diff --git a/apps/web/src/components/chat/ChatComposer.tsx b/apps/web/src/components/chat/ChatComposer.tsx
index 77dce596892d5..b1da45e74ab98 100644
--- a/apps/web/src/components/chat/ChatComposer.tsx
+++ b/apps/web/src/components/chat/ChatComposer.tsx
@@ -2346,6 +2346,8 @@ export const ChatComposer = memo(function ChatComposer(props: ChatComposerProps)
       composerMenuItemsRef,
       activeComposerMenuItemRef,
       setComposerDraftPrompt,
+      setComposerDraftThreadContexts,
+      setComposerDraftEnvironmentContexts,
       setComposerCursor,
       setComposerTrigger,
       setComposerHighlightedItemId,
diff --git a/apps/web/src/components/chat/composerCommandKey.ts b/apps/web/src/components/chat/composerCommandKey.ts
index 40650fe6c8952..243b69d09e4df 100644
--- a/apps/web/src/components/chat/composerCommandKey.ts
+++ b/apps/web/src/components/chat/composerCommandKey.ts
@@ -6,6 +6,7 @@ import {
 } from "@t3tools/client-runtime/state/composer-dispatch";
 import { type ComposerPromptEditorHandle } from "../ComposerPromptEditorTiptap";
 import {
+  type ComposerPromptHistoryMentions,
   type ComposerPromptHistoryPosition,
   buildComposerPromptHistoryEntries,
   stepComposerPromptHistory,
@@ -17,7 +18,11 @@ import {
   composerSubmissionIntentForKey,
 } from "../../composer-logic";
 import { type PendingUserInput } from "../../session-logic";
-import { type PreviewAnnotationPayload } from "@t3tools/contracts";
+import {
+  type EnvironmentContextRecord,
+  type PreviewAnnotationPayload,
+  type ThreadContextRecord,
+} from "@t3tools/contracts";
 import { type ReviewCommentContext } from "../../reviewCommentContext";
 import { composerTargetKey } from "../../composerDraftStore";
 import {
@@ -63,6 +68,14 @@ export function composerCommandKeyHandler(input: {
     target: ChatComposerProps["composerDraftTarget"],
     prompt: string,
   ) => void;
+  readonly setComposerDraftThreadContexts: (
+    target: ChatComposerProps["composerDraftTarget"],
+    records: ReadonlyArray<ThreadContextRecord>,
+  ) => void;
+  readonly setComposerDraftEnvironmentContexts: (
+    target: ChatComposerProps["composerDraftTarget"],
+    records: ReadonlyArray<EnvironmentContextRecord>,
+  ) => void;
   readonly setComposerCursor: Dispatch<SetStateAction<number>>;
   readonly setComposerTrigger: (trigger: ComposerTrigger | null) => void;
   readonly setComposerHighlightedItemId: Dispatch<SetStateAction<string | null>>;
@@ -110,6 +123,8 @@ export function composerCommandKeyHandler(input: {
     composerMenuItemsRef,
     activeComposerMenuItemRef,
     setComposerDraftPrompt,
+    setComposerDraftThreadContexts,
+    setComposerDraftEnvironmentContexts,
     setComposerCursor,
     setComposerTrigger,
     setComposerHighlightedItemId,
@@ -129,9 +144,14 @@ export function composerCommandKeyHandler(input: {
   // otherwise turn B's own draft into a browsing position.
   const promptHistoryTargetKey = composerTargetKey(composerDraftTarget);
 
-  const replacePromptFromHistory = (nextPrompt: string) => {
+  const replacePromptFromHistory = (
+    nextPrompt: string,
+    mentions: ComposerPromptHistoryMentions,
+  ) => {
     promptRef.current = nextPrompt;
     setComposerDraftPrompt(composerDraftTarget, nextPrompt);
+    setComposerDraftThreadContexts(composerDraftTarget, mentions.threadContexts);
+    setComposerDraftEnvironmentContexts(composerDraftTarget, mentions.environmentContexts);
     setComposerCursor(collapseExpandedComposerCursor(nextPrompt, nextPrompt.length));
     setComposerTrigger(null);
     setComposerHighlightedItemId(null);
@@ -176,7 +196,7 @@ export function composerCommandKeyHandler(input: {
     promptHistoryPositionRef.current = step.position
       ? { targetKey: promptHistoryTargetKey, position: step.position }
       : null;
-    replacePromptFromHistory(step.prompt);
+    replacePromptFromHistory(step.prompt, step.mentions);
     return true;
   };
 
