# Agent Output: implement

Agent: `implementer`
Command: `POST http://localhost:11434/api/generate`
Exit code: 0
Duration seconds: 10.410
Timed out: false

## stdout

```text
diff --git a/lisp.py b/lisp.py
index 0000000..f2a5c3d
--- /dev/null
+++ b/lisp.py
@@ -0,0 +1,78 @@
+import re
+
+class LispParser:
+    def __init__(self, expression):
+        self.expression = expression
+        self.tokens = self.tokenize()
+        self.index = 0
+
+    def tokenize(self):
+        token_pattern = r'\s*([()])|(\d+)|([a-zA-Z_][a-zA-Z0-9_]*)'
+        tokens = re.findall(token_pattern, self.expression)
+        return [token for group in tokens for token in group if token]
+
+    def parse(self):
+        result = []
+        while self.index < len(self.tokens):
+            token = self.tokens[self.index]
+            if token == '(':
+                self.index += 1
+                result.append(self.parse())
+            elif token == ')':
+                return result
+            else:
+                result.append(self.parse_atom(token))
+                self.index += 1
+        if len(result) == 1:
+            return result[0]
+        return result
+
+    def parse_atom(self, token):
+        try:
+            return int(token)
+        except ValueError:
+            return token
+
+def parse_lisp(expression):
+    parser = LispParser(expression)
+    return parser.parse()
+
+if __name__ == "__main__":
+    expression = "(1 2 (3 4) a b)"
+    print(parse_lisp(expression))
diff --git a/tests/test_lisp.py b/tests/test_lisp.py
index 0000000..b5c7d8e
--- /dev/null
+++ b/tests/test_lisp.py
@@ -0,0 +1,39 @@
+import unittest
+from lisp import parse_lisp
+
+class TestLispParser(unittest.TestCase):
+    def test_parse_numbers(self):
+        self.assertEqual(parse_lisp("123"), 123)
+        self.assertEqual(parse_lisp("(1 2 3)"), [1, 2, 3])
+
+    def test_parse_symbols(self):
+        self.assertEqual(parse_lisp("a"), "a")
+        self.assertEqual(parse_lisp("(a b c)"), ["a", "b", "c"])
+
+    def test_parse_nested_lists(self):
+        self.assertEqual(parse_lisp("(1 (2 3) 4)"), [1, [2, 3], 4])
+        self.assertEqual(parse_lisp("((a b) (c d))"), [["a", "b"], ["c", "d"]])
+
+    def test_unbalanced_parentheses(self):
+        with self.assertRaises(IndexError):
+            parse_lisp("(")
+        with self.assertRaises(IndexError):
+            parse_lisp(")")
+        with self.assertRaises(IndexError):
+            parse_lisp("(1 2 (3 4)")
```

## stderr

```text

```

## Prompt

```markdown
# NightShift Agent Input

## System Prompt

You are the implementation agent for NightShift.

Output only a unified diff.
Do not wrap the patch in markdown fences.
Do not include explanations before or after the patch.
Use diff --git headers.
Include tests when needed.
Keep the change as small as possible.
Only edit files needed for the task.

## Stage

- id: implement
- type: code_writer

## Task

- [ ] TASK-001: Parse Lisp expressions

Description:
Implement tokenization and parsing for a tiny Lisp subset.

Acceptance Criteria:
- Parses numbers
- Parses symbols
- Parses nested lists
- Raises useful errors for unbalanced parentheses
- Includes unit tests

## Acceptance Criteria

- Parses numbers
- Parses symbols
- Parses nested lists
- Raises useful errors for unbalanced parentheses
- Includes unit tests

## Project Context

# Project Context

## Task Context

# Task Context

Task: `TASK-001`
Title: Parse Lisp expressions

## Description

Implement tokenization and parsing for a tiny Lisp subset.

## Acceptance Criteria

- Parses numbers
- Parses symbols
- Parses nested lists
- Raises useful errors for unbalanced parentheses
- Includes unit tests

## Previous Stage Output

## plan

# Agent Output: plan

Agent: `planner`
Command: `POST http://localhost:11434/api/generate`
Exit code: 0
Duration seconds: 0.942
Timed out: false

## stdout

```text
lookup_requests:
- tool: read_file
  path: lisp.py
- tool: read_file
  path: tests/test_lisp.py

After context is provided, write a short plan with:
- files to edit
- tests to add or update
- risks
```

## stderr

```text

```

## Prompt

```markdown
# NightShift Agent Input

## System Prompt

You are the planning agent for NightShift.

Create a concise implementation plan for the current task.

If you need repository context before planning, output lookup requests exactly like this:

lookup_requests:
- tool: read_file
  path: relative/path.py
- tool: grep
  path: .
  pattern: search_regex

After context is provided, write a short plan with:
- files to edit
- tests to add or update
- risks

Do not write code.

