feat: Introduce a /reset command to clear the chat session and token tracking, and update documentation.

ChatSession.cs

@@ -34,16 +34,29 @@ internal sealed class ChatSession
                 Never include the "lineNumber:hash|" prefix in content you write — it will corrupt the file.
 
                 ## Workflow
-                1. Always read a file before editing it.
+                1. ALWAYS call GrepFile before ReadFile on any source file.
-                2. After a mutation, verify the returned fingerprint.
+                   Use patterns like "public|func|function|class|interface|enum|def|fn " to get a structural
+                   outline of the file and identify the exact line numbers of the section you need.
+                   Only then call ReadFile with a targeted startLine/endLine range.
+                   ❌ WRONG: ReadFile("Foo.cs") — reads blindly without knowing the structure.
+                   ✅ RIGHT: GrepFile("Foo.cs", "public|class|interface") → ReadFile("Foo.cs", 42, 90)
+                2. After reading, edit the file before verifying the returned fingerprint.
                 3. Edit from bottom to top so line numbers don't shift.
-                4. If an anchor fails validation, re-read the file to get fresh anchors.
+                4. If an anchor fails validation, re-read the relevant range to get fresh anchors.
 
                 Keep responses concise. You have access to the current working directory.
                 You are running on: {{System.Runtime.InteropServices.RuntimeInformation.OSDescription}}
             """)
         };
     }
+    public void Reset()
+    {
+        // Keep only the system message
+        var systemMessage = History[0];
+        History.Clear();
+        History.Add(systemMessage);
+    }
+
 
     public async IAsyncEnumerable<ChatResponseUpdate> GetStreamingResponseAsync(
         [System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken = default)

Commands/ResetCommand.cs

@@ -0,0 +1,21 @@
+using Microsoft.Extensions.AI;
+using Spectre.Console;
+using AnchorCli.OpenRouter;
+
+namespace AnchorCli.Commands;
+
+internal class ResetCommand(ChatSession session, TokenTracker tokenTracker) : ICommand
+{
+    public string Name => "reset";
+    public string Description => "Reset the chat session (clear history and token count)";
+
+    public Task ExecuteAsync(string[] args, CancellationToken ct)
+    {
+        session.Reset();
+        tokenTracker.Reset();
+        AnsiConsole.MarkupLine("[green]Chat session reset.[/]");
+        return Task.CompletedTask;
+    }
+}
+
+

ContextCompactor.cs

@@ -29,10 +29,6 @@ internal sealed partial class ContextCompactor(IChatClient client)
     /// A 300-line ReadFile result (~10K tokens) becomes a one-line note (~20 tokens).
     /// </summary>
     /// <param name="history">The chat history to compact in-place.</param>
-    /// <param name="currentTurnStartIndex">
-    /// Index of the first message added during the current turn.
-    /// Messages before this index are from previous turns and eligible for compaction.
-    /// </param>
     /// <returns>Number of tool results that were compacted.</returns>
     public static int CompactStaleToolResults(List<ChatMessage> history)
     {

OpenRouter/TokenTracker.cs

@@ -34,6 +34,14 @@ internal sealed class TokenTracker
         LastInputTokens = inputTokens;
         RequestCount++;
     }
+    public void Reset()
+    {
+        SessionInputTokens = 0;
+        SessionOutputTokens = 0;
+        RequestCount = 0;
+        LastInputTokens = 0;
+    }
+
 
     private const int MaxContextReserve = 150_000;
 

Program.cs

@@ -127,6 +127,8 @@ commandRegistry.Register(new ClearCommand());
 commandRegistry.Register(new StatusCommand(model, endpoint));
 commandRegistry.Register(new CompactCommand(session.Compactor, session.History));
 commandRegistry.Register(new SetupCommand());
+commandRegistry.Register(new ResetCommand(session, tokenTracker));
+
 
 var commandDispatcher = new CommandDispatcher(commandRegistry);
 
@@ -134,3 +136,4 @@ var commandDispatcher = new CommandDispatcher(commandRegistry);
 
 var repl = new ReplLoop(session, tokenTracker, commandDispatcher);
 await repl.RunAsync();
+

