diff --git a/components/reasoning-workspace.jsx b/components/reasoning-workspace.jsx
index e240e9c..15d0b20 100644
--- a/components/reasoning-workspace.jsx
+++ b/components/reasoning-workspace.jsx
@@ -170,10 +170,35 @@ function FocusedQuestionBody({
   focusedContributions,
   currentFindings,
   onUpdateFindingDisposition,
+  onUpdateFindingProposition,
 }) {
   const hasContent = focused?.question?.trim() || formulationStep === "active" || processingStep === "active" || focused?.error;
   const hasResult = Boolean(focused?.result);
 
+  // ── Local correction state (FQB-owned, not propagated upward) ─
+  const [editingFindingId, setEditingFindingId] = useState(null);
+  const [draft, setDraft] = useState("");
+
+  function startEditing(id, proposition) {
+    setEditingFindingId(id);
+    setDraft(proposition ?? "");
+  }
+
+  function cancelEditing() {
+    setEditingFindingId(null);
+    setDraft("");
+  }
+
+  function saveEditing() {
+    const trimmed = (draft ?? "").trim();
+    if (!trimmed || !editingFindingId) {
+      cancelEditing();
+      return;
+    }
+    onUpdateFindingProposition?.(editingFindingId, trimmed);
+    cancelEditing();
+  }
+
   return (
     <>
       {isFocused && hasContent && (
@@ -206,14 +231,40 @@ function FocusedQuestionBody({
                 <div><h3 className="mb-1 text-[11px] font-semibold tracking-widest uppercase text-gray-500">What this tells us</h3><ul className="list-disc pl-5 space-y-2">{(currentFindings?.length ? currentFindings : (focused.result.observations || [])).map((item, i) => {
                   const isFinding = typeof item === "object" && item !== null && "id" in item;
                   const disposition = isFinding ? item.userDisposition : null;
+                  const isEditing = isFinding && editingFindingId === item.id;
+                  if (!isFinding) {
+                    return (
+                      <li key={i} className="text-sm leading-relaxed text-gray-700">{item}</li>
+                    );
+                  }
+                  if (isEditing) {
+                    return (
+                      <li key={i} className="text-sm leading-relaxed text-gray-700 flex items-start gap-2">
+                        <textarea
+                          value={draft}
+                          onChange={(e) => setDraft(e.target.value)}
+                          rows={2}
+                          data-testid="proposition-editor"
+                          className="flex-1 rounded border border-blue-300 bg-blue-50/40 px-2 py-1 text-sm focus:border-blue-400 focus:outline-none focus:ring-1 focus:ring-blue-300"
+                        />
+                        <div className="flex gap-1 shrink-0 mt-[2px]">
+                          <button onClick={(e) => { e.stopPropagation(); saveEditing(); }} data-testid="proposition-save" className="text-[10px] font-medium text-blue-600 underline shrink-0 hover:text-blue-700">Save</button>
+                          <button onClick={(e) => { e.stopPropagation(); cancelEditing(); }} data-testid="proposition-cancel" className="text-[10px] font-medium text-gray-400 underline shrink-0 hover:text-gray-500">Cancel</button>
+                        </div>
+                      </li>
+                    );
+                  }
                   return (
                     <li key={i} className="text-sm leading-relaxed text-gray-700 flex items-start gap-2">
-                      <span className="flex-1">{currentFindings?.length ? item.proposition : item}</span>
+                      <span className="flex-1">{item.proposition}</span>
+                      {onUpdateFindingProposition && (
+                        <button onClick={(e) => { e.stopPropagation(); startEditing(item.id, item.proposition); }} data-testid={`not-quite-${item.id}`} className="mt-[2px] text-[10px] font-medium text-amber-500 underline shrink-0 hover:text-amber-600">Not quite</button>
+                      )}
                       {isFinding && onUpdateFindingDisposition && (
                         disposition === "not_relevant" ? (
-                          <button onClick={(e) => { e.stopPropagation(); onUpdateFindingDisposition(item.id, null); }} className="mt-[2px] text-[10px] font-medium text-teal-600 underline shrink-0 hover:text-teal-700" title="Restore to understanding">restore</button>
+                          <button onClick={(e) => { e.stopPropagation(); onUpdateFindingDisposition(item.id, null); }} data-testid={`restore-${item.id}`} className="mt-[2px] text-[10px] font-medium text-teal-600 underline shrink-0 hover:text-teal-700" title="Restore to understanding">restore</button>
                         ) : (
