diff --git a/docs/.generated/plugin-sdk-api-baseline.sha256 b/docs/.generated/plugin-sdk-api-baseline.sha256
index a104254a0b6..8a712e32512 100644
--- a/docs/.generated/plugin-sdk-api-baseline.sha256
+++ b/docs/.generated/plugin-sdk-api-baseline.sha256
@@ -1,2 +1,2 @@
-f3e0379cbe0e584a8c9658253d4a808356fe80fb5ec775bbee9e968e8d815380  plugin-sdk-api-baseline.json
-601b55acafbd1e00b850c9b0c15d587029050906960071d448d37538b223e226  plugin-sdk-api-baseline.jsonl
+a9501e226bb26befb02072cf5e60c3dc124cbd5dc0b16eb281789d0843f72f71  plugin-sdk-api-baseline.json
+b106090dc12bf7e46beac4ed160f0cff0ef8039291f24172b693e8d8b752d571  plugin-sdk-api-baseline.jsonl
diff --git a/src/channels/progress-draft-compositor.test.ts b/src/channels/progress-draft-compositor.test.ts
new file mode 100644
index 00000000000..aaa42fdf266
--- /dev/null
+++ b/src/channels/progress-draft-compositor.test.ts
@@ -0,0 +1,106 @@
+import { describe, expect, it, vi } from "vitest";
+import { createChannelProgressDraftCompositor } from "./progress-draft-compositor.js";
+
+describe("createChannelProgressDraftCompositor", () => {
+  it("keeps the progress label visible when tool lines are hidden", async () => {
+    const update = vi.fn();
+    const progress = createChannelProgressDraftCompositor({
+      entry: {
+        streaming: { mode: "progress", progress: { label: "Shelling", toolProgress: false } },
+      },
+      mode: "progress",
+      active: true,
+      seed: "test",
+      update,
+    });
+
+    await progress.pushToolProgress("🛠️ Exec", { startImmediately: true });
+
+    expect(update).toHaveBeenCalledWith("Shelling", { flush: true });
+  });
+
+  it("keeps reasoning details hidden when tool progress lines are hidden", async () => {
+    const update = vi.fn();
+    const progress = createChannelProgressDraftCompositor({
+      entry: {
+        streaming: { mode: "progress", progress: { label: "Shelling", toolProgress: false } },
+      },
+      mode: "progress",
+      active: true,
+      seed: "test",
+      update,
+    });
+
+    await progress.pushToolProgress("🛠️ Exec", { startImmediately: true });
+    await progress.pushReasoningProgress("Reading files");
+
+    expect(update).toHaveBeenCalledWith("Shelling", { flush: true });
+    expect(update).not.toHaveBeenCalledWith(expect.stringContaining("Reading"), undefined);
+  });
+
+  it("does not resurrect progress after suppression", async () => {
+    const update = vi.fn();
+    const progress = createChannelProgressDraftCompositor({
+      entry: { streaming: { mode: "progress", progress: { label: "Shelling" } } },
+      mode: "progress",
+      active: true,
+      seed: "test",
+      update,
+    });
+
+    progress.suppress();
+    await progress.pushReasoningProgress("Reading files");
+
+    expect(update).not.toHaveBeenCalled();
+  });
+
+  it("composes reasoning deltas with tool progress", async () => {
+    const update = vi.fn();
+    const progress = createChannelProgressDraftCompositor({
+      entry: { streaming: { mode: "progress", progress: { label: "Shelling" } } },
+      mode: "progress",
+      active: true,
+      seed: "test",
+      update,
+    });
+
+    await progress.pushToolProgress("🛠️ Exec", { startImmediately: true });
+    await progress.pushReasoningProgress("Reading");
+    await progress.pushReasoningProgress(" files");
+
+    expect(update).toHaveBeenLastCalledWith("Shelling\n\n🛠️ Exec\n• _Reading files_", undefined);
+  });
+
+  it("preserves tagged reasoning content without leaking tags", async () => {
+    const update = vi.fn();
+    const progress = createChannelProgressDraftCompositor({
+      entry: { streaming: { mode: "progress", progress: { label: "Shelling" } } },
