the upcoming Agent feature: an LLM
persona pinned to a specific Llm, optionally attached to a Project, with
persisted chat threads/messages so conversations survive REPL exits.
Constraint shape:
- Agent.llm uses ON DELETE RESTRICT — deleting an Llm in active use fails.
- Agent.project uses ON DELETE SET NULL — agents survive project deletion.
- ChatThread → ChatMessage cascade so deleting an agent purges its history.
- ChatMessage @@unique([threadId, turnIndex]) gives append ordering even
under racing writers (services retry on collision).
LiteLLM-style per-call overrides will live in Agent.defaultParams (Json);
the loose extras Json field is reserved for future LoRA/tool-allowlist work.
Pinned vitest fileParallelism=false in @mcpctl/db: all suites share the
same Postgres, and adding a second suite exposed FK contention between a
clearAllTables in one file and a create in another. Per-test isolation
still comes from beforeEach.
Tests: 8/8 green in src/db/tests/agent-schema.test.ts (defaults, name
uniqueness, llm-in-use Restrict, project-delete SetNull, agent-delete
cascade, duplicate (threadId, turnIndex) blocked, tool-call payload
round-trip, lastTurnAt DESC ordering).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
