Adds agent rules.

AGENTS.md

@@ -0,0 +1,50 @@
+# Agent Workflow & Project Guidelines
+
+This document defines the operating rules, task lifecycle, and development conventions for AI agents and contributors working in the **Nextcloud Upload Tool** repository.
+
+---
+
+## 1. Core Operating Rules
+
+### Single-Task Execution
+- **Strictly one task at a time**: Never bundle multiple tasks or implement features outside the currently assigned task.
+- **Workflow Steps**:
+  1. Inspect [Tasks.md](file:///Users/tom/Projects/Apps/NextcloudUploadTool/Tasks.md) to identify the next prioritized task.
+  2. Transition the task status to `in_progress` in [Tasks.md](file:///Users/tom/Projects/Apps/NextcloudUploadTool/Tasks.md).
+  3. Implement only the requirements specified in that task's checklist.
+  4. Verify changes using the test and build suite (`cargo test --workspace` and frontend build in `gui`).
+  5. Update [Tasks.md](file:///Users/tom/Projects/Apps/NextcloudUploadTool/Tasks.md) to mark the task `done` (Fixed), checking off completed requirements and updating the summary table.
+  6. Pause and present results to the user for review and git commit. Do not proceed to the next task until the user acknowledges.
+
+### Git Operations
+- **User-Managed Commits**: All `git commit`, branching, rebasing, resets, and destructive git commands are handled exclusively by the user.
+- **Agent Git Scope**:
+  - Allowed: Read-only inspection (`git status`, `git diff`, `git log`) and staging (`git add`, `git rm`) if needed.
+  - Forbidden: Making commits, modifying files under `.git/`, or modifying git history.
+
+### Environment & Build Commands
+- Node version: Node 20 as specified in [`.nvmrc`](file:///Users/tom/Projects/Apps/NextcloudUploadTool/.nvmrc).
+- Backend tests: `cargo test --workspace`
+- Frontend build: `cd gui && npm run build`
+
+---
+
+## 2. Tasks.md Maintenance Rules
+
+### Single Source of Truth (SSOT)
+- **Anchor Tags**: `<a id="nut-xxx" class="task" data-status="..." data-task-type="..."></a>` directly above each task heading is the SSOT for machine-readable attributes (`id`, `data-status`, `data-task-type`).
+- **Task Details**: The markdown body under each heading is the SSOT for title, description, checklist items (`- [x]`), and direct dependencies.
+
+### Invariant Ordering
+- **Tasks Summary Table**:
+  - Open/Active tasks (`triage`, `pending`, `in_progress`, `blocked`) are listed at the top.
+  - Completed (`done` / Fixed) tasks are listed at the bottom, sorted in **ascending numeric order** (`NUT-001`, `NUT-002`, ...).
+- **Detailed Tasks Section**:
+  - All detailed task entries must remain in **strict monotonic numeric ascending order** (`NUT-001`, `NUT-002`, `NUT-003`, ...).
+  - Use two blank lines between detailed task blocks.
+
+---
+
+## 3. Communication & Code Style
+- Always use clickable GitHub-style file links (`[file.rs](file:///path/to/file.rs)`) and symbol links when referencing files or types in responses.
+- Keep responses focused, concise, and aligned with the single task being executed.