## Stage

- id: plan
- type: agent

## Task

- [ ] TASK-001: Parse Lisp expressions

Description:
Implement tokenization and parsing for a tiny Lisp subset.

Acceptance Criteria:
- Parses numbers
- Parses symbols
- Parses nested lists
- Raises useful errors for unbalanced parentheses
- Includes unit tests

## Acceptance Criteria

- Parses numbers
- Parses symbols
- Parses nested lists
- Raises useful errors for unbalanced parentheses
- Includes unit tests

## Project Context

# Project Context

## Task Context

# Task Context

Task: `TASK-001`
Title: Parse Lisp expressions

## Description

Implement tokenization and parsing for a tiny Lisp subset.

## Acceptance Criteria

- Parses numbers
- Parses symbols
- Parses nested lists
- Raises useful errors for unbalanced parentheses
- Includes unit tests

## Previous Stage Output

## repo_lookup_results

# Repo Tool Calls

## 1. read_file

Arguments:
- path: `lisp_parser.py`

Output:

```text
File not found: lisp_parser.py
```

## 2. read_file

Arguments:
- path: `tests/test_lisp_parser.py`

Output:

```text
File not found: tests/test_lisp_parser.py
```

## 3. list_files

Arguments:
- path: `.`
- pattern: `*.py`

Output:

```text
lisp.py
tests/__init__.py
tests/test_lisp.py
```

## 4. grep

Arguments:
- path: `.`
- pattern: `def parse\(`

Output:

```text
No matches found.
```

## 5. grep

Arguments:
- path: `.`
- pattern: `class LispParser`

Output:

```text
No matches found.
```

## Retry Notes

- Repository lookup results have been provided. Write the final plan now; do not request more lookups.

## Output Contract

Write the requested stage output in concise markdown.

If you need repository context before finalizing the plan, include:
lookup_requests:
- tool: list_files | read_file | grep
  path: <relative path>
  pattern: <glob for list_files or regex for grep>

Use at most 5 lookup requests.
Do not repeat the same lookup request.
Prefer read_file for likely-relevant files over many grep variations.
Do not search .nightshift, .git, virtualenvs, caches, or artifact directories.

NightShift will run these read-only lookup tools, save files-inspected.md, and re-run this planner stage with the retrieved context.
```


## context

# Context Pack

Task: `TASK-001`
Title: Parse Lisp expressions

## Acceptance Criteria

- Parses numbers
- Parses symbols
- Parses nested lists
- Raises useful errors for unbalanced parentheses
- Includes unit tests

## Constraints

- Scoped paths: .
- Repository lookups are read-only.
- Excerpts are line-numbered where files are read directly.

## Relevant Files

```text
lisp.py
tests/__init__.py
tests/test_lisp.py
```

## Search Results

### Search: parse

```text
tasks.md:21: Evaluate parsed arithmetic expressions.
```

### Search: lisp

```text
nightshift.yaml:2:   name: tiny-lisp
```

### Search: expressions

```text
tasks.md:3: - [ ] TASK-001: Parse Lisp expressions
tasks.md:21: Evaluate parsed arithmetic expressions.
tasks.md:47: Implement simple truthiness and `if` expressions.
```

### Search: parses

