diff --git a/src/hide-consumed.ts b/src/hide-consumed.ts
index 2456ddb..1d75626 100644
--- a/src/hide-consumed.ts
+++ b/src/hide-consumed.ts
@@ -19,28 +19,92 @@ function rangeKey(startRef: string, endRef: string): string {
     return `${startRef}::${endRef}`;
 }
 
-function rewriteCompressText(text: string | undefined, liveKeys: Set<string>): string | null {
+// Adapters (pi) persist the rendered ref tag in front of the tool-call text,
+// so the JSON args no longer start at index 0. Locate the first "{" instead of
+// parsing the raw text — the prefix is preserved on output.
+function parseCallText(text: string | undefined): { prefix: string; obj: Record<string, unknown>; content: unknown[]; contentWasString: boolean } | null {
+    const raw = text ?? "";
+    const start = raw.indexOf("{");
+    if (start < 0) return null;
     let parsed: unknown;
     try {
-        parsed = JSON.parse(text ?? "");
+        parsed = JSON.parse(raw.slice(start));
     } catch {
         return null;
     }
     if (!parsed || typeof parsed !== "object") return null;
-    const obj = parsed as { content?: unknown };
-    const content = obj.content;
-    if (!Array.isArray(content) || content.length === 0) return null;
+    const obj = parsed as Record<string, unknown>;
+    let content: unknown[] | null = null;
+    let contentWasString = false;
+    if (Array.isArray(obj.content)) {
+        content = obj.content;
+    } else if (typeof obj.content === "string") {
+        // Non-strict-tool providers (qwen etc.) sometimes stringify the content
+        // array inside the JSON args; the compress tool accepts it, so the
+        // rewrite must too. Measured: ALL 52 calls in the billion-context-pi
+        // #336 storm session used this form (#230).
+        contentWasString = true;
+        try {
+            const inner: unknown = JSON.parse(obj.content);
+            if (Array.isArray(inner)) content = inner;
+        } catch {
+            content = null;
+        }
+    }
+    if (!content || content.length === 0) return null;
+    return { prefix: raw.slice(0, start), obj, content, contentWasString };
+}
+
+function rewriteCompressText(text: string | undefined, liveKeys: Set<string>): string | null {
+    const parsed = parseCallText(text);
+    if (!parsed) return null;
+    const { prefix, obj, content, contentWasString } = parsed;
 
     const kept = content.filter((entry): entry is Record<string, unknown> => {
         if (!entry || typeof entry !== "object") return false;
-        const s = typeof entry.startId === "string" ? entry.startId : typeof entry.messageId === "string" ? entry.messageId : "";
-        const e = typeof entry.endId === "string" ? entry.endId : typeof entry.messageId === "string" ? entry.messageId : "";
-        return liveKeys.has(rangeKey(s, e));
+        const e = entry as Record<string, unknown>;
+        const s = typeof e.startId === "string" ? e.startId : typeof e.messageId === "string" ? e.messageId : "";
+        const end = typeof e.endId === "string" ? e.endId : typeof e.messageId === "string" ? e.messageId : "";
+        return liveKeys.has(rangeKey(s, end));
     });
 
-    if (kept.length === content.length || kept.length === 0) return null;
+    if (kept.length === 0) return null;
 
-    return JSON.stringify({ ...obj, content: kept });
+    return prefix + serializeCompacted(obj, kept, contentWasString).text;
+}
+
+// Live compress-call args duplicate every range's full summary text while the
+// rendered acp_summary message already carries it — on long sessions the
+// duplication alone measured ~22K tokens (billion-context-pi #336). Keep a
+// leading stub for recall; the block remains the durable record.
+const SUMMARY_STUB_CHARS = 200;
+
+function compactEntry(entry: unknown): unknown {
+    if (!entry || typeof entry !== "object") return entry;
+    const e = entry as Record<string, unknown>;
+    if (typeof e.summary !== "string" || e.summary.length <= SUMMARY_STUB_CHARS) return entry;
+    return { ...e, summary: `${e.summary.slice(0, SUMMARY_STUB_CHARS - 1)}…` };
+}
+
+function serializeCompacted(obj: Record<string, unknown>, content: unknown[], contentWasString: boolean): { text: string; changed: boolean } {
+    let changed = false;
+    const compacted = content.map((entry) => {
+        const out = compactEntry(entry);
+        if (out !== entry) changed = true;
+        return out;
+    });
+    // Preserve the original shape: a stringified content array stays a string
+    // so downstream text comparisons and replays are unaffected.
+    const outContent = contentWasString ? JSON.stringify(compacted) : compacted;
+    return { text: JSON.stringify({ ...obj, content: outContent }), changed };
+}
+
+function compactCompressText(text: string | undefined): string | null {
+    const parsed = parseCallText(text);
+    if (!parsed) return null;
+    const { prefix, obj, content, contentWasString } = parsed;
+    const { text: out, changed } = serializeCompacted(obj, content, contentWasString);
+    return changed ? prefix + out : null;
 }
 
