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

**🔑 Session ID:** 597aa1ea-3895-49ae-b119-9f269ca7eef1

---

## 📊 Statistics

### Turn Counts

| Metric | Value |
|--------|-------|
| Total Turns | 90 |
| 👤 User Turns | 45 |
| 🤖 LLM Turns | 45 |

### 🔧 Tool Calls

**Total Tool Calls:** 50

`bash_write-file     `   22 ████████████████████████████████████████████████████████████
`bash_read-file      `   18 █████████████████████████████████████████████████
`bash_check-code     `    8 █████████████████████
`bash_grep-files     `    1 ██
`bash_list-files     `    1 ██

### 💾 Byte Usage

`Input     `    474 KiB ████████████████████████████████████████████████████████████
`Output    `      2 KiB 
`Reasoning `      6 KiB 
**Total:** 483 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

# Display byte usage at each step with breakdown by category

Depends-on: #193
Base-branch: gh-194
Final: false

## Overview

Add byte usage tracking and display for each step in a conversation session. This feature will show:
1. **Total byte usage per step**
2. **Breakdown by category**: input, output, reasoning, and tool calls

This helps users understand token/byte consumption patterns and optimize their agent interactions.

## Motivation

- **Cost transparency**: Users need visibility into how much data is being exchanged with LLMs
- **Debugging**: Understanding byte distribution helps identify unexpectedly large payloads
- **Optimization**: Users can identify steps with excessive token usage and optimize prompts
- **Reasoning visibility**: Track how much data is in reasoning/thinking blocks vs actual output

## Data Types to Modify

### 1. Session Types (`src/System/Agents/Session/Types.hs`)

Add a new type to represent byte usage breakdown:

```haskell
-- | Byte usage breakdown for a single step
data StepByteUsage = StepByteUsage
    { stepTotalBytes :: Int
      -- ^ Total bytes for this step
    , stepInputBytes :: Int
      -- ^ Bytes in the input (prompt + context + query)
    , stepOutputBytes :: Int
      -- ^ Bytes in the LLM output response
    , stepReasoningBytes :: Int
      -- ^ Bytes in reasoning/thinking content (if model supports it)
    , stepToolBytes :: Int
      -- ^ Bytes in tool call responses
    } deriving (Show, Eq, Generic)

instance FromJSON StepByteUsage
instance ToJSON StepByteUsage
```

Modify `Turn` to optionally include byte usage:

```haskell
data Turn
  = UserTurn UserTurnContent (Maybe StepByteUsage)
  | LlmTurn LlmTurnContent (Maybe StepByteUsage)
    deriving (Show, Ord, Eq, Generic)
```

### 2. LLM Types (`src/System/Agents/LLMs/OpenAI.hs`)

Add byte counting helpers:

```haskell
-- | Calculate byte size of a JSON Value for tracking purposes
calculatePayloadBytes :: Aeson.Value -> Int

-- | Extend Trace with byte usage info
data Trace
    = CallChatCompletion !Aeson.Value !Int  -- payload + byte count
    | GotChatCompletion !Aeson.Value !Int   -- response + byte count
    | HttpClientTrace !HttpClient.Trace
    deriving (Show)
```

## Implementation Tasks

### Task 1: Add StepByteUsage type and update Turn (depends on #193)

Location: `src/System/Agents/Session/Types.hs`

- Add `StepByteUsage` data type with fields for total, input, output, reasoning, and tool bytes
- Update `Turn` type to include `Maybe StepByteUsage`
- Update JSON instances
- **Breaking change**: This changes the `Turn` constructors

### Task 2: Add byte counting to OpenAI module

Location: `src/System/Agents/LLMs/OpenAI.hs`

- Add `calculatePayloadBytes :: Aeson.Value -> Int` function using `Data.Aeson.encode`
- Modify `callLLMPayload` to:
  - Calculate request payload bytes before sending
  - Calculate response bytes after receiving
  - Return byte counts alongside the response
- Update `Trace` constructors to include byte counts
- Export byte counting utilities

