```                   # 📋 Session Report
    λλ              
   λ⊙λ⊙             
  λλλλλλ            
 λλλλλλλλ           
    λλ              
    λλ              
    λλ              
    λλ              
    λλ              
    λλ              
    λλ              
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```                 

**🔑 Session ID:** 568b295e-5d12-487d-a115-9f9fb6e0f310

---

## 📊 Statistics

### Turn Counts

| Metric | Value |
|--------|-------|
| Total Turns | 36 |
| 👤 User Turns | 18 |
| 🤖 LLM Turns | 18 |

### 🔧 Tool Calls

**Total Tool Calls:** 17

`bash_check-code     `    5 ████████████████████████████████████████████████████████████

`bash_read-file      `    4 ████████████████████████████████████████████████

`bash_write-file     `    4 ████████████████████████████████████████████████

`bash_grep-files     `    3 ████████████████████████████████████

`bash_list-files     `    1 ████████████


### 💾 Byte Usage

`Input     `    129 KiB ████████████████████████████████████████████████████████████

`Output    `      2 KiB █

`Reasoning `      4 KiB ██
**Total:** 136 KiB

---

## 👤 Step 1: User Turn

### 📝 System Prompt

```
You are an expert Haskell and Bash programmer specialized in writing clean, idiomatic, and efficient Haskell code.
When writing Bash code:
- Avoid bash-specific logic but bash-ism are fine.
- Document required shell tools at the top of the bash script.
When writing Haskell code:
- Use modern Haskell practices (base >= 4.14)
- Prefer pure functions and explicit type signatures
- Use standard libraries when appropriate
- Add clear comments for complex logic
- Follow consistent formatting
Use list-files to explore the project structure, read-file to understand existing code, write-file to create or modify files, and check-code to verify your work.
Always compile code before considering the job done.
Your output format may be stored as commit message: hence the first line of your last message should be a summary line.
```

### 💬 User Query

# Add synchronization mechanism for MCP tool discovery

# Add synchronization mechanism for MCP tool discovery

## Problem

The MCP toolbox initialization is asynchronous - tools are discovered via the MCP client loop after `initializeMcpToolbox` returns. Currently there's no way to wait for initial tool discovery to complete, which can lead to race conditions where agents start with incomplete tool sets.

## Current Behavior

In `src/System/Agents/Tools/McpToolbox.hs`:

```haskell
initializeMcpToolbox :: Tracer IO Trace -> Text -> CreateProcess -> IO Toolbox
initializeMcpToolbox ttracer tname proc = do
    -- ...
    mcpRt <- McpClient.initRuntime rtTracer proc
    let props = LoopProps loopTracer nextToolCall
    ajob <- async (McpClient.runClient clientTracer mcpRt (McpClient.defaultLoop props))
    pure $ Toolbox tname ajob discoveredTools doCallTool
    -- ^ Returns immediately, tools may not be discovered yet!
```

## Desired Behavior

Provide a mechanism to wait for initial tool discovery before the toolbox is used.

## Proposed Solution

Add a synchronization primitive to the `Toolbox` type:

```haskell
data Toolbox = Toolbox
    { name :: Text
    , job :: Async ()
    , toolsList :: TVar [ToolDescription]
    , callTool :: ToolDescription -> Maybe Aeson.Object -> IO (McpClient.ToolCallResponse)
    , initialDiscoveryDone :: MVar ()  -- ^ NEW: signals when first discovery completes
    }

-- NEW: Function to wait for initial discovery
waitForInitialDiscovery :: Toolbox -> IO ()
waitForInitialDiscovery = readMVar . initialDiscoveryDone
```

The `storeToolsInDiscoveredValues` tracer should populate this MVar when the first `ToolsRefreshed` event is received.

## Tradeoffs

- **Complexity**: Adds another concurrency primitive to manage
- **Timeout**: Should consider adding a timeout to prevent indefinite blocking
- **Partial failure**: What if some toolboxes succeed and others fail?

## Files to Modify

- `src/System/Agents/Tools/McpToolbox.hs` - Add synchronization primitive and wait function

## Acceptance Criteria

- [ ] `Toolbox` contains a synchronization mechanism for initial discovery
- [ ] `waitForInitialDiscovery` function exported and documented
- [ ] Tracer populates the synchronization primitive on first `ToolsRefreshed`
- [ ] Edge cases handled (MCP server disconnect, timeout, etc.)

## Priority

High - This addresses a race condition that can cause agents to start with incomplete tool sets.

## Key Data Types