+      mode: "progress",
+      active: true,
+      seed: "test",
+      update,
+    });
+
+    await progress.pushToolProgress("🛠️ Exec", { startImmediately: true });
+    await progress.pushReasoningProgress("<think>Checking files</think>");
+
+    expect(update).toHaveBeenLastCalledWith("Shelling\n\n🛠️ Exec\n• _Checking files_", undefined);
+  });
+
+  it("replaces repeated formatted reasoning snapshots", async () => {
+    const update = vi.fn();
+    const progress = createChannelProgressDraftCompositor({
+      entry: { streaming: { mode: "progress", progress: { label: "Shelling" } } },
+      mode: "progress",
+      active: true,
+      seed: "test",
+      update,
+    });
+
+    await progress.pushToolProgress("🛠️ Exec", { startImmediately: true });
+    await progress.pushReasoningProgress("Thinking\n\n_Reading_");
+    await progress.pushReasoningProgress("Thinking\n\n_Reading files_");
+
+    expect(update).toHaveBeenLastCalledWith("Shelling\n\n🛠️ Exec\n• _Reading files_", undefined);
+  });
+});
diff --git a/src/channels/progress-draft-compositor.ts b/src/channels/progress-draft-compositor.ts
new file mode 100644
index 00000000000..c9d11ada599
--- /dev/null
+++ b/src/channels/progress-draft-compositor.ts
@@ -0,0 +1,387 @@
+import { formatReasoningMessage } from "../agents/embedded-agent-utils.js";
+import { stripInlineDirectiveTagsForDelivery } from "../utils/directive-tags.js";
+import {
+  createChannelProgressDraftGate,
+  type ChannelProgressDraftLine,
+  formatChannelProgressDraftText,
+  isChannelProgressDraftWorkToolName,
+  mergeChannelProgressDraftLine,
+  normalizeChannelProgressDraftLineIdentity,
+  resolveChannelProgressDraftMaxLineChars,
+  resolveChannelProgressDraftMaxLines,
+  resolveChannelStreamingProgressCommentary,
+  resolveChannelStreamingPreviewToolProgress,
+  resolveChannelStreamingSuppressDefaultToolProgressMessages,
+  type StreamingCompatEntry,
+  type StreamingMode,
+} from "./streaming.js";
+
+export type ChannelProgressDraftMode = StreamingMode;
+
+export type ChannelProgressDraftCompositor = ReturnType<
+  typeof createChannelProgressDraftCompositor
+>;
+type ProgressDraftLine = string | ChannelProgressDraftLine;
+
+export function createChannelProgressDraftCompositor(params: {
+  entry: StreamingCompatEntry | null | undefined;
+  mode: ChannelProgressDraftMode;
+  active: boolean;
+  seed: string;
+  update: (text: string, options?: { flush?: boolean }) => Promise<void> | void;
+  deleteCurrent?: () => Promise<void> | void;
+  tryNativeUpdate?: (text: string) => Promise<boolean> | boolean;
+  formatLine?: (line: string) => string;
+  isEmptyLine?: (line: ProgressDraftLine | undefined) => boolean;
+  shouldStartNow?: (line: ProgressDraftLine | undefined) => boolean;
+}) {
+  const previewToolProgressEnabled =
+    params.active && resolveChannelStreamingPreviewToolProgress(params.entry);
+  const commentaryProgressEnabled =
+    params.active && resolveChannelStreamingProgressCommentary(params.entry);
+  const suppressDefaultToolProgressMessages =
+    params.active &&
+    resolveChannelStreamingSuppressDefaultToolProgressMessages(params.entry, {
+      draftStreamActive: true,
+      previewToolProgressEnabled,
+    });
+  let progressSuppressed = false;
+  let lines: ProgressDraftLine[] = [];
+  let lastRenderedText = "";
+  let reasoningRawText = "";
+  let lastReasoningLine: string | undefined;
+  let finalReplyStarted = false;
+  let finalReplyDelivered = false;
+
+  const formatDraftText = (draftLines = lines, options?: { formatted?: boolean }) =>
+    formatChannelProgressDraftText({
+      entry: params.entry,
+      lines: draftLines,
+      seed: params.seed,
