diff --git a/changelog.d/fixes/8946-no-tool-output.md b/changelog.d/fixes/8946-no-tool-output.md
new file mode 100644
index 0000000000..9dd6ed3369
--- /dev/null
+++ b/changelog.d/fixes/8946-no-tool-output.md
@@ -0,0 +1 @@
+- fix(compression): drop orphan custom_tool_call/local_shell_call/apply_patch_call on compaction restore (#8946)
diff --git a/open-sse/services/compression/bodyAdapter.ts b/open-sse/services/compression/bodyAdapter.ts
index 64edaca84e..467575349f 100644
--- a/open-sse/services/compression/bodyAdapter.ts
+++ b/open-sse/services/compression/bodyAdapter.ts
@@ -400,13 +400,24 @@ export function adaptBodyForCompression(
       });
 
       const cleanedInput = nextInput.filter((item) => {
-        if (!isRecord(item) || item.type !== "function_call") return true;
+        if (!isRecord(item)) return true;
+        const t = item.type;
+        if (
+          t !== "function_call" &&
+          t !== "custom_tool_call" &&
+          t !== "local_shell_call" &&
+          t !== "apply_patch_call"
+        ) {
+          return true;
+        }
         if (typeof item.call_id !== "string" || item.call_id.length === 0) return true;
         const hadMappedOutput = mappings.some((mapping) => {
           const original = mapping.item;
           return (
             (original.type === "function_call_output" ||
-              original.type === "custom_tool_call_output") &&
+              original.type === "custom_tool_call_output" ||
+              original.type === "local_shell_call_output" ||
+              original.type === "apply_patch_call_output") &&
             original.call_id === item.call_id
           );
         });
diff --git a/tests/unit/compression/responses-orphan-tool-call.test.ts b/tests/unit/compression/responses-orphan-tool-call.test.ts
new file mode 100644
index 0000000000..d0091f142a
--- /dev/null
+++ b/tests/unit/compression/responses-orphan-tool-call.test.ts
@@ -0,0 +1,144 @@
+/**
+ * #8946 — "No tool output found" for custom tool calls (Codex desktop)
+ *
+ * Compaction Layer-3 purify_history drops oldest messages. The restore path's
+ * orphan-call cleanup only removed function_call items whose outputs vanished.
+ * custom_tool_call / local_shell_call / apply_patch_call were left orphaned,
+ * causing a 400 from the upstream Responses API.
+ *
+ * These tests pin the fix: the compaction restore co-drops any tool-call item
+ * whose output was removed, mirroring the existing function_call logic.
+ */
+import test from "node:test";
+import assert from "node:assert/strict";
+import { adaptBodyForCompression } from "../../../open-sse/services/compression/bodyAdapter.ts";
+import { compressContext, estimateTokens } from "../../../open-sse/services/contextManager.ts";
+
+function isRecord(v: unknown): v is Record<string, unknown> {
+  return !!v && typeof v === "object" && !Array.isArray(v);
+}
+
+const TOOL_CALL_TYPES = new Set([
+  "function_call",
+  "custom_tool_call",
+  "local_shell_call",
+  "apply_patch_call",
+]);
+
+const OUTPUT_TYPES = new Set([
+  "function_call_output",
+  "custom_tool_call_output",
+  "local_shell_call_output",
+  "apply_patch_call_output",
+]);
+
+/**
+ * Scan restored input for orphaned tool calls (a call item whose matching
+ * output is absent). Returns an array of descriptive strings, empty = clean.