README.md

@@ -22,7 +22,7 @@ This eliminates:
 ## Features
 
 - **Interactive REPL**: Chat with an AI model to edit files, manage directories, and execute commands
-- **Slash Commands**: `/setup`, `/help`, `/exit`, `/clear`, `/status`, `/compact`
+- **Slash Commands**: `/setup`, `/help`, `/exit`, `/clear`, `/status`, `/compact`, `/reset`
 - **Token Tracking**: Real-time token usage and cost per response, plus session totals
 - **Model Pricing Display**: Shows current model pricing from OpenRouter in the header
 - **Context Compaction**: Automatic conversation history compression when approaching context limits, including stale tool result compaction
@@ -69,7 +69,7 @@ The resulting binary is ~12 MB, has no .NET runtime dependency, and starts insta
 | `/clear` | Clear the conversation history |
 | `/status` | Show session token usage and cost |
 | `/compact` | Manually trigger context compaction |
-
+| `/reset` | Clear session and reset token tracker |
 ## Available Tools
 
 **File Operations:**
@@ -98,31 +98,37 @@ The resulting binary is ~12 MB, has no .NET runtime dependency, and starts insta
 **Command Execution:**
 - `execute_command` - Run shell commands (with user approval)
 
-## Project Structure
-
 ```
 AnchorCli/
-├── Program.cs              # Entry point + REPL loop + AI client setup
+├── Program.cs              # Entry point + CLI parsing
-├── AnchorConfig.cs        # JSON file-based configuration (~APPDATA~\anchor\config.json)
+├── ReplLoop.cs             # Main REPL loop with streaming, spinners, and cancellation
-├── ContextCompactor.cs    # Conversation history compression
+├── ChatSession.cs          # AI chat client wrapper with message history
-├── AppJsonContext.cs      # Source-generated JSON context (AOT)
+├── ToolRegistry.cs         # Centralized tool registration and dispatch
+├── AnchorConfig.cs         # JSON file-based configuration (~APPDATA~/anchor/config.json)
+├── ContextCompactor.cs     # Conversation history compression
+├── AppJsonContext.cs       # Source-generated JSON context (AOT)
+├── SetupTui.cs             # Interactive setup TUI
 ├── Hashline/
-│   ├── HashlineEncoder.cs  # Adler-8 + position-seed hashing
+│   ├── HashlineEncoder.cs   # Adler-8 + position-seed hashing
 │   └── HashlineValidator.cs # Anchor resolution + validation
 ├── Tools/
-│   ├── FileTools.cs        # read_file, grep_file, grep_recursive, find_files, get_file_info
+│   ├── FileTools.cs         # read_file, grep_file, grep_recursive, find_files, get_file_info
-│   ├── EditTools.cs        # replace_lines, insert_after, delete_range, create/delete/rename/copy/append
+│   ├── EditTools.cs         # replace_lines, insert_after, delete_range, create/delete/rename/copy/append
-│   ├── DirTools.cs         # list_dir, create_dir, rename_dir, delete_dir
+│   ├── DirTools.cs          # list_dir, create_dir, rename_dir, delete_dir
-│   └── CommandTool.cs      # execute_command
+│   └── CommandTool.cs       # execute_command
 ├── Commands/
-│   ├── ExitCommand.cs      # /exit command
+│   ├── ICommand.cs          # Command interface
-│   ├── HelpCommand.cs      # /help command
+│   ├── CommandRegistry.cs   # Command registration
-│   ├── ClearCommand.cs     # /clear command
+│   ├── CommandDispatcher.cs # Command dispatch logic
-│   ├── StatusCommand.cs    # /status command
+│   ├── ExitCommand.cs       # /exit command
-│   └── CompactCommand.cs   # /compact command
+│   ├── HelpCommand.cs       # /help command
-├── OpenRouter/
+│   ├── ClearCommand.cs      # /clear command
-│   └── PricingProvider.cs  # Fetch model pricing from OpenRouter
+│   ├── StatusCommand.cs     # /status command
-└── SetupTui.cs            # Interactive setup TUI
+│   ├── CompactCommand.cs    # /compact command
+│   ├── ResetCommand.cs      # /reset command
+│   └── SetupCommand.cs      # /setup command
+└── OpenRouter/
+    └── PricingProvider.cs   # Fetch model pricing from OpenRouter
 ```
 
 ## How It Works

ReplLoop.cs

@@ -64,8 +64,8 @@ internal sealed class ReplLoop
                     if (update.RawRepresentation is OpenAI.Chat.StreamingChatCompletionUpdate raw
                         && raw.Usage != null)
                     {
-                        respIn += raw.Usage.InputTokenCount;
+                        respIn = raw.Usage.InputTokenCount;   // last call = actual context size
-                        respOut += raw.Usage.OutputTokenCount;
+                        respOut += raw.Usage.OutputTokenCount; // additive — each round generates new output
                     }
                 }
 