+      formatLine: options?.formatted === false ? undefined : params.formatLine,
+    });
+
+  const clearProgressState = (suppressed: boolean) => {
+    progressSuppressed = suppressed;
+    lines = [];
+    lastRenderedText = "";
+    reasoningRawText = "";
+    lastReasoningLine = undefined;
+  };
+
+  const render = async (options?: { flush?: boolean }): Promise<boolean> => {
+    if (!params.active || params.mode !== "progress") {
+      return false;
+    }
+    const text = formatDraftText();
+    if (!text || text === lastRenderedText) {
+      return false;
+    }
+    lastRenderedText = text;
+    await params.update(text, options);
+    return true;
+  };
+
+  const gate = createChannelProgressDraftGate({
+    onStart: async () => {
+      await render({ flush: true });
+    },
+  });
+
+  const clearLine = async (lineId: string) => {
+    const nextLines = lines.filter(
+      (line) => typeof line !== "object" || line.id?.trim() !== lineId,
+    );
+    if (nextLines.length === lines.length) {
+      return;
+    }
+    lines = nextLines;
+    if (!gate.hasStarted) {
+      return;
+    }
+    const text = formatDraftText();
+    if (text) {
+      await render();
+      return;
+    }
+    lastRenderedText = "";
+    await params.deleteCurrent?.();
+  };
+
+  const noteProgress = async (
+    line?: ProgressDraftLine,
+    options?: { toolName?: string; startImmediately?: boolean },
+  ) => {
+    if (!params.active || finalReplyStarted || finalReplyDelivered) {
+      return false;
+    }
+    if (options?.toolName !== undefined && !isChannelProgressDraftWorkToolName(options.toolName)) {
+      return false;
+    }
+    if (params.isEmptyLine?.(line)) {
+      return false;
+    }
+    const normalized = normalizeChannelProgressDraftLineIdentity(line);
+    if (!normalized || progressSuppressed) {
+      return false;
+    }
+    if (params.mode !== "progress" && !previewToolProgressEnabled) {
+      return false;
+    }
+    const progressLine = typeof line === "object" && line !== undefined ? line : normalized;
+    const shouldStoreLine = previewToolProgressEnabled;
+    const nextLines = shouldStoreLine
+      ? mergeChannelProgressDraftLine(lines, progressLine, {
+          maxLines: resolveChannelProgressDraftMaxLines(params.entry),
+        })
+      : lines;
+    if (shouldStoreLine && nextLines === lines) {
+      return false;
+    }
+    if (shouldStoreLine && params.tryNativeUpdate) {
+      const text = formatDraftText(nextLines, { formatted: false });
+      if (text && (await params.tryNativeUpdate(text))) {
+        lines = nextLines;
+        lastRenderedText = text;
+        return true;
+      }
+    }
+    lines = nextLines;
+    if (params.mode !== "progress") {
+      if (!shouldStoreLine) {
+        return false;
+      }
+      const text = formatDraftText();
+      if (!text || text === lastRenderedText) {
+        return false;
+      }
+      lastRenderedText = text;
+      await params.update(text);
+      return true;
+    }
+    if (options?.startImmediately || params.shouldStartNow?.(line)) {
+      await gate.startNow();
+      return gate.hasStarted ? await render() : false;
+    }
+    const alreadyStarted = gate.hasStarted;
+    const progressActive = await gate.noteWork();
+    if ((alreadyStarted || progressActive) && gate.hasStarted) {
+      return await render();
+    }
+    return false;
+  };
+
+  return {
+    get previewToolProgressEnabled() {
+      return previewToolProgressEnabled;
+    },
+    get commentaryProgressEnabled() {
+      return commentaryProgressEnabled;
+    },
+    get suppressDefaultToolProgressMessages() {
+      return suppressDefaultToolProgressMessages;