### Task 3: Track bytes in tool execution

Location: `src/System/Agents/Tools/Base.hs` or tool execution context

- Add byte counting for tool responses
- Export utility to calculate tool response size

### Task 4: Integrate byte tracking in Session Step

Location: `src/System/Agents/Session/Step.hs`

- Modify `runStepM` to:
  - Calculate input bytes for user turns (prompt + tools + query + tool responses)
  - Calculate output/reasoning/tool bytes for LLM turns
  - Store `StepByteUsage` when creating each turn
- The step function has access to:
  - For UserTurn: `sPrompt`, `sTools`, `uQuery`, `results` (tool responses)
  - For LlmTurn: `llmRsp` (contains responseText, responseThinking), `llmTool` (tool calls)

### Task 5: Display byte usage in TUI

Location: `src/System/Agents/TUI/Render.hs`

- Modify `render_turn` to display byte usage information:
  - Show total bytes for the step
  - Show breakdown in a compact format (e.g., "in: 1.2KB, out: 0.8KB, reason: 0.5KB, tool: 2.1KB")
- Add new attribute for byte usage text (dimmed/smaller text)
- Consider showing byte breakdown on a second line or as tooltip-style info

Example render output:
```
> System prompt...                    [in: 1.2KB]
< User query here                     [in: 0.1KB]
< LLM response here                   [out: 0.8KB, reason: 0.5KB]
  [tool calls: 2]                     [tool: 2.1KB]
```

### Task 6: Display byte usage in CLI trace output

Location: `src/System/Agents/CLI/TraceUtils.hs`

- Modify `renderConversationAgentTrace` to include byte usage when available
- Show summary in trace output for debugging

### Task 7: Add cumulative session byte usage

Location: `src/System/Agents/Session/Types.hs`, `src/System/Agents/TUI/Render.hs`

- Add helper to calculate total session bytes: `sessionTotalBytes :: Session -> Int`
- Display session total in TUI status bar or session view header

## Tradeoffs

### Performance vs Accuracy
- **Option A**: Count bytes eagerly during step execution (accurate, slight overhead)
- **Option B**: Count lazily when displaying (less overhead, may miss transient data)
- **Recommendation**: Option A - eager counting, as the overhead of `ByteString.length` on JSON is negligible

### Storage vs Completeness
- Storing `Maybe StepByteUsage` allows backward compatibility with sessions that don't have byte data
- Once deployed, all new sessions will have byte data

### Display Verbosity
- Full breakdown may clutter the TUI
- Consider: 
  - Default: Show total only
  - Detailed view: Show full breakdown (toggle with key)
  - Color coding: Different colors for input/output/reasoning/tool

## Dependencies

- Depends on #193 (presumably session tracking infrastructure changes)

## Acceptance Criteria

- [ ] Each `Turn` stores optional `StepByteUsage`
- [ ] `StepByteUsage` tracks: total, input, output, reasoning, tool bytes
- [ ] Byte counts are calculated for LLM requests/responses
- [ ] Byte counts are calculated for tool responses
- [ ] TUI displays byte usage per step (at minimum: total)
- [ ] TUI optionally shows full breakdown (can be toggle or always visible)
- [ ] CLI trace output includes byte usage information
- [ ] Session total byte usage is available and displayed
- [ ] JSON serialization/deserialization works correctly
- [ ] Existing sessions without byte data continue to work (backward compatibility)

## Related Files

- `src/System/Agents/Session/Types.hs` - Core types
- `src/System/Agents/Session/Step.hs` - Step execution
- `src/System/Agents/LLMs/OpenAI.hs` - LLM byte counting
- `src/System/Agents/Tools/Base.hs` - Tool byte counting
- `src/System/Agents/TUI/Render.hs` - TUI display
- `src/System/Agents/TUI/Types.hs` - TUI state (may need new event for byte updates)
- `src/System/Agents/CLI/TraceUtils.hs` - CLI trace display
- `src/System/Agents/Runtime/Trace.hs` - Runtime tracing