 export function hideConsumedCompressCalls(
@@ -124,6 +188,11 @@ export function hideConsumedCompressCalls(
                     continue;
                 }
             }
+            const compacted = compactCompressText(message.text);
+            if (compacted !== null) {
+                result.push({ ...message, text: compacted });
+                continue;
+            }
         }
         result.push(message);
     }
diff --git a/tests/hide-consumed-stub.test.ts b/tests/hide-consumed-stub.test.ts
new file mode 100644
index 0000000..2b233e2
--- /dev/null
+++ b/tests/hide-consumed-stub.test.ts
@@ -0,0 +1,167 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { hideConsumedCompressCalls } from "../src/hide-consumed.js";
+import { renderVisibleRefs } from "../src/render-refs.js";
+import { createInitialState } from "../src/state.js";
+import type { CompressionBlock, CompressionState, CoreMessage } from "../src/types.js";
+
+function block(overrides: Partial<CompressionBlock>): CompressionBlock {
+    return {
+        blockId: "b0",
+        runId: "r0",
+        tier: 1,
+        summary: "summary",
+        directMessageIds: [],
+        effectiveMessageIds: [],
+        directBlockIds: [],
+        createdAt: 1000,
+        survivedCount: 0,
+        generation: "young",
+        active: true,
+        ...overrides,
+    };
+}
+
+function callWith(text: string, toolCallId = "call1"): CoreMessage {
+    return { id: "mc1", role: "assistant", contentType: "tool-call", toolName: "compress", toolCallId, text };
+}
+
+function liveState(summary: string, startRef: string, endRef: string): CompressionState {
+    const state = createInitialState();
+    state.blocks.push(block({ blockId: "b1", compressCallId: "call1", summary, startRef, endRef }));
+    return state;
+}
+
+interface StubEntry {
+    startId?: string;
+    summary?: string;
+    topic?: string;
+}
+
+function parsedContent(text: string | undefined): StubEntry[] {
+    return (JSON.parse(text ?? "") as { content: StubEntry[] }).content;
+}
+
+test("fully-live compress call args get their long summaries stubbed", () => {
+    const longSummary = "x".repeat(5000);
+    const callText = JSON.stringify({
+        content: [{ startId: "m00001", endId: "m00050", topic: "T", summary: longSummary }],
+    });
+    const state = liveState(longSummary, "m00001", "m00050");
+
+    const { messages } = hideConsumedCompressCalls(state, [callWith(callText)]);
+
+    assert.equal(messages.length, 1);
+    const content = parsedContent(messages[0]!.text);
+    assert.equal(content.length, 1);
+    assert.equal(content[0]!.summary!.length, 200);
+    assert.ok(content[0]!.summary!.endsWith("…"));
+    assert.ok(content[0]!.summary!.startsWith("xxxx"));
+    assert.equal(content[0]!.topic, "T");
+    assert.equal(content[0]!.startId, "m00001");
+});
+
+test("short summaries are left byte-identical; kept orphans with long summaries are stubbed", () => {
+    const shortText = JSON.stringify({
+        content: [{ startId: "m00001", endId: "m00050", summary: "short" }],
+    });
+    const state = liveState("short", "m00001", "m00050");
+
+    const { messages } = hideConsumedCompressCalls(state, [callWith(shortText)]);
+    assert.equal(messages[0]!.text, shortText);
+
+    const orphanText = JSON.stringify({
+        content: [{ startId: "m00001", endId: "m00050", summary: "y".repeat(4000) }],
+    });
+    const { messages: orphanOut } = hideConsumedCompressCalls(createInitialState(), [callWith(orphanText, "orphan")]);
+    assert.equal(orphanOut.length, 1);
+    assert.equal(parsedContent(orphanOut[0]!.text)[0]!.summary!.length, 200);
+});
+
+test("tag-prefixed compress call text is still parsed and stubbed (ref tag precedes the JSON)", () => {
+    const longSummary = "z".repeat(3000);
