Move test database to _/tmp (cabdir)

- Document _/ directory structure in AGENTS.md - Change test database
path from .tasks/ to _/tmp/ - Update all references in tests and docs

1 files changed, 7 insertions, 0 deletions

diff --git a/AGENTS.md b/AGENTS.md
index 2656144..3c42c8c 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -38,6 +38,13 @@ task update <id> done --json
 task create "Command X fails when Y" --discovered-from=<current-task-id> --json
 ```
 
+## Directory Structure
+
+- **`_/`** (cabdir) - All ephemeral/generated files. This directory is gitignored.
+  - `_/llm/` - AI planning docs and agent logs
+  - `_/tmp/` - Temporary files, test databases, scratch data
+- Never create dotfile directories (like `.tasks/`) in the repo root
+
 ## Documentation
 
 - **Project Context**: [README.md](README.md) - Goals, source layout, and coding conventions.