diff --git a/apps/web/src/components/chat/composerPromptHistory.test.ts b/apps/web/src/components/chat/composerPromptHistory.test.ts
index 39bf0c1f21e74..fb1db28ed1646 100644
--- a/apps/web/src/components/chat/composerPromptHistory.test.ts
+++ b/apps/web/src/components/chat/composerPromptHistory.test.ts
@@ -1,4 +1,8 @@
-import { ScheduledTaskId } from "@t3tools/contracts";
+import { EnvironmentId, ScheduledTaskId, ThreadId } from "@t3tools/contracts";
+import {
+  formatComposerContextReference,
+  threadContextRecord,
+} from "@t3tools/shared/composerContextReferences";
 import { describe, expect, it } from "vite-plus/test";
 
 import {
@@ -7,6 +11,7 @@ import {
   stepComposerPromptHistory,
   type ComposerPromptHistoryPosition,
 } from "./composerPromptHistory";
+import { environmentContextRecord } from "../../lib/composerContextRecords";
 
 const entries = buildComposerPromptHistoryEntries([
   { id: "m1", role: "user", text: "first" },
@@ -94,13 +99,51 @@ describe("buildComposerPromptHistoryEntries", () => {
       { id: "m3", role: "user", text: "other" },
       { id: "m4", role: "user", text: "same" },
     ]);
-    expect(collapsed).toEqual([
+    expect(collapsed.map(({ id, prompt }) => ({ id, prompt }))).toEqual([
       { id: "m2", prompt: "same" },
       { id: "m3", prompt: "other" },
       { id: "m4", prompt: "same" },
     ]);
   });
 
+  it("keeps thread and machine mentions with the records the draft needs to resolve them", () => {
+    const environmentId = EnvironmentId.make("env-1");
+    const thread = threadContextRecord(
+      { environmentId, threadId: ThreadId.make("thread-1") },
+      "Correct invoice charge categories",
+    );
+    const unmentioned = threadContextRecord(
+      { environmentId, threadId: ThreadId.make("thread-2") },
+      "Removed before send",
+    );
+    const machine = environmentContextRecord(environmentId, "Build box");
+    const threadChip = formatComposerContextReference(thread);
+    const machineChip = formatComposerContextReference(machine);
+    const [entry] = buildComposerPromptHistoryEntries([
+      {
+        id: "m1",
+        role: "user",
+        text: `Agent in ${threadChip} finished on ${machineChip}. See [Gone](t3-context://v1/thread/gone) ![shot](t3-context://v1/image/img-1)`,
+        context: { version: 1, records: [thread, unmentioned, machine] },
+      },
+    ]);
+    expect(entry).toEqual({
+      id: "m1",
+      prompt: `Agent in ${threadChip} finished on ${machineChip}. See`,
+      mentions: { threadContexts: [thread], environmentContexts: [machine] },
+    });
+    const recalled = stepComposerPromptHistory({
+      direction: "backward",
+      entries: [entry!],
+      position: null,
+      currentPrompt: "",
+    });
+    expect(recalled?.mentions).toEqual({
+      threadContexts: [thread],
+      environmentContexts: [machine],
+    });
+  });
+
   it("skips messages sent by automations, agents, and T3 Code", () => {
     const typed = buildComposerPromptHistoryEntries([
       { id: "m1", role: "user", text: "typed" },
@@ -113,21 +156,28 @@ describe("buildComposerPromptHistoryEntries", () => {
       { id: "m3", role: "user", text: "from agent", createdBy: "agent", creationSource: "mcp" },
       { id: "m4", role: "user", text: "from server", createdBy: "agent", creationSource: "server" },
     ]);
-    expect(typed).toEqual([{ id: "m1", prompt: "typed" }]);
+    expect(typed.map((entry) => entry.id)).toEqual(["m1"]);
   });
 });
 
