diff --git a/docs/writeup/data/teacher_ablation.csv b/docs/writeup/data/teacher_ablation.csv
new file mode 100644
index 0000000..1a36c22
--- /dev/null
+++ b/docs/writeup/data/teacher_ablation.csv
@@ -0,0 +1,23 @@
+step,arm,teacher_schedule,lr,deploy_hack,deploy_solve,job
+0,vanilla,off@40,3e-3,0.000,0.359,87
+20,vanilla,off@40,3e-3,0.141,0.438,87
+40,vanilla,off@40,3e-3,0.359,0.359,87
+60,vanilla,off@40,3e-3,0.438,0.562,87
+80,vanilla,off@40,3e-3,0.453,0.531,87
+100,vanilla,off@40,3e-3,0.469,0.531,87
+120,vanilla,off@40,3e-3,0.500,0.500,87
+140,vanilla,off@40,3e-3,0.516,0.422,87
+160,vanilla,off@40,3e-3,0.578,0.359,87
+180,vanilla,off@40,3e-3,0.469,0.469,87
+199,vanilla,off@40,3e-3,0.484,0.453,87
+0,vanilla,on,1e-3,0.000,0.328,97
+20,vanilla,on,1e-3,0.000,0.484,97
+40,vanilla,on,1e-3,0.172,0.500,97
+60,vanilla,on,1e-3,0.250,0.547,97
+80,vanilla,on,1e-3,0.219,0.500,97
+100,vanilla,on,1e-3,0.281,0.469,97
+120,vanilla,on,1e-3,0.328,0.406,97
+140,vanilla,on,1e-3,0.281,0.453,97
+160,vanilla,on,1e-3,0.328,0.438,97
+180,vanilla,on,1e-3,0.391,0.500,97
+199,vanilla,on,1e-3,0.344,0.500,97
diff --git a/docs/writeup/figs/plot_teacher_ablation.py b/docs/writeup/figs/plot_teacher_ablation.py
new file mode 100644
index 0000000..94a4564
--- /dev/null
+++ b/docs/writeup/figs/plot_teacher_ablation.py
@@ -0,0 +1,51 @@
+"""Teacher-ablation appendix figure: does cutting the teacher at step 40 stop
+the vanilla student from hacking? Reads data/teacher_ablation.csv, writes
+figs/teacher_ablation.{png,pdf}.
+
+Claim under test: once the student produces its own hacks, the cached teacher is
+no longer load-bearing -- removing it at step 40 does not bend the deploy-hack
+trajectory down. The post-cut segment of the off@40 curve keeps rising, so the
+teacher is a seeder, not the driver.
+
+Caveat baked into the legend: the off@40 run (job 87) used the default fast LR
+(3e-3) while the teacher-on reference (job 97) used the gentler 1e-3 that survives
+200 steps without the over-optimization collapse. The within-run post-cut rise is
+the confound-free part of the evidence; the matched-LR pair is job 124 (queued).
+
+FIXME: jobs 87/97 are the closest match but differ in LR. When job 124 (gentle
+vanilla teacher-off@40) lands, replace the off@40 rows in teacher_ablation.csv with
+job 124's trajectory (single-variable vs job 97) and drop the LR caveat.
+"""
+from pathlib import Path
+import polars as pl
+import matplotlib.pyplot as plt
+
+HERE = Path(__file__).parent
+df = pl.read_csv(HERE.parent / "data" / "teacher_ablation.csv")
+
+fig, ax = plt.subplots(figsize=(5.0, 3.2))
+
+styles = {
+    "off@40": dict(color="#c1272d", marker="o", label="teacher off @ step 40 (job 87, lr 3e-3)"),
+    "on":     dict(color="#444444", marker="s", label="teacher on throughout (job 97, lr 1e-3)"),
+}
+for sched, sty in styles.items():
+    d = df.filter(pl.col("teacher_schedule") == sched).sort("step")
+    ax.plot(d["step"], d["deploy_hack"], lw=1.6, ms=4, **sty)
+
+# teacher-cut marker for the off@40 arm
+ax.axvline(40, color="#c1272d", ls=":", lw=1.0)
+ax.annotate("teacher removed", xy=(40, 0.04), xytext=(52, 0.04),
+            color="#c1272d", fontsize=8, va="center")
+
+ax.set_xlabel("GRPO step")
+ax.set_ylabel("deploy hack rate (n=64, T=0.7)")
+ax.set_ylim(-0.02, 0.65)
+ax.set_xlim(-3, 203)
+ax.legend(frameon=False, fontsize=8, loc="upper left")
+ax.spines[["top", "right"]].set_visible(False)
+fig.tight_layout()
+
+for ext in ("png", "pdf"):
+    fig.savefig(HERE / f"teacher_ablation.{ext}", dpi=150, bbox_inches="tight")
+print("wrote", HERE / "teacher_ablation.png")
diff --git a/docs/writeup/figs/teacher_ablation.pdf b/docs/writeup/figs/teacher_ablation.pdf
new file mode 100644
index 0000000..5a49bf0
Binary files /dev/null and b/docs/writeup/figs/teacher_ablation.pdf differ
diff --git a/docs/writeup/figs/teacher_ablation.png b/docs/writeup/figs/teacher_ablation.png