---
From #215



### 🛠️ 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 to understand the codebase and then implement the byte usage tracking feature.
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_list-files**

---

## 👤 Step 3: User Turn



---

## 🤖 Step 4: LLM Turn

### 💭 Thinking Process

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

Let me start by examining the key files I need to modify:
1. `src/System/Agents/Session/Types.hs` - For adding StepByteUsage type
2. `src/System/Agents/LLMs/OpenAI.hs` - For byte counting
3. `src/System/Agents/Session/Step.hs` - For integrating byte tracking
4. `src/System/Agents/TUI/Render.hs` - For TUI display
5. `src/System/Agents/Tools/Base.hs` - For tool byte counting
6. `src/System/Agents/CLI/TraceUtils.hs` - For CLI trace output
</details>

### 💬 Response

Let me start by reading the key files to understand the current structure:

### 🔧 Tool Calls

- **bash_read-file**
- **bash_read-file**
- **bash_read-file**

---

## 👤 Step 5: User Turn



---

## 🤖 Step 6: LLM Turn

### 💭 Thinking Process

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

Now let me read the Tools/Base.hs file and TUI Render.hs:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_read-file**
- **bash_read-file**
- **bash_read-file**

---

## 👤 Step 7: User Turn



---

## 🤖 Step 8: LLM Turn

### 💭 Thinking Process

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

Now I need to look at the TUI Types and Runtime/Trace to understand how things are connected:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_read-file**
- **bash_read-file**
- **bash_read-file**

---

## 👤 Step 9: User Turn



---

## 🤖 Step 10: LLM Turn

### 💭 Thinking Process

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

Now I have a good understanding of the codebase. Let me implement the byte usage tracking feature step by step.

The implementation plan:
1. First, I'll modify `src/System/Agents/Session/Types.hs` to add the `StepByteUsage` type and update `Turn` to include optional byte usage.
2. Then update `src/System/Agents/LLMs/OpenAI.hs` to add byte counting and update `Trace`.
3. Update `src/System/Agents/Tools/Base.hs` to add byte counting for tool responses.
4. Update `src/System/Agents/Session/Step.hs` to calculate and store byte usage.
5. Update `src/System/Agents/TUI/Render.hs` to display byte usage.
6. Update `src/System/Agents/CLI/TraceUtils.hs` to include byte usage in trace output.

Let me start with the implementation:
</details>

### 💬 Response

Now I have a good understanding of the codebase. Let me implement the byte usage tracking feature step by step.

## Task 1: Add StepByteUsage type and update Turn

### 🔧 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 update the OpenAI module to add byte counting to the Trace type and add the calculatePayloadBytes function.
</details>

### 💬 Response

## Task 2: Add byte counting to OpenAI module

### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 13: User Turn



---

## 🤖 Step 14: LLM Turn

### 💭 Thinking Process

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

Now I need to update the Tools/Base.hs to add a helper for calculating tool response bytes. Let me also check the Tools/Context.hs to understand the flow better.
</details>

### 💬 Response

## Task 3: Add byte counting for tool responses

### 🔧 Tool Calls

- **bash_read-file**

---

## 👤 Step 15: User Turn



---

## 🤖 Step 16: LLM Turn

### 💭 Thinking Process

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

Now let me update Tools/Base.hs to add a helper for calculating tool response bytes. I need to add a function that can calculate the byte size of a tool response.
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 17: User Turn



---

## 🤖 Step 18: LLM Turn

### 💭 Thinking Process

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

I made an error - I put the import statements at the end of the file instead of at the top. Let me fix that.
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 19: User Turn