@@ -88,6 +88,13 @@ internal sealed class ReplLoop
                         showSpinner = true;
                     }
                 };
+                FileTools.OnFileRead = _ =>
+                {
+                    int n = ContextCompactor.CompactStaleToolResults(_session.History);
+                    if (n > 0)
+                        AnsiConsole.MarkupLine(
+                            $"[dim grey]  ♻ Compacted {n} stale tool result(s)[/]");
+                };
 
                 var spinnerTask = Task.Run(async () =>
                 {
@@ -143,6 +150,7 @@ internal sealed class ReplLoop
                     await Task.WhenAny(spinnerTask);
                     CommandTool.PauseSpinner = null;
                     CommandTool.ResumeSpinner = null;
+                    FileTools.OnFileRead = null;
                 }
 
                 if (firstChunk != null)
@@ -184,13 +192,6 @@ internal sealed class ReplLoop
 
                 _session.History.Add(new ChatMessage(ChatRole.Assistant, fullResponse));
 
-                int compactedResults = ContextCompactor.CompactStaleToolResults(_session.History);
-                if (compactedResults > 0)
-                {
-                    AnsiConsole.MarkupLine(
-                        $"[dim grey]  ♻ Compacted {compactedResults} stale tool result(s) from previous turns[/]");
-                }
-
                 if (_tokenTracker.ShouldCompact())
                 {
                     var pct = _tokenTracker.ContextUsagePercent;