 describe("stepComposerPromptHistory", () => {
   it("walks back from the newest entry", () => {
     const first = backward(null, "");
-    expect(first).toEqual({ position: { entryId: "m3", recalled: "third" }, prompt: "third" });
+    expect(first).toMatchObject({
+      position: { entryId: "m3", recalled: "third" },
+      prompt: "third",
+    });
     expect(backward(first!.position, "third")?.prompt).toBe("second");
   });
 
   it("walks forward and empties the composer past the newest entry", () => {
     const newer = forward({ entryId: "m2", recalled: "second" }, "second");
     expect(newer?.prompt).toBe("third");
-    expect(forward(newer!.position, "third")).toEqual({ position: null, prompt: "" });
+    expect(forward(newer!.position, "third")).toEqual({
+      position: null,
+      prompt: "",
+      mentions: { threadContexts: [], environmentContexts: [] },
+    });
   });
 
   it("treats an edited recall as a fresh draft", () => {
diff --git a/apps/web/src/components/chat/composerPromptHistory.ts b/apps/web/src/components/chat/composerPromptHistory.ts
index 0d3f68b674b5e..a4f4ed62a7c04 100644
--- a/apps/web/src/components/chat/composerPromptHistory.ts
+++ b/apps/web/src/components/chat/composerPromptHistory.ts
@@ -1,8 +1,14 @@
 import { resolveUserMessagePresentation } from "@t3tools/client-runtime/user-message";
+import {
+  EnvironmentContextRecord,
+  type OrchestrationMessageContext,
+  ThreadContextRecord,
+} from "@t3tools/contracts";
 import {
   ATTACHMENT_ONLY_BOOTSTRAP_PROMPT,
   collectComposerContextReferences,
 } from "@t3tools/shared/composerContextReferences";
+import { Schema } from "effect";
 import { PLAN_IMPLEMENTATION_PROMPT_PREFIX } from "../../proposedPlan";
 
 const CLAUDE_ULTRATHINK_PREFIX = "Ultrathink:\n";
@@ -10,13 +16,26 @@ const REVIEW_COMMENT_BLOCK_PATTERN = /<review_comment\b[^>]*>[\s\S]*?<\/review_c
 const TRAILING_LEGACY_CONTEXT =
   /\n*<(terminal_context|element_context|preview_annotation)>\n([\s\S]*?)\n<\/\1>\s*$/;
 
+const isThreadContextRecord = Schema.is(ThreadContextRecord);
+const isEnvironmentContextRecord = Schema.is(EnvironmentContextRecord);
+
 type ComposerPromptHistoryMessage = Parameters<typeof resolveUserMessagePresentation>[0] & {
   readonly id: string;
+  readonly context?: OrchestrationMessageContext | undefined;
 };
 
+/** Thread and machine mentions; the draft holds these records, so recall can restore their chips. */
+export interface ComposerPromptHistoryMentions {
+  readonly threadContexts: ReadonlyArray<ThreadContextRecord>;
+  readonly environmentContexts: ReadonlyArray<EnvironmentContextRecord>;
+}
+
+const NO_MENTIONS: ComposerPromptHistoryMentions = { threadContexts: [], environmentContexts: [] };
+
 interface ComposerPromptHistoryEntry {
   readonly id: string;
   readonly prompt: string;
+  readonly mentions: ComposerPromptHistoryMentions;
 }
 
 export interface ComposerPromptHistoryPosition {
@@ -36,6 +55,7 @@ function findActive(
 interface ComposerPromptHistoryStep {
   readonly position: ComposerPromptHistoryPosition | null;
   readonly prompt: string;
+  readonly mentions: ComposerPromptHistoryMentions;
 }
 
 function stripTrailingReviewComments(prompt: string): string {
@@ -70,7 +90,10 @@ function stripInlineTerminalLabels(prompt: string, headers: ReadonlyArray<string
   return result;
 }
 