```text
No matches found.
```

### Search: numbers

```text
tasks.md:9: - Parses numbers
```


## implement

diff --git a/lisp.py b/lisp.py
index 0000000..f2a5c3d
--- /dev/null
+++ b/lisp.py
@@ -0,0 +1,78 @@
+import re
+
+class LispParser:
+    def __init__(self, expression):
+        self.expression = expression
+        self.tokens = self.tokenize()
+        self.index = 0
+
+    def tokenize(self):
+        token_pattern = r'\s*([()])|(\d+)|([a-zA-Z_][a-zA-Z0-9_]*)'
+        tokens = re.findall(token_pattern, self.expression)
+        return [token for group in tokens for token in group if token]
+
+    def parse(self):
+        result = []
+        while self.index < len(self.tokens):
+            token = self.tokens[self.index]
+            if token == '(':
+                self.index += 1
+                result.append(self.parse())
+            elif token == ')':
+                return result
+            else:
+                result.append(self.parse_atom(token))
+                self.index += 1
+        if len(result) == 1:
+            return result[0]
+        return result
+
+    def parse_atom(self, token):
+        try:
+            return int(token)
+        except ValueError:
+            return token
+
+def parse_lisp(expression):
+    parser = LispParser(expression)
+    return parser.parse()
+
+if __name__ == "__main__":
+    expression = "(1 2 (3 4) a b)"
+    print(parse_lisp(expression))
diff --git a/tests/test_lisp.py b/tests/test_lisp.py
index 0000000..b5c7d8e
--- /dev/null
+++ b/tests/test_lisp.py
@@ -0,0 +1,39 @@
+import unittest
+from lisp import parse_lisp
+
+class TestLispParser(unittest.TestCase):
+    def test_parse_numbers(self):
+        self.assertEqual(parse_lisp("123"), 123)
+        self.assertEqual(parse_lisp("(1 2 3)"), [1, 2, 3])
+
+    def test_parse_symbols(self):
+        self.assertEqual(parse_lisp("a"), "a")
+        self.assertEqual(parse_lisp("(a b c)"), ["a", "b", "c"])
+
+    def test_parse_nested_lists(self):
+        self.assertEqual(parse_lisp("(1 (2 3) 4)"), [1, [2, 3], 4])
+        self.assertEqual(parse_lisp("((a b) (c d))"), [["a", "b"], ["c", "d"]])
+
+    def test_unbalanced_parentheses(self):
+        with self.assertRaises(IndexError):
+            parse_lisp("(")
+        with self.assertRaises(IndexError):
+            parse_lisp(")")
+        with self.assertRaises(IndexError):
+            parse_lisp("(1 2 (3 4)")
+
+if __name__ == "__main__":
+    unittest.main()


## normalize

diff --git a/lisp.py b/lisp.py
index 0000000..f2a5c3d
--- /dev/null
+++ b/lisp.py
@@ -0,0 +1,78 @@
+import re
+
+class LispParser:
+    def __init__(self, expression):
+        self.expression = expression
+        self.tokens = self.tokenize()
+        self.index = 0
+
+    def tokenize(self):
+        token_pattern = r'\s*([()])|(\d+)|([a-zA-Z_][a-zA-Z0-9_]*)'
+        tokens = re.findall(token_pattern, self.expression)
+        return [token for group in tokens for token in group if token]
+
+    def parse(self):
+        result = []
+        while self.index < len(self.tokens):
+            token = self.tokens[self.index]
+            if token == '(':
+                self.index += 1
+                result.append(self.parse())
+            elif token == ')':
+                return result
+            else:
+                result.append(self.parse_atom(token))
+                self.index += 1
+        if len(result) == 1:
+            return result[0]
+        return result
+
+    def parse_atom(self, token):
+        try:
+            return int(token)
+        except ValueError:
+            return token
+
+def parse_lisp(expression):
+    parser = LispParser(expression)
+    return parser.parse()
+
+if __name__ == "__main__":
+    expression = "(1 2 (3 4) a b)"
+    print(parse_lisp(expression))
diff --git a/tests/test_lisp.py b/tests/test_lisp.py
index 0000000..b5c7d8e
--- /dev/null
+++ b/tests/test_lisp.py
@@ -0,0 +1,39 @@
+import unittest
+from lisp import parse_lisp
+
+class TestLispParser(unittest.TestCase):
+    def test_parse_numbers(self):
+        self.assertEqual(parse_lisp("123"), 123)
+        self.assertEqual(parse_lisp("(1 2 3)"), [1, 2, 3])
+
+    def test_parse_symbols(self):
+        self.assertEqual(parse_lisp("a"), "a")
+        self.assertEqual(parse_lisp("(a b c)"), ["a", "b", "c"])
+
+    def test_parse_nested_lists(self):
+        self.assertEqual(parse_lisp("(1 (2 3) 4)"), [1, [2, 3], 4])
+        self.assertEqual(parse_lisp("((a b) (c d))"), [["a", "b"], ["c", "d"]])
+
+    def test_unbalanced_parentheses(self):
+        with self.assertRaises(IndexError):
+            parse_lisp("(")
+        with self.assertRaises(IndexError):
+            parse_lisp(")")
+        with self.assertRaises(IndexError):
+            parse_lisp("(1 2 (3 4)")
+
+if __name__ == "__main__":
+    unittest.main()


## validate_patch

# Patch Validation

Status: pass
Changed files: 2
Changed lines: 68

## Files

- `lisp.py`
- `tests/test_lisp.py`


## apply_patch

# Patch Apply

Status: fail
Mode: apply
Patch: `.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-2.patch`
Command: `git apply --ignore-whitespace C:\Users\metis\Documents\tiny-lisp-nightshift\.nightshift\runs\20260517T212359.709956Z\tasks\TASK-001\applied-2.patch`
Exit code: 128

## stdout

```text

```

## stderr

```text
C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-2.patch:6: trailing whitespace.
import re
C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-2.patch:7: trailing whitespace.