+    },
+    get hasStarted() {
+      return gate.hasStarted;
+    },
+    markFinalReplyStarted() {
+      finalReplyStarted = true;
+    },
+    markFinalReplyDelivered() {
+      finalReplyDelivered = true;
+    },
+    reset() {
+      clearProgressState(false);
+    },
+    suppress() {
+      clearProgressState(true);
+    },
+    cancel() {
+      gate.cancel();
+    },
+    start() {
+      return gate.startNow();
+    },
+    pushToolProgress: noteProgress,
+    async pushReasoningProgress(text?: string, options?: { snapshot?: boolean }) {
+      if (
+        !params.active ||
+        params.mode !== "progress" ||
+        !text ||
+        progressSuppressed ||
+        finalReplyDelivered
+      ) {
+        return false;
+      }
+      reasoningRawText = mergeReasoningProgressText(reasoningRawText, text, {
+        snapshot: options?.snapshot === true,
+      });
+      const normalized = normalizeReasoningProgressLine(reasoningRawText);
+      if (!normalized) {
+        return false;
+      }
+      const displayLine = formatReasoningProgressDisplayLine(
+        normalized,
+        resolveChannelProgressDraftMaxLineChars(params.entry),
+      );
+      if (!displayLine) {
+        return false;
+      }
+      if (previewToolProgressEnabled) {
+        const priorIndex =
+          lastReasoningLine === undefined ? -1 : lines.lastIndexOf(lastReasoningLine);
+        if (priorIndex >= 0) {
+          lines = [...lines];
+          lines[priorIndex] = displayLine;
+        } else {
+          lines = [...lines, displayLine].slice(-resolveChannelProgressDraftMaxLines(params.entry));
+        }
+        lastReasoningLine = displayLine;
+      }
+      const progressActive = await gate.noteWork();
+      if (progressActive && gate.hasStarted) {
+        return await render();
+      }
+      return false;
+    },
+    async pushCommentaryProgress(text?: string, options?: { itemId?: string }) {
+      if (!params.active || params.mode !== "progress" || !commentaryProgressEnabled) {
+        return false;
+      }
+      if (finalReplyStarted || finalReplyDelivered) {
+        return false;
+      }
+      const itemId = options?.itemId?.trim();
+      if (!text && !itemId) {
+        return false;
+      }
+      const normalized = normalizeCommentaryProgressText(text ?? "");
+      const lineId = itemId ? `commentary:${itemId}` : normalized ? `commentary:${normalized}` : "";
+      if (!normalized) {
+        if (lineId) {
+          await clearLine(lineId);
+        }
+        return false;
+      }
+      const line: ChannelProgressDraftLine = {
+        id: lineId,
+        kind: "item",
+        text: normalized,
+        label: "Commentary",
+        prefix: false,
+      };
+      lines = mergeChannelProgressDraftLine(lines, line, {
+        maxLines: resolveChannelProgressDraftMaxLines(params.entry),
+      });
+      await gate.startNow();
+      return await render();
+    },
+  };
+}
+
+function normalizeReasoningProgressLine(text: string): string {
+  return stripReasoningProgressTags(text)
+    .replace(
+      /^\s*(?:>\s*)?(?:Reasoning:\s*(?:\r?\n|\r)\s*|Thinking\.{0,3}\s*(?:\r?\n|\r)\s*(?:\r?\n|\r)\s*)/i,
+      "",
+    )
+    .replace(/\s+/g, " ")
+    .trim();
+}
+
+function stripReasoningProgressTags(text: string): string {
+  return text.replace(
+    /<\s*\/?\s*(?:(?:antml:)?(?:think(?:ing)?|thought)|antthinking)\b[^<>]*>/giu,
+    "",
+  );
+}
+
+function normalizeReasoningProgressInput(text: string): string {
+  const normalized = normalizeReasoningProgressLine(text);
+  const italic = normalized.match(/^_(.*)_$/u);
+  return (italic?.[1] ?? normalized).trim();
+}
+