+    const state = liveState(longSummary, "m00001", "m00050");
+    state.messageRefs.byRaw["mc1"] = "m00010";
+    state.messageRefs.byRef["m00010"] = "mc1";
+    const callText = JSON.stringify({
+        content: [{ startId: "m00001", endId: "m00050", summary: longSummary }],
+    });
+    const tagged = renderVisibleRefs([callWith(callText)], state)[0]!;
+    assert.ok(tagged.text!.startsWith("<acp "));
+
+    const { messages } = hideConsumedCompressCalls(state, [tagged]);
+    const text = messages[0]!.text!;
+    assert.ok(text.startsWith("<acp "));
+    assert.ok(text.includes("m00010"));
+    const content = JSON.parse(text.slice(text.indexOf("{"))) as { content: { summary: string }[] };
+    assert.equal(content.content[0]!.summary.length, 200);
+});
+
+test("tag-prefixed mixed call: consumed sibling entry is still dropped", () => {
+    const state: CompressionState = {
+        ...createInitialState(),
+        blocks: [
+            block({ blockId: "b5", compressCallId: "call-batch", active: true, startRef: "m5", endRef: "m6" }),
+            block({ blockId: "b8", compressCallId: "call-batch", active: false, startRef: "m8", endRef: "m9" }),
+        ],
+    };
+    state.messageRefs.byRaw["mc"] = "m00010";
+    state.messageRefs.byRef["m00010"] = "mc";
+    const call: CoreMessage = {
+        id: "mc",
+        role: "assistant",
+        contentType: "tool-call",
+        toolName: "compress",
+        toolCallId: "call-batch",
+        text: JSON.stringify({
+            content: [
+                { startId: "m5", endId: "m6", summary: "live entry summary" },
+                { startId: "m8", endId: "m9", summary: "c".repeat(300) },
+            ],
+        }),
+    };
+    const tagged = renderVisibleRefs([call], state)[0]!;
+
+    const { messages } = hideConsumedCompressCalls(state, [tagged]);
+    const kept = messages.find((m) => m.toolCallId === "call-batch")!;
+    const text = kept.text!;
+    assert.ok(text.startsWith("<acp "));
+    const content = JSON.parse(text.slice(text.indexOf("{"))) as { content: { startId: string; summary: string }[] };
+    assert.equal(content.content.length, 1);
+    assert.equal(content.content[0]!.startId, "m5");
+    assert.equal(content.content[0]!.summary, "live entry summary");
+});
+
+test("parseCallText handles stringified content arrays and preserves the string shape (#230)", () => {
+    const state: CompressionState = {
+        ...createInitialState(),
+        blocks: [
+            block({ blockId: "b1", compressCallId: "call-str", active: true, startRef: "m1", endRef: "m2" }),
+            block({ blockId: "b2", compressCallId: "call-str", active: false, startRef: "m3", endRef: "m4" }),
+        ],
+    };
+    const inner = JSON.stringify([
+        { startId: "m1", endId: "m2", summary: "x".repeat(300) },
+        { startId: "m3", endId: "m4", summary: "y".repeat(300) },
+    ]);
+    const messages: CoreMessage[] = [
+        {
+            id: "m5",
+            role: "assistant",
+            contentType: "tool-call",
+            toolName: "compress",
+            toolCallId: "call-str",
+            text: JSON.stringify({ content: inner }),
+        },
+    ];
+    const result = hideConsumedCompressCalls(state, messages);
+    const kept = result.messages.find((m) => m.toolCallId === "call-str");
+    assert.ok(kept, "live call kept");
+    const parsed = JSON.parse(kept!.text!.replace(/^[^{]*/, "")) as { content: unknown };
+    assert.equal(typeof parsed.content, "string", "string shape preserved");
+    const entries = JSON.parse(parsed.content as string) as { startId: string; summary: string }[];
+    assert.equal(entries.length, 1);
+    assert.equal(entries[0]!.startId, "m1");
+    assert.ok(entries[0]!.summary.length <= 200, "summary stubbed");
+    assert.ok(entries[0]!.summary.endsWith("…"));
+});