docs: add AGENTS.md with project guidelines for all agents

AGENTS.md

@@ -0,0 +1,48 @@
+# Project Guidelines
+
+## Changesets
+
+When making changes that affect the published `@dustinbyrne/kb` package, create a changeset file:
+
+```bash
+cat > .changeset/<short-description>.md << 'EOF'
+---
+"@dustinbyrne/kb": patch
+---
+
+Short description of the change.
+EOF
+```
+
+Bump types:
+- **patch**: bug fixes, internal changes
+- **minor**: new features, new CLI commands
+- **major**: breaking changes
+
+Include the changeset file in the same commit as the code change. The filename should be a short kebab-case description (e.g. `fix-merge-conflict.md`, `add-retry-button.md`).
+
+Only create changesets for changes that affect the published `@dustinbyrne/kb` package — user-facing features, bug fixes, CLI changes. Do NOT create changesets for internal docs (AGENTS.md, README), CI config, or refactors that don't change behavior.
+
+## Package Structure
+
+- `@kb/core` — domain model, task store (private, not published)
+- `@kb/dashboard` — web UI + API server (private, not published)  
+- `@kb/engine` — AI agents: triage, executor, reviewer, merger, scheduler (private, not published)
+- `@dustinbyrne/kb` — CLI entry point (published to npm)
+
+Only `@dustinbyrne/kb` is published. The others are internal workspace packages.
+
+## Testing
+
+```bash
+pnpm test          # run all tests
+pnpm build         # build all packages
+```
+
+Tests are required. Typechecks and manual verification are not substitutes for real tests with assertions.
+
+## Git
+
+- Commit messages: `feat(KB-XXX):`, `fix(KB-XXX):`, `test(KB-XXX):`
+- One commit per step (not per file change)
+- Always include the task ID prefix