+function formatReasoningProgressDisplayLine(text: string, maxChars: number): string {
+  const normalizedText = normalizeReasoningProgressInput(text);
+  const formatted = normalizeReasoningProgressLine(formatReasoningMessage(normalizedText));
+  if (!formatted) {
+    return "";
+  }
+  if (Array.from(formatted).length <= maxChars) {
+    return formatted;
+  }
+  const italic = formatted.match(/^_(.*)_$/u);
+  if (!italic) {
+    return compactReasoningProgressDisplayLine(formatted, maxChars);
+  }
+  const body = compactReasoningProgressDisplayLine(italic[1] ?? "", Math.max(1, maxChars - 2));
+  return body ? `_${body}_` : "";
+}
+
+function compactReasoningProgressDisplayLine(text: string, maxChars: number): string {
+  const normalized = text.replace(/\s+/g, " ").trim();
+  const chars = Array.from(normalized);
+  if (chars.length <= maxChars) {
+    return normalized;
+  }
+  if (maxChars <= 1) {
+    return "…";
+  }
+  const head = chars
+    .slice(0, maxChars - 1)
+    .join("")
+    .trimEnd();
+  const boundary = head.search(/\s+\S*$/u);
+  if (boundary > Math.floor(maxChars * 0.6)) {
+    return `${head.slice(0, boundary).trimEnd()}…`;
+  }
+  return `${head}…`;
+}
+
+function normalizeCommentaryProgressText(text: string): string {
+  const cleaned = stripInlineDirectiveTagsForDelivery(text).text.trim();
+  if (!cleaned || isSilentCommentaryProgressText(cleaned)) {
+    return "";
+  }
+  return cleaned
+    .split(/\r?\n/u)
+    .map((line) => line.replace(/\s+/g, " ").trim())
+    .filter(Boolean)
+    .map((line) => `_${line}_`)
+    .join("\n");
+}
+
+function isSilentCommentaryProgressText(text: string): boolean {
+  const normalized = text.replace(/^[\s*_`~]+|[\s*_`~]+$/gu, "").trim();
+  return /^NO_REPLY$/iu.test(normalized);
+}
+
+function mergeReasoningProgressText(
+  current: string,
+  incoming: string,
+  options?: { snapshot?: boolean },
+): string {
+  if (!current) {
+    return incoming;
+  }
+  const normalizedCurrent = normalizeReasoningProgressInput(current);
+  const normalizedIncoming = normalizeReasoningProgressInput(incoming);
+  if (!normalizedIncoming || normalizedIncoming === normalizedCurrent) {
+    return current;
+  }
+  if (
+    options?.snapshot === true ||
+    isReasoningSnapshotText(incoming) ||
+    normalizedIncoming.startsWith(normalizedCurrent)
+  ) {
+    return incoming;
+  }
+  return `${current}${incoming}`;
+}
+
+function isReasoningSnapshotText(text: string): boolean {
+  return /^\s*(?:>\s*)?(?:Reasoning:\s*(?:\r?\n|\r)\s*|Thinking\.{0,3}\s*(?:\r?\n|\r)\s*(?:\r?\n|\r)\s*)/i.test(
+    text,
+  );
+}
diff --git a/src/channels/streaming.ts b/src/channels/streaming.ts
index ce266928891..103f51f90a9 100644
--- a/src/channels/streaming.ts
+++ b/src/channels/streaming.ts
@@ -26,7 +26,7 @@ export type {
 } from "../config/types.base.js";
 export type { SlackChannelStreamingConfig } from "../config/types.slack.js";
 
-type StreamingCompatEntry = {
+export type StreamingCompatEntry = {
   streaming?: unknown;
   streamMode?: unknown;
   chunkMode?: unknown;
diff --git a/src/plugin-sdk/channel-outbound.ts b/src/plugin-sdk/channel-outbound.ts
index c051514acc5..413fd2db80a 100644
--- a/src/plugin-sdk/channel-outbound.ts
+++ b/src/plugin-sdk/channel-outbound.ts
@@ -75,6 +75,7 @@ export type { OutboundSendDeps } from "../infra/outbound/send-deps.js";
 export { sanitizeForPlainText } from "../infra/outbound/sanitize-text.js";
 export { logAckFailure, logTypingFailure } from "../channels/logging.js";
 export * from "../channels/streaming.js";
+export * from "../channels/progress-draft-compositor.js";
 export {
   classifyDurableSendRecoveryState,
   createChannelMessageAdapterFromOutbound,