Build out all 27 modules + capstone (#1)

Co-authored-by: claude <claude@jpaul.io>
Co-committed-by: claude <claude@jpaul.io>

modules/27-evals/lab/candidates/current_model/tasks.py

@@ -0,0 +1,43 @@
+"""Candidate output: the CURRENT model/prompt.
+
+This is what your agent produced for the task "implement pending_count() so it
+returns the number of tasks that are not done." It's correct. Replace this whole
+directory with your own agent's real output when you run the lab for real.
+"""
+
+from dataclasses import dataclass, field
+
+
+@dataclass
+class Task:
+    title: str
+    done: bool = False
+
+
+@dataclass
+class TaskList:
+    tasks: list[Task] = field(default_factory=list)
+
+    def add(self, title: str) -> Task:
+        task = Task(title=title)
+        self.tasks.append(task)
+        return task
+
+    def complete(self, index: int) -> None:
+        self.tasks[index].done = True
+
+    def pending(self) -> list[Task]:
+        return [t for t in self.tasks if not t.done]
+
+    def pending_count(self) -> int:
+        # Correct: count only the tasks that aren't done.
+        return len(self.pending())
+
+    def render(self) -> str:
+        if not self.tasks:
+            return "(no tasks yet)"
+        lines = []
+        for i, task in enumerate(self.tasks):
+            box = "[x]" if task.done else "[ ]"
+            lines.append(f"{i}. {box} {task.title}")
+        return "\n".join(lines)

modules/27-evals/lab/candidates/swapped_model/tasks.py

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+"""Candidate output: a SWAPPED model/prompt.
+
+Same task, different model (or a tweaked prompt). This output "looks right" and
+passes a casual manual check — adding three tasks and calling count returns 3.
+But pending_count() returns the total number of tasks, not the number of
+*pending* ones, so it's wrong the moment anything is marked done.
+
+Nobody would notice this by skimming. The eval set notices it instantly. That's
+the regression eval catching an unsafe swap — exactly the scenario this module
+exists for. Replace this with your own swapped-model output when you run it for
+real; you may get lucky and have it pass, or you may catch a regression like
+this one.
+"""
+
+from dataclasses import dataclass, field
+
+
+@dataclass
+class Task:
+    title: str
+    done: bool = False
+
+
+@dataclass
+class TaskList:
+    tasks: list[Task] = field(default_factory=list)
+
+    def add(self, title: str) -> Task:
+        task = Task(title=title)
+        self.tasks.append(task)
+        return task
+
+    def complete(self, index: int) -> None:
+        self.tasks[index].done = True
+
+    def pending(self) -> list[Task]:
+        return [t for t in self.tasks if not t.done]
+
+    def pending_count(self) -> int:
+        # WRONG, but plausibly so: counts every task, not just pending ones.
+        return len(self.tasks)
+
+    def render(self) -> str:
+        if not self.tasks:
+            return "(no tasks yet)"
+        lines = []
+        for i, task in enumerate(self.tasks):
+            box = "[x]" if task.done else "[ ]"
+            lines.append(f"{i}. {box} {task.title}")
+        return "\n".join(lines)