-export function recallableComposerPrompt(messageText: string): string {
+export function recallableComposerPrompt(
+  messageText: string,
+  keptContextIds: ReadonlySet<string> = new Set(),
+): string {
   let prompt = messageText.trim();
   if (prompt.startsWith(CLAUDE_ULTRATHINK_PREFIX)) {
     prompt = prompt.slice(CLAUDE_ULTRATHINK_PREFIX.length);
@@ -99,8 +122,9 @@ export function recallableComposerPrompt(messageText: string): string {
     break;
   }
 
-  // Recall strips chips because their backing records are absent.
+  // Chips without a record the draft can hold would render as unavailable.
   for (const reference of collectComposerContextReferences(prompt).toReversed()) {
+    if (keptContextIds.has(reference.contextId)) continue;
     let { start, end } = reference;
     if (prompt[end] === " ") end += 1;
     else if (prompt[start - 1] === " ") start -= 1;
@@ -117,6 +141,29 @@ export function recallableComposerPrompt(messageText: string): string {
   return trimmed;
 }
 
+function recallMessage(
+  message: ComposerPromptHistoryMessage,
+): Pick<ComposerPromptHistoryEntry, "prompt" | "mentions"> {
+  const records = message.context?.records ?? [];
+  const threadRecords = records.filter(isThreadContextRecord);
+  const environmentRecords = records.filter(isEnvironmentContextRecord);
+  const prompt = recallableComposerPrompt(
+    message.text,
+    new Set([...threadRecords, ...environmentRecords].map((record) => record.contextId)),
+  );
+  // A record whose chip is gone from the text would put the chip back when written to the draft.
+  const referenced = new Set<string>(
+    collectComposerContextReferences(prompt).map((reference) => reference.contextId),
+  );
+  return {
+    prompt,
+    mentions: {
+      threadContexts: threadRecords.filter((record) => referenced.has(record.contextId)),
+      environmentContexts: environmentRecords.filter((record) => referenced.has(record.contextId)),
+    },
+  };
+}
+
 export function buildComposerPromptHistoryEntries(
   messages: ReadonlyArray<ComposerPromptHistoryMessage>,
 ): ComposerPromptHistoryEntry[] {
@@ -125,18 +172,27 @@ export function buildComposerPromptHistoryEntries(
     if (message.role !== "user") continue;
     // Automations and other agents send user-role messages; recall only what the user typed.
     if (resolveUserMessagePresentation(message).attribution !== null) continue;
-    const prompt = recallableComposerPrompt(message.text);
+    const { prompt, mentions } = recallMessage(message);
     if (prompt.length === 0) continue;
+    const entry = { id: message.id, prompt, mentions };
     const previous = entries[entries.length - 1];
     if (previous && previous.prompt === prompt) {
-      entries[entries.length - 1] = { id: message.id, prompt };
+      entries[entries.length - 1] = entry;
       continue;
     }
-    entries.push({ id: message.id, prompt });
+    entries.push(entry);
   }
   return entries;
 }
 
+function recall(entry: ComposerPromptHistoryEntry): ComposerPromptHistoryStep {
+  return {
+    position: { entryId: entry.id, recalled: entry.prompt },
+    prompt: entry.prompt,
+    mentions: entry.mentions,
+  };
+}
+
 export function stepComposerPromptHistory(input: {
   readonly direction: "backward" | "forward";
   readonly entries: ReadonlyArray<ComposerPromptHistoryEntry>;
@@ -151,11 +207,11 @@ export function stepComposerPromptHistory(input: {
     if (activeIndex < 0 && currentPrompt.length > 0) return null;
     const entry = entries[activeIndex < 0 ? entries.length - 1 : activeIndex - 1];
     if (!entry) return null;
-    return { position: { entryId: entry.id, recalled: entry.prompt }, prompt: entry.prompt };
+    return recall(entry);
   }
 
   if (activeIndex < 0) return null;
   const entry = entries[activeIndex + 1];
-  if (!entry) return { position: null, prompt: "" };
-  return { position: { entryId: entry.id, recalled: entry.prompt }, prompt: entry.prompt };
+  if (!entry) return { position: null, prompt: "", mentions: NO_MENTIONS };
+  return recall(entry);
 }