---

## 🤖 Step 20: LLM Turn

### 💭 Thinking Process

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

Now let me update the Session/Step.hs to integrate byte tracking. This is the key file where we need to calculate and store byte usage for each turn.
</details>

### 💬 Response

## Task 4: Integrate byte tracking in Session Step

### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 21: User Turn



---

## 🤖 Step 22: LLM Turn

### 💭 Thinking Process

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

I made some errors in the Step.hs file. Let me fix them - I used `calculateLlmTurnUsage` instead of `calculateLlmTurnByteUsage` and forgot to add the calculatePayloadBytes import from the OpenAI module properly. Let me also fix the missing imports.
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 23: User Turn



---

## 🤖 Step 24: LLM Turn

### 💭 Thinking Process

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

Now let me compile to see if there are any errors so far:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_check-code**

---

## 👤 Step 25: User Turn



---

## 🤖 Step 26: LLM Turn

### 💭 Thinking Process

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

The issue is that `StepByteUsage` doesn't have an `Ord` instance, but it's used in `Turn` which derives `Ord`. I need to add `Ord` to the derived instances for `StepByteUsage`.
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 27: User Turn



---

## 🤖 Step 28: LLM Turn

### 💭 Thinking Process

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

Now let me compile again to check for more errors:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_check-code**

---

## 👤 Step 29: User Turn



---

## 🤖 Step 30: LLM Turn

### 💭 Thinking Process

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

I need to fix several files that use the Turn constructors. Let me start with the Session/Edit.hs file:
</details>

### 💬 Response

Let me fix the files that need to be updated for the new Turn constructors:

### 🔧 Tool Calls

- **bash_read-file**

---

## 👤 Step 31: User Turn



---

## 🤖 Step 32: LLM Turn

### 💭 Thinking Process

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

I need to update these files to handle the new Turn constructor with the Maybe StepByteUsage argument. Let me fix them:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 33: User Turn



---

## 🤖 Step 34: LLM Turn

### 💭 Thinking Process

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

Now let me fix the Tools/Base.hs import issue and then the other files.
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 35: User Turn



---

## 🤖 Step 36: LLM Turn

### 💭 Thinking Process

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

Now let me read and fix the SessionPrint/Inject.hs file:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_read-file**

---

## 👤 Step 37: User Turn



---

## 🤖 Step 38: LLM Turn

### 💭 Thinking Process

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

Let me fix the SessionPrint/Inject.hs file to handle the new Turn constructors:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 39: User Turn



---

## 🤖 Step 40: LLM Turn

### 💭 Thinking Process

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

Now let me fix the SessionPrint.hs file:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_read-file**

---

## 👤 Step 41: User Turn



---

## 🤖 Step 42: LLM Turn

### 💭 Thinking Process

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

I need to update this file to handle the new Turn constructor format with Maybe StepByteUsage:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 43: User Turn



---

## 🤖 Step 44: LLM Turn

### 💭 Thinking Process

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

Now let me fix the Session/OpenAI.hs file to handle the new Turn constructor:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_read-file**

---

## 👤 Step 45: User Turn



---

## 🤖 Step 46: LLM Turn

### 💭 Thinking Process

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

I see the issue in Session/OpenAI.hs - the pattern match on `LlmTurn` and `UserTurn` needs to account for the new `Maybe StepByteUsage` field. Let me fix it:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 47: User Turn



---

## 🤖 Step 48: LLM Turn

### 💭 Thinking Process

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

Now let me compile to see if there are more errors:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_check-code**

---

## 👤 Step 49: User Turn



---

## 🤖 Step 50: LLM Turn

### 💭 Thinking Process

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

There are several issues to fix:
1. Need to add TypeApplications to SessionPrint/Inject.hs and SessionPrint.hs
2. Need to fix the Session/Step.hs - issues with CallResult type mismatch and Int64 vs Int 
3. Need to fix TUI/Render.hs to handle the new Turn constructors
4. Need to fix CLI/TraceUtils.hs to handle the new Trace constructors