+ */
+function findOrphanToolCalls(input: unknown[]): string[] {
+  const orphans: string[] = [];
+  for (const item of input) {
+    if (!isRecord(item)) continue;
+    if (!TOOL_CALL_TYPES.has(String(item.type))) continue;
+    const callId = typeof item.call_id === "string" && item.call_id.length > 0 ? item.call_id : "";
+    if (!callId) continue;
+
+    const hasMatchingOutput = input.some(
+      (other) => isRecord(other) && OUTPUT_TYPES.has(String(other.type)) && other.call_id === callId
+    );
+    if (!hasMatchingOutput) {
+      orphans.push(`${String(item.type)} ${callId}`);
+    }
+  }
+  return orphans.sort();
+}
+
+/**
+ * Build a Responses body with N tool-using turns.
+ * Each turn: tool_call + tool_call_output + assistant message + user message.
+ * The user messages carry substantial text to survive Layer-1 trim_tools and
+ * force Layer-3 purify_history to engage.
+ */
+function buildToolTurnBody(
+  numTurns: number,
+  outputText: string,
+  userText: string
+): { input: Record<string, unknown>[] } {
+  const input: Record<string, unknown>[] = [];
+  for (let i = 0; i < numTurns; i++) {
+    // Each turn has one of each tool call type, cycling through them
+    const toolTypes: Array<{
+      callType: string;
+      outputType: string;
+      name: string;
+    }> = [
+      { callType: "custom_tool_call", outputType: "custom_tool_call_output", name: "my_tool" },
+      { callType: "function_call", outputType: "function_call_output", name: "run_command" },
+      { callType: "local_shell_call", outputType: "local_shell_call_output", name: "run_shell" },
+      { callType: "apply_patch_call", outputType: "apply_patch_call_output", name: "apply_diff" },
+    ];
+    const t = toolTypes[i % toolTypes.length];
+    const callId = `${t.callType}-${i}`;
+
+    input.push({ type: t.callType, call_id: callId, name: t.name, arguments: "{}" });
+    input.push({ type: t.outputType, call_id: callId, output: outputText });
+    input.push({
+      type: "message",
+      role: "assistant",
+      content: [{ type: "output_text", text: `response ${i}` }],
+    });
+    input.push({
+      type: "message",
+      role: "user",
+      content: [{ type: "input_text", text: `${userText} turn ${i}` }],
+    });
+  }
+  return { input };
+}
+
+test("#8946: compaction drops orphan custom_tool_call / local_shell_call / apply_patch_call with vanished outputs", () => {
+  // Build many turns: user messages carry enough text to survive Layer-1
+  // trim_tools (which only trims role:"tool" content) so the aggregate
+  // token count still exceeds the compact target after trimming, forcing
+  // Layer-3 purify_history to engage.
+  const outputText = "result: ok";
+  const userText = "x".repeat(3_000); // ~750 tokens each
+  const body = buildToolTurnBody(8, outputText, userText);
+
+  const adapter = adaptBodyForCompression(body);
+  assert.equal(adapter.adapted, true);
+
+  // Calculate before so we can set a target that forces Layer-3.
+  const before = estimateTokens(adapter.body.messages as Record<string, unknown>[]);
+  const target = Math.max(5_000, Math.floor(before * 0.5));
+
+  const result = compressContext(adapter.body as Record<string, unknown>, {
+    provider: "codex",
+    model: "gpt-5.6-terra",
+    maxTokens: target,
+    reserveTokens: 0,
+  });
+
+  assert.equal(
+    result.compressed,
+    true,
+    `compression should engage (before=${before}, target=${target}, stats=${JSON.stringify(result.stats)})`
+  );
+
+  const restored = adapter.restore(result.body as Record<string, unknown>, {
+    dropMissingMappedItems: true,
+  });
+
+  const input = Array.isArray(restored.input) ? restored.input : [];
+  const orphans = findOrphanToolCalls(input);
+
+  // Before the fix: custom_tool_call, local_shell_call, apply_patch_call
+  // orphans survive. After the fix: none survive.
+  assert.equal(
+    orphans.length,
+    0,
+    `restored input contains orphaned tool calls whose outputs were dropped: ${JSON.stringify(orphans)} ` +
+      `(restored input length: ${input.length})`
+  );
+});