SANDBOX.md

@@ -0,0 +1,334 @@
+# Sandbox Implementation Plan for AnchorCli
+
+## Overview
+
+By default, all file and directory operations are restricted to the current working directory (CWD).
+Users can bypass this restriction with the `--no-sandbox` flag.
+
+## Usage
+
+```bash
+# Default: sandbox enabled (operations limited to CWD)
+anchor
+
+# Disable sandbox (allow operations anywhere)
+anchor --no-sandbox
+```
+
+## Architecture
+
+The implementation leverages the existing `ResolvePath()` methods in `FileTools` and `DirTools`.
+Since tools are static classes without dependency injection, we use a static `SandboxContext` class.
+
+---
+
+## Implementation Steps
+
+### Step 1: Create `SandboxContext.cs`
+
+Create a new file `Core/SandboxContext.cs`:
+
+```csharp
+using System;
+
+namespace AnchorCli;
+
+/// <summary>
+/// Static context holding sandbox configuration.
+/// Checked by ResolvePath() to validate paths are within working directory.
+/// </summary>
+internal static class SandboxContext
+{
+    private static string? _workingDirectory;
+    private static bool _enabled = true;
+
+    public static bool Enabled
+    {
+        get => _enabled;
+        set => _enabled = value;
+    }
+
+    public static string WorkingDirectory
+    {
+        get => _workingDirectory ?? Environment.CurrentDirectory;
+        set => _workingDirectory = value;
+    }
+
+    /// <summary>
+    /// Validates that a resolved path is within the working directory (if sandbox is enabled).
+    /// Returns the resolved path if valid, or null if outside sandbox (no exception thrown).
+    /// When null is returned, the calling tool should return an error message to the agent.
+    /// </summary>
+    public static string? ValidatePath(string resolvedPath)
+    {
+        if (!_enabled)
+            return resolvedPath;
+        
+        var workDir = WorkingDirectory;
+        
+        // Normalize paths for comparison
+        var normalizedPath = Path.GetFullPath(resolvedPath).TrimEnd(Path.DirectorySeparatorChar);
+        var normalizedWorkDir = Path.GetFullPath(workDir).TrimEnd(Path.DirectorySeparatorChar);
+
+        // Check if path starts with working directory
+        if (!normalizedPath.StartsWith(normalizedWorkDir, StringComparison.OrdinalIgnoreCase))
+        {
+            // Return null to signal violation - caller handles error messaging
+            return null;
+        }
+
+        return resolvedPath;
+    }
+
+    public static void Initialize(bool sandboxEnabled)
+    {
+        _enabled = sandboxEnabled;
+        _workingDirectory = Environment.CurrentDirectory;
+    }
+}
+```
+
+---
+
+### Step 2: Modify `Program.cs`
+
+Add argument parsing and initialize the sandbox context:
+
+**After line 15** (after the `setup` subcommand check), add:
+
+```csharp
+// ── Parse sandbox flag ──────────────────────────────────────────────────
+bool sandboxEnabled = !args.Contains("--no-sandbox");
+SandboxContext.Initialize(sandboxEnabled);
+
+if (!sandboxEnabled)
+{
+    AnsiConsole.MarkupLine("[dim grey]Sandbox disabled (--no-sandbox)[/]");
+}
+```
+
+---
+
+### Step 3: Update `FileTools.ResolvePath()`
+
+**Replace lines 322-323** with:
+
+    internal static string? ResolvePath(string path, out string? errorMessage)
+    {
+        errorMessage = null;
+        var resolved = Path.IsPathRooted(path) 
+            ? path 
+            : Path.GetFullPath(path, Environment.CurrentDirectory);
+        
+        var validated = SandboxContext.ValidatePath(resolved);
+        if (validated == null)
+        {
+            errorMessage = $"Sandbox violation: Path '{path}' is outside working directory '{SandboxContext.WorkingDirectory}'. Use --no-sandbox to disable restrictions.";
+            return null;
+        }
+        
+        return validated;
+    }
+
+---
+
+### Step 4: Update `DirTools.ResolvePath()`
+
+**Replace lines 84-85** with:
+
+```csharp
+    internal static string? ResolvePath(string path, out string? errorMessage)
+    {
+        errorMessage = null;
+        var resolved = Path.IsPathRooted(path) 
+            ? path 
+            : Path.GetFullPath(path, Environment.CurrentDirectory);
+        
+        var validated = SandboxContext.ValidatePath(resolved);
+        if (validated == null)
+        {
+            errorMessage = $"Sandbox violation: Path '{path}' is outside working directory '{SandboxContext.WorkingDirectory}'. Use --no-sandbox to disable restrictions.";
+            return null;
+        }
+        
+        return validated;
+    }
+
+---
+
+### Step 5: Update Tool Descriptions (Optional but Recommended)
+
+Update the `[Description]` attributes to mention sandbox behavior:
+
+**FileTools.cs - ReadFile** (line 23):
+```csharp
+[Description("Read a file. Max 200 lines per call. Returns lines with line:hash| anchors. Sandbox: restricted to working directory unless --no-sandbox is used. IMPORTANT: Call GrepFile first...")]
+```
+
+**DirTools.cs - CreateDir** (line 63):
+```csharp
+[Description("Create a new directory. Creates parent directories if they don't exist. Sandbox: restricted to working directory unless --no-sandbox is used. Returns OK on success...")]
+```
+
+Repeat for other tools as needed.
+
+---
+
+## How Tools Handle Sandbox Violations
+
+Each tool that uses `ResolvePath()` must check for `null` return and handle it gracefully:
+
+### FileTools Pattern
+
+```csharp
+// Before (old code):
+var resolvedPath = ResolvePath(path);
+var content = File.ReadAllText(resolvedPath);
+
+// After (new code):
+var resolvedPath = ResolvePath(path, out var errorMessage);
+if (resolvedPath == null)
+    return $"ERROR: {errorMessage}";
+    
+var content = File.ReadAllText(resolvedPath);
+```
+
+### DirTools Pattern
+
+```csharp
+// Before (old code):
+var resolvedPath = ResolvePath(path);
+Directory.CreateDirectory(resolvedPath);
+
+// After (new code):
+var resolvedPath = ResolvePath(path, out var errorMessage);
+if (resolvedPath == null)
+    return $"ERROR: {errorMessage}";
+    
+Directory.CreateDirectory(resolvedPath);
+return "OK";
+```
+
+### EditTools
+
+No changes needed - it already calls `FileTools.ResolvePath()`, so the sandbox check happens there.
+
+### Tools That Don't Use ResolvePath
+
+- `ListDir` with no path argument (uses current directory)
+- `GetFileInfo` - needs to be updated to use `ResolvePath()`
+- `FindFiles` - needs to be updated to validate the search path
+
+---
+---
+
+## Error Handling - No Crashes
+
+When a sandbox violation occurs, the program **does not crash**. Instead:
+
+1. `ResolvePath()` returns `null` and sets `errorMessage`
+2. The tool returns the error message to the agent
+3. The agent sees the error and can continue the conversation
+4. The user sees a clear error message in the chat
+
+**Example tool implementation pattern:**
+
+```csharp
+public static async Task<string> ReadFile(string path, int startLine, int endLine)
+{
+    var resolvedPath = ResolvePath(path, out var errorMessage);
+    if (resolvedPath == null)
+        return $"ERROR: {errorMessage}";  // Return error, don't throw
+    
+    // ... rest of the tool logic
+}
+```
+
+**What the agent sees:**
+```
+Tool result: ERROR: Sandbox violation: Path '/home/tomi/.ssh' is outside working directory '/home/tomi/dev/anchor'. Use --no-sandbox to disable restrictions.
+```
+
+**What the user sees in chat:**
+> The agent tried to read `/home/tomi/.ssh` but was blocked by the sandbox. The agent can now adjust its approach or ask you to run with `--no-sandbox`.
+
+---
+
+## Edge Cases Handled
+
+| Case | Behavior |
+|------|----------|
+| **Symlinks inside CWD pointing outside** | Follows symlink (user-created link = intentional) |
+| **Path traversal (`../..`)** | Blocked if result is outside CWD |
+| **Absolute paths** | Validated against CWD |
+| **Network paths** | Blocked (not under CWD) |
+| **Case sensitivity** | Uses `OrdinalIgnoreCase` for cross-platform compatibility |
+
+---
+
+## Security Notes
+
+⚠️ **The sandbox is a safety feature, not a security boundary.**
+
+- It prevents **accidental** modifications to system files
+- It does **not** protect against malicious intent
+- `CommandTool.ExecuteCommand()` can still run arbitrary shell commands
+- A determined user can always use `--no-sandbox`
+
+For true isolation, run anchor in a container or VM.
+
+---
+
+## Testing Checklist
+
+- [ ] `ReadFile` on file inside CWD → **Success**
+- [ ] `ReadFile` on file outside CWD → **Sandbox violation error**
+- [ ] `ReadFile` with `../` traversal outside CWD → **Sandbox violation error**
+- [ ] `CreateDir` outside CWD → **Sandbox violation error**
+- [ ] `anchor --no-sandbox` then read `/etc/passwd` → **Success**
+- [ ] Symlink inside CWD pointing to `/etc/passwd` → **Success** (user-created link)
+- [ ] Case variations on Windows (`C:\Users` vs `c:\users`) → **Success**
+
+---
+
+## Migration Guide
+
+### Existing Workflows
+
+If you have scripts or workflows that rely on accessing files outside the project:
+
+```bash
+# Update your scripts to use --no-sandbox
+anchor --no-sandbox
+```
+
+### CI/CD Integration
+
+For CI environments where sandbox may not be needed:
+
+```yaml
+# GitHub Actions example
+- name: Run anchor
+  run: anchor --no-sandbox
+```
+
+---
+
+## Files Modified
+
+| File | Changes |
+|------|---------|
+| `Core/SandboxContext.cs` | **New file** - Static sandbox state and validation |
+| `Program.cs` | Add `--no-sandbox` parsing, call `SandboxContext.Initialize()` |
+| `Tools/FileTools.cs` | Update `ResolvePath()` signature to return `string?` with `out errorMessage`; update all tool methods to check for null |
+| `Tools/DirTools.cs` | Update `ResolvePath()` signature to return `string?` with `out errorMessage`; update all tool methods to check for null |
+| `Tools/EditTools.cs` | No changes (uses `FileTools.ResolvePath()`, sandbox check happens there) |
+| `Tools/CommandTool.cs` | **Not sandboxed** - shell commands can access any path (documented limitation) |
+---
+
+## Future Enhancements
+
+- **Allowlist**: Let users specify additional safe directories via config
+- **Per-tool sandbox**: Some tools (e.g., `GrepRecursive`) could have different rules
+- **Audit mode**: Log all file operations for review
+- **Interactive prompt**: Ask for confirmation before violating sandbox instead of hard fail