-                          <button onClick={(e) => { e.stopPropagation(); onUpdateFindingDisposition(item.id, "not_relevant"); }} className="mt-[2px] text-[10px] font-medium text-gray-400 underline shrink-0 hover:text-red-500" title="Remove from understanding">not relevant</button>
+                          <button onClick={(e) => { e.stopPropagation(); onUpdateFindingDisposition(item.id, "not_relevant"); }} data-testid={`not-relevant-${item.id}`} className="mt-[2px] text-[10px] font-medium text-gray-400 underline shrink-0 hover:text-red-500" title="Remove from understanding">not relevant</button>
                         )
                       )}
                     </li>
@@ -1041,6 +1092,7 @@ function FocusedInvestigationWorkspace({
   focusedContributions,
   currentFindings,
   onUpdateFindingDisposition,
+  onUpdateFindingProposition,
 }) {
   const hasResult = Boolean(focused?.result);
 
@@ -1070,6 +1122,7 @@ function FocusedInvestigationWorkspace({
             focusedContributions={hasResult ? [] : (focusedContributions || [])}
             currentFindings={currentFindings || []}
             onUpdateFindingDisposition={onUpdateFindingDisposition}
+            onUpdateFindingProposition={onUpdateFindingProposition}
           />
         </div>
 
@@ -1091,6 +1144,7 @@ function OpenQuestionsPanel({
   setFocusedPresentationItemId, setFocusedAnswer, focusedAnswer, setDoneForNowIds,
   setFollowUpQuestion, focusedContributions, focusedInvestigations, setIsFocusedWorkspaceOpen,
   onUpdateFindingDisposition,
+  onUpdateFindingProposition,
 }) {
   const openNodes = (graph?.nodes || []).filter(
     (n) => n.kind === "unknown" && n.status !== "resolved" && !doneForNowIds.includes(n.id),
@@ -1169,6 +1223,7 @@ function OpenQuestionsPanel({
                   setFollowUpQuestion={setFollowUpQuestion}
                   focusedContributions={focusedContributions}
                   onUpdateFindingDisposition={onUpdateFindingDisposition}
+                  onUpdateFindingProposition={onUpdateFindingProposition}
                 />
 
                 {/* Thread contributions for this node */}
@@ -1212,6 +1267,7 @@ export default function ReasoningWorkspace({
   onFocusedContribution,
   findings,
   onUpdateFindingDisposition,
+  onUpdateFindingProposition,
 }) {
   const [investigationHistory, setInvestigationHistory] = useState([]);
   const turnCounter = useRef(0);
@@ -1816,6 +1872,7 @@ export default function ReasoningWorkspace({
                                 focusedContributions={focusedContributions}
                                 currentFindings={currentFindings || []}
                                 onUpdateFindingDisposition={onUpdateFindingDisposition}
+                                onUpdateFindingProposition={onUpdateFindingProposition}
                               />
                             );
                           })()}
@@ -1891,6 +1948,7 @@ export default function ReasoningWorkspace({
                     focusedContributions={focusedContributions}
                     focusedInvestigations={focusedInvestigations}
                     setIsFocusedWorkspaceOpen={setIsFocusedWorkspaceOpen}
+                    onUpdateFindingProposition={onUpdateFindingProposition}
                   />
                 )}
 
@@ -2066,6 +2124,7 @@ export default function ReasoningWorkspace({
                         focusedContributions={focusedContributions}
                         currentFindings={currentFindings || []}
                         onUpdateFindingDisposition={onUpdateFindingDisposition}
+                        onUpdateFindingProposition={onUpdateFindingProposition}
                       />
                       {/* Workspace navigation — hidden during formulation/loading states */}
                       {formulationStep !== "active" && (
diff --git a/components/scenario-form.jsx b/components/scenario-form.jsx
index 00d8a94..379a7f1 100644
--- a/components/scenario-form.jsx
+++ b/components/scenario-form.jsx
@@ -276,6 +276,16 @@ export default function ScenarioForm() {
     );
   }
 
+  function updateFindingProposition(findingId, newProposition) {
+    setFindings((prev) =>
+      prev.map((f) =>
+        f.id === findingId
+          ? { ...f, proposition: newProposition, userDisposition: null }
+          : f,
+      ),
+    );
+  }
+
   function appendFocusedContribution(contribution) {
     // Derive a single stored contribution object and use it for BOTH
     // contribution storage AND Finding derivation so the same identity
@@ -630,6 +640,7 @@ export default function ScenarioForm() {
                 onFocusedContribution={appendFocusedContribution}
                 findings={findings}