Let me fix these files one by one:
</details>

### 💬 Response

Let me fix the remaining files. First, let me fix the Session/Step.hs issues:

### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 51: User Turn



---

## 🤖 Step 52: LLM Turn

### 💭 Thinking Process

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

Now let me fix the SessionPrint/Inject.hs file to remove the visible type applications and just use normal show:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 53: User Turn



---

## 🤖 Step 54: LLM Turn

### 💭 Thinking Process

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

Now let me fix the SessionPrint.hs file:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 55: User Turn



---

## 🤖 Step 56: LLM Turn

### 💭 Thinking Process

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

Now let me fix the TUI/Render.hs file to handle the new Turn constructors and also add byte usage display:
</details>

### 💬 Response

## Task 5: Display byte usage in TUI

### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 57: User Turn



---

## 🤖 Step 58: LLM Turn

### 💭 Thinking Process

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

Now let me fix the CLI/TraceUtils.hs file to handle the new Trace constructors:
</details>

### 💬 Response

## Task 6: Display byte usage in CLI trace output

### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 59: User Turn



---

## 🤖 Step 60: LLM Turn

### 💭 Thinking Process

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

Now let me compile again to check if all the issues are fixed:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_check-code**

---

## 👤 Step 61: User Turn



---

## 🤖 Step 62: LLM Turn

### 💭 Thinking Process

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

There are a few issues to fix:
1. `hFill` is not in scope in TUI/Render.hs - I need to import it from Brick or use a different approach
2. `PostgRESTrace` typo in CLI/TraceUtils.hs - should be `PostgRESTTrace`

Let me fix these:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 63: User Turn



---

## 🤖 Step 64: LLM Turn

### 💭 Thinking Process

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

Now let me fix the TUI/Render.hs to use `fill` instead of `hFill` (which doesn't exist in Brick). The `fill` function works for both horizontal and vertical fill:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 65: User Turn



---

## 🤖 Step 66: LLM Turn

### 💭 Thinking Process

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

Now let me compile again:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_check-code**

---

## 👤 Step 67: User Turn



---

## 🤖 Step 68: LLM Turn

### 💭 Thinking Process

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

There are still some test files and the Main.hs that need to be updated. Let me fix the app/Main.hs and test files:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_read-file**

---

## 👤 Step 69: User Turn



---

## 🤖 Step 70: LLM Turn

### 💭 Thinking Process

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

I need to fix the app/Main.hs to handle the new Trace constructors with byte counts. Let me find the relevant line and fix it:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_grep-files**

---

## 👤 Step 71: User Turn



---

## 🤖 Step 72: LLM Turn

### 💭 Thinking Process

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

Let me fix the app/Main.hs to handle the new Trace constructors:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_read-file**

---

## 👤 Step 73: User Turn



---

## 🤖 Step 74: LLM Turn

### 💭 Thinking Process

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

The app/Main.hs looks fine. The issue is around line 1210. Let me look at that specific section:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 75: User Turn



---

## 🤖 Step 76: LLM Turn

### 💭 Thinking Process

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

Now I need to fix the test files. Let me read and fix the SessionEditTests.hs:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_read-file**

---

## 👤 Step 77: User Turn



---

## 🤖 Step 78: LLM Turn

### 💭 Thinking Process

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

I need to fix the SessionEditTests.hs to handle the new Turn constructors with Maybe StepByteUsage. Let me update the test file:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

---

## 👤 Step 79: User Turn



---

## 🤖 Step 80: LLM Turn

### 💭 Thinking Process

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

Now let me compile again to see if all the issues are fixed:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_check-code**

---

## 👤 Step 81: User Turn



---

## 🤖 Step 82: 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 is working:
</details>

### 💬 Response

The code compiles successfully. Let me run the tests to verify everything is working correctly:

### 🔧 Tool Calls

- **bash_check-code**

---

## 👤 Step 83: User Turn



---

## 🤖 Step 84: LLM Turn

### 💭 Thinking Process

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

The test failures are minor formatting issues in the elideDocument function - it's missing a space after `...(` in some places. These are cosmetic issues in the SessionPrint.hs file. Let me fix those:
</details>

### 💬 Response

The test failures are minor formatting issues in the elideDocument function. Let me fix those:

### 🔧 Tool Calls

- **bash_read-file**

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## 👤 Step 85: User Turn



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## 🤖 Step 86: LLM Turn

### 💭 Thinking Process

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

The test failures are about a missing space after `...(` in the elision markers. Looking at the test expectations:
- Expected: `"line1\nline2\n... (1 line elided) ...\nline4\nline5"`
- Got: `"line1\nline2\n...(1 line elided) ...\nline4\nline5"`

The issue is I changed from `... (` to `...(` (removed the space). Let me fix this to maintain the expected format that the tests require:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_write-file**

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## 👤 Step 87: User Turn



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## 🤖 Step 88: LLM Turn

### 💭 Thinking Process

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

Now let me run the tests again to verify all tests pass:
</details>

### 💬 Response



### 🔧 Tool Calls

- **bash_check-code**

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## 👤 Step 89: User Turn



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## 🤖 Step 90: LLM Turn

### 💭 Thinking Process

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

All tests pass now. Let me provide a summary of the changes made to implement the byte usage tracking feature.
</details>

### 💬 Response

All tests pass. Let me provide a summary of the implementation:

## Summary

I have successfully implemented byte usage tracking and display for each step in a conversation session. Here's what was done:

### Files Modified:

1. **`src/System/Agents/Session/Types.hs`**:
   - Added `StepByteUsage` data type with fields for total, input, output, reasoning, and tool bytes
   - Updated `Turn` type to include `Maybe StepByteUsage` for backward compatibility
   - Added helper functions `calculateStepByteUsage` and `sessionTotalBytes`

2. **`src/System/Agents/LLMs/OpenAI.hs`**:
   - Updated `Trace` type to include byte counts: `CallChatCompletion !Aeson.Value !Int` and `GotChatCompletion !Aeson.Value !Int`
   - Added `calculatePayloadBytes` helper function

3. **`src/System/Agents/Tools/Base.hs`**:
   - Added `callResultByteSize` function to calculate byte sizes for tool responses
   - Added `sumToolResponseBytes` helper

4. **`src/System/Agents/Session/Step.hs`**:
   - Modified `runStepM` to calculate and store `StepByteUsage` for each turn
   - Added `calculateUserTurnByteUsage` and `calculateLlmTurnByteUsage` functions

5. **`src/System/Agents/TUI/Render.hs`**:
   - Added byte usage display per turn with breakdown (in: X, out: Y, reason: Z, tool: W)
   - Added session total byte display at the top
   - Added `byteUsageAttr` for styling

6. **`src/System/Agents/CLI/TraceUtils.hs`**:
   - Updated trace output to include byte counts
   - Added `formatBytes` helper for human-readable formatting

7. **`src/System/Agents/Session/Edit.hs`**, **`src/System/Agents/SessionPrint.hs`**, **`src/System/Agents/SessionPrint/Inject.hs`**, **`src/System/Agents/Session/OpenAI.hs`**, **`app/Main.hs`**, **`test/SessionEditTests.hs`**:
   - Updated pattern matches to handle the new `Turn` constructor with `Maybe StepByteUsage`

### Features Implemented:
- ✅ `StepByteUsage` type with total, input, output, reasoning, and tool bytes
- ✅ Byte counting for LLM requests/responses  
- ✅ Byte counting for tool responses
- ✅ TUI displays byte usage per step with breakdown
- ✅ Session total byte usage displayed
- ✅ CLI trace output includes byte usage
- ✅ Backward compatibility via `Maybe StepByteUsage`
- ✅ All 254 tests pass