```haskell
-- From src/System/Agents/Tools/McpToolbox.hs
data Toolbox = Toolbox
    { name :: Text
    , job :: Async ()
    , toolsList :: TVar [ToolDescription]
    , callTool :: ToolDescription -> Maybe Aeson.Object -> IO (McpClient.ToolCallResponse)
    }

newtype ToolDescription = ToolDescription {getToolDescription :: Mcp.Tool}
    deriving (Show)

data Trace
    = McpClientRunTrace !McpClient.RunTrace
    | McpClientClientTrace !McpClient.ClientTrace
    | McpClientLoopTrace !McpClient.LoopTrace
    deriving (Show)
```

---
From #332



### 🛠️ Available Tools

- **bash_grep-files** (`bash_grep-files`)
  - Description: Search for a pattern in files using 'git grep'
- **bash_read-file** (`bash_read-file`)
  - Description: Read the contents of a file
- **bash_write-file** (`bash_write-file`)
  - Description: Write content to a file
- **bash_check-code** (`bash_check-code`)
  - Description: Check Haskell code by compiling or testing
- **bash_list-files** (`bash_list-files`)
  - Description: List all files in the project

---

## 🤖 Step 2: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

Let me start by exploring the project structure and understanding the existing code to implement the synchronization mechanism for MCP tool discovery.
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_list-files**

---

## 👤 Step 3: User Turn



---

## 🤖 Step 4: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

Now let me read the main file that needs to be modified: `src/System/Agents/Tools/McpToolbox.hs`
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_read-file**

---

## 👤 Step 5: User Turn



---

## 🤖 Step 6: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

Now let me look at the MCP Client module to understand the `LoopTrace` type and how `ToolsRefreshed` is triggered.
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_read-file**

---

## 👤 Step 7: User Turn



---

## 🤖 Step 8: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

Now I understand the codebase better. Let me check if there's anything else I need to look at to understand the imports and patterns used in the project.

Looking at the code:
1. `Toolbox` currently has 4 fields
2. `ToolsRefreshed` is triggered when tools are first discovered (either via notification or polling)
3. We need to add an `MVar ()` to signal when the initial discovery is done
4. The `storeToolsInDiscoveredValues` tracer needs to be modified to populate this MVar

Let me also look at what the module exports to understand what we need to export.
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_grep-files**

---

## 👤 Step 9: User Turn



---

## 🤖 Step 10: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

The module exports everything (no explicit export list). Now let me implement the solution:

1. Add `initialDiscoveryDone :: MVar ()` to the `Toolbox` type
2. Create `waitForInitialDiscovery :: Toolbox -> IO ()` function
3. Modify `storeToolsInDiscoveredValues` to accept an `MVar ()` and populate it on first `ToolsRefreshed`
4. Modify `initializeMcpToolbox` to create the MVar and pass it to the tracer

Let me write the updated file.
</details>

### 💬 Response

Now I understand the structure. Let me implement the synchronization mechanism:

### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 11: User Turn



---

## 🤖 Step 12: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

Now let me compile the code to make sure it works correctly.
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_check-code**

---

## 👤 Step 13: User Turn



---

## 🤖 Step 14: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

I need to fix the import issues. Let me update the imports:
1. Add `takeMVar` to the MVar imports
2. Add `void` import from `Control.Monad`
3. Need to add type signature for the `extractToolDescriptions` function

Let me fix these issues.
</details>

### 💬 Response

I need to fix a few import issues. Let me update the file:

### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 15: User Turn



---

## 🤖 Step 16: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

Now let me compile again to see if it works.
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_check-code**

---

## 👤 Step 17: User Turn



---

## 🤖 Step 18: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

The issue is with the record dot syntax. I need to use a different approach for accessing the fields. Let me look at how the original code worked and use that approach. The original code was:

```haskell
g (Just (Right rsp)) = fmap ToolDescription rsp.getListToolsResult.tools
```

This uses the `HasField` type class which requires `FlexibleContexts`. Let me use pattern matching or accessor functions instead.
</details>

### 💬 Response

I need to use explicit accessor functions instead of record dot syntax. Let me fix this:

### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 19: User Turn



---

## 🤖 Step 20: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

Let me compile again.
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_check-code**

---

## 👤 Step 21: User Turn



---

## 🤖 Step 22: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

I see, I need to understand the types better. Let me look at how the original code was accessing these fields. It looks like the record accessors are actually functions that need to be composed properly. Let me look at the original code again.

Original code:
```haskell
g (Just (Right rsp)) = fmap ToolDescription rsp.getListToolsResult.tools
```

The issue is that `getListToolsResult` and `tools` are field accessors that use GHC's record dot preprocessor. I should look at the actual type definitions.
</details>

### 💬 Response

Let me check the original code and the types more carefully:

### 🔧 Tool Calls

- **bash_grep-files**

---

## 👤 Step 23: User Turn



---

## 🤖 Step 24: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

I see - the original code uses record dot syntax which requires GHC's `OverloadedRecordDot` extension. Let me check the structure of `Mcp.ListToolsResult`:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_grep-files**

---

## 👤 Step 25: User Turn



---

## 🤖 Step 26: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

Let me look at the Mcp.Base module:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_read-file**

---

## 👤 Step 27: User Turn



---

## 🤖 Step 28: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

I see the issue. The record dot syntax is being used and it requires proper composition. Let me look at the original code again and see how the accessor was working.

Looking at the original:
```haskell
g (Just (Right rsp)) = fmap ToolDescription rsp.getListToolsResult.tools
```

Here, `rsp` is a `ListToolsResultRsp`, `getListToolsResult` is a record accessor that returns `Mcp.ListToolsResult`, and `tools` is a field of `Mcp.ListToolsResult` that returns `[Tool]`.

So the composition is:
1. `rsp.getListToolsResult` returns `ListToolsResult`
2. `.tools` on `ListToolsResult` returns `[Tool]`

Let me rewrite this using regular function composition:
</details>

### 💬 Response

I see the issue. The original code uses record dot syntax. Let me fix the accessor properly:

### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 29: User Turn



---

## 🤖 Step 30: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

Now let me compile again.
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_check-code**

---

## 👤 Step 31: User Turn



---

## 🤖 Step 32: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

The code compiles successfully. Now let me run the tests to make sure everything works properly.
</details>

### 💬 Response

The code compiles. Let me run the tests to make sure everything is working:

### 🔧 Tool Calls

- **bash_check-code**

---

## 👤 Step 33: User Turn



---

## 🤖 Step 34: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

All tests pass. Let me verify the final implementation by reading the file one more time to ensure it's complete and properly documented.
</details>

### 💬 Response

All tests pass. Let me verify the final implementation:

### 🔧 Tool Calls

- **bash_read-file**

---

## 👤 Step 35: User Turn



---

## 🤖 Step 36: LLM Turn

### 💭 Thinking Process

<details>
<summary>Click to expand reasoning</summary>

The implementation is complete. Let me summarize what was done:

1. Added `initialDiscoveryDone :: MVar ()` field to the `Toolbox` type with documentation
2. Added `waitForInitialDiscovery :: Toolbox -> IO ()` function that blocks until initial discovery completes
3. Added `waitForInitialDiscoveryTimeout :: Int -> Toolbox -> IO Bool` function that waits with a timeout (returns True if discovery completed, False if timeout was reached)
4. Modified `initializeMcpToolbox` to create the `MVar` and pass it to the tracer
5. Modified `storeToolsInDiscoveredValues` to accept the `MVar ()` and populate it when the first `ToolsRefreshed` event is received
6. The MVar population is idempotent (using `tryTakeMVar >> putMVar`) so subsequent `ToolsRefreshed` events don't cause errors
7. Added explicit export list with proper documentation sections
8. All code compiles and tests pass

The solution addresses the race condition mentioned in the problem by providing a way to wait for initial tool discovery before using the toolbox.
</details>

### 💬 Response

The implementation is complete. Here's a summary of the changes made to `src/System/Agents/Tools/McpToolbox.hs`:

## Summary of Changes

### 1. Added `initialDiscoveryDone` field to `Toolbox`
```haskell
data Toolbox = Toolbox
    { ...
    , initialDiscoveryDone :: MVar ()  -- ^ MVar filled when initial tool discovery completes
    }
```

### 2. Added synchronization functions
- **`waitForInitialDiscovery :: Toolbox -> IO ()`** - Blocks until the first `ToolsRefreshed` event is received from the MCP server
- **`waitForInitialDiscoveryTimeout :: Int -> Toolbox -> IO Bool`** - Same as above but with a timeout (microseconds). Returns `True` if discovery completed, `False` if timeout reached

### 3. Modified `storeToolsInDiscoveredValues` tracer
- Now accepts an `MVar ()` parameter
- Populates the MVar when the first `ToolsRefreshed` event is received
- Uses idempotent pattern `tryTakeMVar >> putMVar` to safely handle multiple refresh events

### 4. Added explicit export list with documentation sections
- Types section: `ToolDescription`, `Trace`, `Toolbox`
- Initialization: `initializeMcpToolbox`
- Synchronization: `waitForInitialDiscovery`, `waitForInitialDiscoveryTimeout`

### Key Design Decisions

1. **Idempotent signaling**: Using `tryTakeMVar >> putMVar` ensures that even if multiple `ToolsRefreshed` events occur, the MVar is only filled once and subsequent events don't block or error

2. **Timeout support**: The `waitForInitialDiscoveryTimeout` function addresses the tradeoff mentioned in the issue about preventing indefinite blocking

3. **Edge case handling**: If the MCP server disconnects or fails before sending `ToolsRefreshed`, the MVar will remain empty and callers using the timeout variant can detect this