                 onUpdateFindingDisposition={updateFindingDisposition}
+                onUpdateFindingProposition={updateFindingProposition}
                 onRestart={() => {
                   clearSession();
                   setStatus("idle");
diff --git a/tests/v03-reasoning.test.js b/tests/v03-reasoning.test.js
index 62fd897..42825e4 100644
--- a/tests/v03-reasoning.test.js
+++ b/tests/v03-reasoning.test.js
@@ -812,3 +812,222 @@ describe("applyFindingsToSummary — disposition-aware", () => {
     expect(content).toContain("notQuiteTexts");
   });
 });
+
+// ── updateFindingProposition mutation seam (ScenarioForm) ───
+
+describe("updateFindingProposition — ScenarioForm mutation seam", () => {
+  function simulateUpdateFindingProposition(findings, findingId, newProposition) {
+    return findings.map((f) =>
+      f.id === findingId
+        ? { ...f, proposition: newProposition, userDisposition: null }
+        : f,
+    );
+  }
+
+  const baseFindings = [
+    {
+      id: "f1",
+      proposition: "Original text A",
+      userDisposition: null,
+      sourceObservation: "obs-001",
+      contributionId: "contrib-0001",
+      originatingTargetNodeId: "node-A",
+      createdAt: "2024-01-01T00:00:00Z",
+      status: "confirmed",
+    },
+    {
+      id: "f2",
+      proposition: "Original text B",
+      userDisposition: null,
+      sourceObservation: "obs-002",
+      contributionId: "contrib-0001",
+      originatingTargetNodeId: "node-B",
+      createdAt: "2024-01-01T00:01:00Z",
+      status: "confirmed",
+    },
+  ];
+
+  it("target finding.id is unchanged", () => {
+    const result = simulateUpdateFindingProposition(baseFindings, "f1", "New text A");
+    expect(result[0].id).toBe("f1");
+  });
+
+  it("target proposition changes to new value", () => {
+    const result = simulateUpdateFindingProposition(baseFindings, "f1", "Corrected text A");
+    expect(result[0].proposition).toBe("Corrected text A");
+  });
+
+  it("target userDisposition resets to null", () => {
+    const findingsWithNull = baseFindings.map((f) => f.id === "f2" ? { ...f, userDisposition: "not_relevant" } : f);
+    const result = simulateUpdateFindingProposition(findingsWithNull, "f2", "Corrected text B");
+    expect(result[1].userDisposition).toBeNull();
+  });
+
+  it("sourceObservation remains unchanged on target", () => {
+    const result = simulateUpdateFindingProposition(baseFindings, "f1", "New text A");
+    expect(result[0].sourceObservation).toBe("obs-001");
+  });
+
+  it("contributionId remains unchanged on target", () => {
+    const result = simulateUpdateFindingProposition(baseFindings, "f1", "New text A");
+    expect(result[0].contributionId).toBe("contrib-0001");
+  });
+
+  it("finding.id remains unchanged on target (reconfirmed)", () => {
+    const result = simulateUpdateFindingProposition(baseFindings, "f1", "New text A");
+    expect(result[0].id).toBe("f1");
+  });
+
+  it("another Finding (non-target) remains the exact existing object", () => {
+    const before = baseFindings.find((f) => f.id === "f2");
+    const result = simulateUpdateFindingProposition(baseFindings, "f1", "New text A");
+    const after = result.find((f) => f.id === "f2");
+    expect(after).toBe(before); // same object reference
+  });
+
+  it("no Finding is added or removed — count unchanged", () => {
+    const beforeCount = baseFindings.length;
+    const result = simulateUpdateFindingProposition(baseFindings, "f1", "New text A");
+    expect(result.length).toBe(beforeCount);
+  });
+});
+
+// ── onUpdateFindingProposition prop chain verification ───────────
+
+describe("onUpdateFindingProposition — prop chain verification", () => {
+  it("ScenarioForm exposes updateFindingProposition callback with correct arity", async () => {
+    const testFindings = [{ id: "f1", proposition: "P", userDisposition: null }];
+
+    const updateFindingProposition = (findingId, newProposition) => {
+      return testFindings.map((f) =>
+        f.id === findingId ? { ...f, proposition: newProposition, userDisposition: null } : f,
+      );
+    };
+
+    const updated = updateFindingProposition("f1", "Corrected");
+    expect(updated[0].proposition).toBe("Corrected");
+    expect(updated[0].userDisposition).toBeNull();
+  });
+
+  it("ReasoningWorkspace accepts onUpdateFindingProposition as prop", async () => {
+    const path = join(dirname(fileURLToPath(import.meta.url)), "..", "components", "reasoning-workspace.jsx");
+    const content = await fs.readFile(path, "utf-8");
+
+    expect(content).toContain("onUpdateFindingProposition");
+  });
+
+  it("ReasoningWorkspace passes onUpdateFindingProposition to FocusedInvestigationWorkspace", async () => {