Tools/FileTools.cs

@@ -14,7 +14,13 @@ internal static class FileTools
 {
     public static Action<string> Log { get; set; } = Console.WriteLine;
 
-    [Description("Read a file. Max 200 lines per call. Returns lines with line:hash| anchors.")]
+    /// <summary>
+    /// Optional callback invoked after each successful ReadFile call, with the resolved path.
+    /// Set by ReplLoop to trigger deduplication compaction while the tool loop is still active.
+    /// </summary>
+    public static Action<string>? OnFileRead { get; set; }
+
+    [Description("Read a file. Max 200 lines per call. Returns lines with line:hash| anchors. IMPORTANT: Call GrepFile first (pattern: 'public|class|func|interface|enum|def') to get a structural outline and target startLine/endLine before calling this.")]
     public static string ReadFile(
         [Description("Path to the file.")] string path,
         [Description("First line to return (inclusive). Defaults to 1.")] int startLine = 1,
@@ -40,7 +46,9 @@ internal static class FileTools
                 return $"ERROR: File too large to read at once ({lines.Length} lines). Provide startLine and endLine to read a chunk of max 200 lines. Use GrepFile to get an outline (grep 'public') and find the line numbers.";
             }
 
-            return HashlineEncoder.Encode(lines, startLine, endLine);
+            string result = HashlineEncoder.Encode(lines, startLine, endLine);
+            OnFileRead?.Invoke(path);
+            return result;
         }
         catch (Exception ex)
         {