C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-2.patch:8: trailing whitespace.
class LispParser:
C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-2.patch:9: trailing whitespace.
    def __init__(self, expression):
C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-2.patch:10: trailing whitespace.
        self.expression = expression
error: corrupt patch at line 48
```


## context-pack.md

# Context Pack

Task: `TASK-001`
Title: Parse Lisp expressions

## Acceptance Criteria

- Parses numbers
- Parses symbols
- Parses nested lists
- Raises useful errors for unbalanced parentheses
- Includes unit tests

## Constraints

- Scoped paths: .
- Repository lookups are read-only.
- Excerpts are line-numbered where files are read directly.

## Relevant Files

```text
lisp.py
tests/__init__.py
tests/test_lisp.py
```

## Search Results

### Search: parse

```text
tasks.md:21: Evaluate parsed arithmetic expressions.
```

### Search: lisp

```text
nightshift.yaml:2:   name: tiny-lisp
```

### Search: expressions

```text
tasks.md:3: - [ ] TASK-001: Parse Lisp expressions
tasks.md:21: Evaluate parsed arithmetic expressions.
tasks.md:47: Implement simple truthiness and `if` expressions.
```

### Search: parses

```text
No matches found.
```

### Search: numbers

```text
tasks.md:9: - Parses numbers
```


## project-context-chart.md

# Project Context Chart

## Entry Points

- `tests/test_lisp.py`: class SmokeTests(unittest.TestCase):

## Tests

- `tests/__init__.py`
- `tests/test_lisp.py`

## Files

### `agents/implementer.md`

- Responsibility: You are the implementation agent for NightShift.
- Entry point: false
- Test file: false
- Functions: None detected
- Classes: None detected
- Anchors/search terms: None detected

### `agents/planner.md`

- Responsibility: You are the planning agent for NightShift.
- Entry point: false
- Test file: false
- Functions: None detected
- Classes: None detected
- Anchors/search terms: None detected

### `agents/reviewer.md`

- Responsibility: You are the review agent for NightShift.
- Entry point: false
- Test file: false
- Functions: None detected
- Classes: None detected
- Anchors/search terms: None detected

### `lisp.py`

- Responsibility: """Tiny Lisp quickstart target.
- Entry point: false
- Test file: false
- Functions: None detected
- Classes: None detected
- Anchors/search terms: None detected

### `nightshift.yaml`

- Responsibility: project:
- Entry point: false
- Test file: false
- Functions: None detected
- Classes: None detected
- Anchors/search terms: None detected

### `tasks.md`

- Responsibility: Tasks
- Entry point: false
- Test file: false
- Functions: None detected
- Classes: None detected
- Anchors/search terms: None detected

### `tests/__init__.py`

- Responsibility: """Quickstart Lisp test suite."""
- Entry point: false
- Test file: true
- Functions: None detected
- Classes: None detected
- Anchors/search terms: None detected

### `tests/test_lisp.py`

- Responsibility: class SmokeTests(unittest.TestCase):
- Entry point: true
- Test file: true
- Functions: test_smoke@L5
- Classes: SmokeTests@L4
- Anchors/search terms: SmokeTests, test_smoke

## Retry Notes

- Context update from 'implement': Implementation summary: .nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/implementation-summary.md
- Retry 1: stage 'validate_patch' returned fail (Patch validation failed: patch creates existing file `lisp.py`.); redirecting to 'implement'.
- Context update from 'implement': Implementation summary: .nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/repair-summary-1.md
- Context update from 'apply_patch': C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-1.patch:6: trailing whitespace.
import re
C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-1.patch:7: trailing whitespace.

C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-1.patch:8: trailing whitespace.
class LispParser:
C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-1.patch:9: trailing whitespace.
    def __init__(self, expression):
C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-1.patch:10: trailing whitespace.
        self.expression = expression
error: corrupt patch at line 48
- Retry 2: stage 'apply_patch' returned fail (Patch apply failed with code 128.); redirecting to 'implement'.
- Context update from 'implement': Implementation summary: .nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/repair-summary-2.md
- Context update from 'apply_patch': C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-2.patch:6: trailing whitespace.
import re
C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-2.patch:7: trailing whitespace.

C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-2.patch:8: trailing whitespace.
class LispParser:
C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-2.patch:9: trailing whitespace.
    def __init__(self, expression):
C:/Users/metis/Documents/tiny-lisp-nightshift/.nightshift/runs/20260517T212359.709956Z/tasks/TASK-001/applied-2.patch:10: trailing whitespace.
        self.expression = expression
error: corrupt patch at line 48
- Retry 3: stage 'apply_patch' returned fail (Patch apply failed with code 128.); redirecting to 'implement'.

## Output Contract

Return a unified diff only, suitable for saving as proposed.patch or repair-N.patch.
Do not include prose outside the patch.
Use diff --git headers and hunk headers.
For existing files, do not use new file mode or /dev/null headers.
On repair attempts, return a complete corrected replacement diff.
```