+    const path = join(dirname(fileURLToPath(import.meta.url)), "..", "components", "reasoning-workspace.jsx");
+    const content = await fs.readFile(path, "utf-8");
+
+    const fiwsCall = content.match(/<FocusedInvestigationWorkspace[\s\S]*?\/>/g);
+    expect(fiwsCall).not.toBeNull();
+    expect(fiwsCall[0]).toContain("onUpdateFindingProposition");
+  });
+
+  it("ScenarioForm passes onUpdateFindingProposition to ReasoningWorkspace", async () => {
+    const path = join(dirname(fileURLToPath(import.meta.url)), "..", "components", "scenario-form.jsx");
+    const content = await fs.readFile(path, "utf-8");
+    expect(content).toContain("onUpdateFindingProposition={updateFindingProposition}");
+  });
+
+  it("no correction state introduced in ReasoningWorkspace — only FQB owns editingFindingId + draft", async () => {
+    const rwPath = join(dirname(fileURLToPath(import.meta.url)), "..", "components", "reasoning-workspace.jsx");
+    const rwContent = await fs.readFile(rwPath, "utf-8");
+
+    // ReasoningWorkspace should NOT declare editingFindingId or draft as its own state
+    // (they are only declared inside FocusedQuestionBody)
+    const reasonFuncMatch = rwContent.match(/export default function ReasoningWorkspace\([\s\S]*?return \(/);
+    expect(reasonFuncMatch).not.toBeNull();
+    const funcBody = reasonFuncMatch[0];
+    expect(funcBody).not.toMatch(/editingFindingId/);
+    expect(funcBody).not.toMatch(/setEditingFindingId/);
+  });
+
+  it("Not quite invokes correction for exact Finding.id", async () => {
+    // Simulate: user clicks "Not quite" → startEditing(id, proposition)
+    let state = { editingFindingId: null, draft: "" };
+    const startEditing = (id, proposition) => {
+      state.editingFindingId = id;
+      state.draft = proposition ?? "";
+    };
+
+    startEditing("f1", "Original text A");
+
+    expect(state.editingFindingId).toBe("f1");
+    expect(state.draft).toBe("Original text A");
+  });
+
+  it("cancel does not invoke canonical mutation", async () => {
+    let mutations = [];
+    const originalMutation = (id, val) => { mutations.push({ id, val }); };
+
+    let state = { editingFindingId: "f1", draft: "changed" };
+
+    // Simulate cancel — clears state without calling mutation
+    state.editingFindingId = null;
+    state.draft = "";
+
+    expect(mutations.length).toBe(0);
+    expect(state.editingFindingId).toBeNull();
+    expect(state.draft).toBe("");
+  });
+
+  it("valid save invokes proposition mutation with exact Finding.id + trimmed text", () => {
+    let mutations = [];
+    const mockMutation = (id, val) => { mutations.push({ id, val }); };
+
+    let state = { editingFindingId: "f1", draft: "  corrected text  " };
+
+    const saveEditing = () => {
+      const trimmed = (state.draft ?? "").trim();
+      if (!trimmed || !state.editingFindingId) { return; }
+      mockMutation(state.editingFindingId, trimmed);
+      state.editingFindingId = null;
+      state.draft = "";
+    };
+
+    saveEditing();
+
+    expect(mutations).toEqual([{ id: "f1", val: "corrected text" }]);
+    expect(state.editingFindingId).toBeNull();
+  });
+
+  it("whitespace-only save does not invoke mutation", () => {
+    let mutations = [];
+    const mockMutation = (id, val) => { mutations.push({ id, val }); };
+
+    let state = { editingFindingId: "f1", draft: "   \n\t  " };
+
+    const saveEditing = () => {
+      const trimmed = (state.draft ?? "").trim();
+      if (!trimmed || !state.editingFindingId) { return; }
+      mockMutation(state.editingFindingId, trimmed);
+      state.editingFindingId = null;
+      state.draft = "";
+    };
+
+    saveEditing();
+
+    expect(mutations.length).toBe(0);
+    expect(state.editingFindingId).not.toBeNull(); // state preserved when no-op
+  });
+
+  it("Not quite and Not relevant coexist on same Finding", async () => {
+    const path = join(dirname(fileURLToPath(import.meta.url)), "..", "components", "reasoning-workspace.jsx");
+    const content = await fs.readFile(path, "utf-8");
+
+    // Both buttons should appear in the same rendering block for findings
+    const findingLiBlock = content.match(/<ul className="list-disc pl-5 space-y-2"[\s\S]*?<\/ul>/g);
+    expect(findingLiBlock).not.toBeNull();
+    expect(findingLiBlock[0]).toContain("Not quite");
+    expect(findingLiBlock[0]).toContain("not relevant");
+  });
+
+  it("restore button still present after Not quite introduced", async () => {
+    const path = join(dirname(fileURLToPath(import.meta.url)), "..", "components", "reasoning-workspace.jsx");
+    const content = await fs.readFile(path, "utf-8");
+
+    expect(content).toContain(">restore<");
+  });
+});