new file mode 100644
index 0000000..1f938ca
Binary files /dev/null and b/docs/writeup/figs/teacher_ablation.png differ
diff --git a/docs/writeup/main.tex b/docs/writeup/main.tex
index 7d12c1a..7f9cda8 100644
--- a/docs/writeup/main.tex
+++ b/docs/writeup/main.tex
@@ -597,8 +597,11 @@ Third, the clean control cuts the teacher entirely at step 40 (seed, then pure
 on-policy to 200) for both vanilla and route2. If the teacher were necessary,
 vanilla hacking would decay and route2's suppression would lose its target after
 the cut; if it is an accelerant, vanilla keeps hacking and route2 keeps holding
-deploy hack near zero. \TODO{figure from jobs 93/94 (\texttt{--teacher-off-step=40},
-seed 41); queued.}
+deploy hack near zero. The vanilla half is in
+Appendix~\ref{app:teacher}: removing the teacher at step 40 does not bend the
+deploy-hack curve down -- it keeps climbing on the student's own hacks
+($0.36\to0.58$), so the teacher seeds the behaviour rather than sustaining it.
+The route2 half is job 105 (queued).
 
 \section{Related work}
 % PROVENANCE: differentiators + no-cheat scorecard curated in
@@ -991,6 +994,45 @@ live teacher grad) decays $\sim$0.28$\to$0.07 by step 10 on frozen-V; refresh-2
 holds the second-half cosine $\sim$1.43$\times$ higher. Include the
 \texttt{basis\_overlap\_with\_prev} check for route refresh.}
 
+\section{Teacher-off control: the teacher seeds, it does not sustain}
+\label{app:teacher}
+% PROVENANCE: deploy-hack trajectories parsed from the DEPLOY-eval log lines of
+% pueue jobs 87 (vanilla teacher-off@40, default fast lr 3e-3) and 97 (vanilla
+% teacher-on, gentle lr 1e-3). Data: docs/writeup/data/teacher_ablation.csv;
+% figure regenerated by docs/writeup/figs/plot_teacher_ablation.py.
+% FIXME: jobs 87 and 97 are the closest match available but differ in lr (3e-3 vs
+% 1e-3); swap the teacher-on curve for the lr-matched job 124 (gentle vanilla
+% teacher-off@40) once it lands, re-run plot_teacher_ablation.py, drop the caveat.
+The cached teacher pool ($\sim$12.5\% of each batch) is the obvious confound: maybe
+routing only suppresses a teacher-injected gradient. Figure~\ref{fig:teacher} runs
+the vanilla student with the teacher cut entirely at step 40, then trained pure
+on-policy to 200. If the teacher were the driver, deploy hacking would decay after
+the cut. Instead it keeps climbing on the student's own hacks, from $0.36$ at the
+cut to a $0.58$ peak, ending at $0.48$ -- at or above a run where the teacher stays
+on the whole way. The slope does not break at the cut, so by step 40 the student is
+self-supplying the hack gradient and the teacher is an accelerant, not a
+prerequisite.
+
+The two curves differ in learning rate (the teacher-off run uses the default fast
+$3\mathrm{e}{-3}$; the teacher-on reference uses the gentler $1\mathrm{e}{-3}$ that
+survives 200 steps without the over-optimization collapse of
+Sec.~\ref{app:context}), so their absolute levels are not strictly comparable; the
+confound-free claim is the within-run rise after the cut. A learning-rate-matched
+teacher-off-vs-on pair is job 124 (queued).
+
+\begin{figure}[h]
+  \centering
+  \includegraphics[width=0.7\linewidth,alt={Deploy hack rate vs GRPO step for two
+  vanilla runs. The teacher-off-at-step-40 run keeps rising after the teacher is
+  removed, from 0.36 to a 0.58 peak, ending above the teacher-on run.}]%
+  {figs/teacher_ablation.pdf}
+  \caption{Cutting the teacher at step 40 (dotted line) does not stop vanilla
+  hacking -- the deploy-hack curve keeps climbing on the student's own rollouts.
+  See Appendix text for the learning-rate caveat. Data:
+  \texttt{data/teacher\_ablation.csv}.}
+  \label{fig:teacher}
+\end{figure}
+
 \section{Ablation context (prior fast-preset runs)}
 \label{app:context}
 % PROVENANCE for this whole section: docs/results.md (curated snapshot