feat(core): add sqlite long-term memory persistence with teach, recall, and learn

[prethiv]

Issue for this PR

Closes #48497

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Implements an SQLite-backed long-term persistence memory system for OpenCode:

1. Storage Engine (packages/core/src/memory):

   • SQLite .db persistence located in Global.Path.data (memory.db) with WAL mode.
   • SQLite FTS5 virtual table (memory_fts) with triggers for fast full-text search and BM25 ranking.
   • Core API supporting teach, recall, learn, list, get, and remove.

2. Agent Tool & Context (packages/opencode/src/tool/memory.ts):

   • Conversational memory tool registered in ToolRegistry with actions for teach, recall, learn, list, and delete.
   • System prompt instructions so agents proactively consult and persist guidelines.

3. CLI & Slash Commands (packages/opencode):

   • Registered CLI commands: opencode memory [teach|recall|learn|list|delete] with top-level aliases (opencode teach, opencode recall, opencode learn, opencode memory).
   • Registered built-in TUI slash commands: /teach, /recall, /learn, and /memory.

4. TUI Explorer Dialog (packages/tui/src/component/dialog-memory.tsx):

   • Interactive memory browser dialog wired to /memory and command palette prompt.memory.

How did you verify your code works?

1. Unit tests: Ran bun test test/memory.test.ts in packages/core (2/2 passing).
2. Integration tests: Ran bun test test/tool/memory.test.ts in packages/opencode (1/1 passing).
3. Typechecking: Ran bun turbo typecheck across all 36 workspace packages (30/30 passed).
4. CLI verification:
   • bun dev teach "Always use bun test for tests" --category "convention"
   • bun dev recall "bun test" (verified FTS5 match returned)
   • bun dev memory list (verified stored items listed)
   • bun dev learn "Insight text" --title "Test Insight"

Screenshots / recordings

Attached a screenshot or terminal recording of the /memory TUI dialog and CLI output._

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Found 2 potentially related PRs (excluding the current PR #48498):

1. PR feat(memory): add agent_memory table and memory-tools plugin #42425: feat(memory): add agent_memory table and memory-tools plugin

   • feat(memory): add agent_memory table and memory-tools plugin #42425
   • Related: Implements agent memory table and memory tools plugin, which overlaps with the memory tool and agent context components in this PR.

2. PR feat(opencode): native auto-memory for cross-session learning #20344: feat(opencode): native auto-memory for cross-session learning

   • feat(opencode): native auto-memory for cross-session learning #20344
   • Related: Addresses cross-session learning and memory persistence, which is the core goal of this PR.

These PRs may be addressing similar memory persistence and learning features. Check if they're already closed/merged or if there's overlap in implementation.

[prethiv]

Manual Testing Screenshots

[prethiv]

Summary of Review Fixes

All review comments have been resolved across core, tool, and TUI packages:

1. FTS5 & bm25 Safety & Observability (packages/core/src/memory/memory.ts):

   • initDatabase now surfaces descriptive warnings with dbPath and records errors if FTS5 setup fails.
   • Startup detection checks both hasFtsTable and hasBm25, emitting structured Effect telemetry via Effect.annotateLogs({ dbPath, fts, bm25 }).
   • Exposed fts: { available: boolean, bm25: boolean } on Memory.Interface and Service.of.
   • recall() gracefully falls back to time_created DESC or LIKE search when FTS/bm25 are unavailable.
   • Added PRAGMA user_version = 1 and documented SQLite implicit rowid semantics with content_rowid='rowid'.

2. Session Context Learning (packages/opencode/src/tool/memory.ts):

   • When learn is called without content, recent session messages are extracted, formatted into excerpts, and returned to guide the agent in distilling teachings.
   • Parameter description updated to clarify this workflow.

3. TUI Dialog Error Propagation (packages/tui/src/component/dialog-memory.tsx):

   • Replaced inner silent catch in loadMemories() with try ... finally { db.close() }, allowing database errors to properly display in the dialog's error view.

4. CI-Resilient Unit Tests (packages/core/test/memory.test.ts & packages/opencode/test/tool/memory.test.ts):

   • Tests assert boolean types (typeof memory.fts.available === "boolean") and verify end-to-end teach + recall portability across diverse SQLite builds.
   • Added test coverage for session message extraction in tool.memory.

[prethiv]

Manual tested with the latest file system and fallback copilot review fixes.