diff --git a/apps/web/package.json b/apps/web/package.json
index 8b8aec8ffa577..0a322d21ec71f 100644
--- a/apps/web/package.json
+++ b/apps/web/package.json
@@ -69,6 +69,7 @@
     "react-dom": "19.2.6",
     "react-markdown": "^10.1.0",
     "remark-gfm": "catalog:",
+    "remark-parse": "catalog:",
     "tailwind-merge": "^3.4.0",
     "unbash": "^5.0.0",
     "zustand": "^5.0.11"
diff --git a/apps/web/src/components/ChatMarkdown.tsx b/apps/web/src/components/ChatMarkdown.tsx
index fcf193a45590e..0e58c94f7c8b2 100644
--- a/apps/web/src/components/ChatMarkdown.tsx
+++ b/apps/web/src/components/ChatMarkdown.tsx
@@ -52,6 +52,7 @@ import {
   type EnvironmentId,
   type ScopedThreadRef,
   type ServerProviderSkill,
+  type TableCopyFormat,
   type ThreadPullRequestKey,
 } from "@t3tools/contracts";
 import { faviconUrlForOrigin } from "@t3tools/shared/favicon";
@@ -162,7 +163,7 @@ import { useTheme } from "../hooks/useTheme";
 import { getClientSettings, useClientSettings } from "../hooks/useSettings";
 import {
   chatMarkdownClipboardPayload,
-  serializeTableElementToCsv,
+  serializeTableElementToDelimited,
   serializeTableElementToMarkdown,
 } from "../markdown-clipboard";
 import {
@@ -350,7 +351,7 @@ const MAX_HIGHLIGHT_CACHE_MEMORY_BYTES = 50 * 1024 * 1024;
 interface MarkdownActionFailureContext {
   readonly operation: string;
   readonly target?: string;
-  readonly format?: "markdown" | "csv";
+  readonly format?: TableCopyFormat;
   readonly language?: string;
   readonly fenceTitle?: string;
   readonly copyTarget?: string;
@@ -573,7 +574,7 @@ function MarkdownTable({ children, ...props }: React.ComponentProps<"table">) {
     setExpanded((value) => !value);
   }
 
-  const handleCopy = useCallback((format: "markdown" | "csv") => {
+  const handleCopy = useCallback((format: TableCopyFormat) => {
     const table = containerRef.current?.querySelector("table");
     if (!table || typeof navigator === "undefined" || navigator.clipboard == null) {
       return;
@@ -581,7 +582,7 @@ function MarkdownTable({ children, ...props }: React.ComponentProps<"table">) {
     const text =
       format === "markdown"
         ? serializeTableElementToMarkdown(table)
-        : serializeTableElementToCsv(table);
+        : serializeTableElementToDelimited(table, format);
     void navigator.clipboard
       .writeText(text)
       .then(() => {
@@ -660,6 +661,7 @@ function MarkdownTable({ children, ...props }: React.ComponentProps<"table">) {
           </Tooltip>
           <MenuPopup align="end">
             <MenuItem onClick={() => handleCopy("markdown")}>Copy as Markdown</MenuItem>
+            <MenuItem onClick={() => handleCopy("tsv")}>Copy as TSV</MenuItem>
             <MenuItem onClick={() => handleCopy("csv")}>Copy as CSV</MenuItem>
           </MenuPopup>
         </Menu>
@@ -2404,7 +2406,7 @@ function useChatMarkdownState({
   const handleCopy = useCallback((event: ReactClipboardEvent<HTMLDivElement>) => {
     const selection = window.getSelection();
     if (!selection || selection.isCollapsed || !event.clipboardData) return;
-    const payload = chatMarkdownClipboardPayload(selection);
+    const payload = chatMarkdownClipboardPayload(selection, getClientSettings().tableCopyFormat);
     if (!payload) return;
     event.preventDefault();
     event.clipboardData.setData("text/plain", payload.text);
diff --git a/apps/web/src/components/chat/MessageCopyButton.tsx b/apps/web/src/components/chat/MessageCopyButton.tsx
index 361f9a6c2a5bc..4238297169613 100644
--- a/apps/web/src/components/chat/MessageCopyButton.tsx
+++ b/apps/web/src/components/chat/MessageCopyButton.tsx
@@ -20,7 +20,7 @@ export const MessageCopyButton = memo(function MessageCopyButton({
   variant = "outline",
   className,
 }: {
-  text: string;
+  text: string | (() => string);
   label?: string;
   icon?: typeof Copy;
   extraFlavors?: Readonly<Record<string, string>>;
@@ -43,7 +43,7 @@ export const MessageCopyButton = memo(function MessageCopyButton({
           <Button
             aria-label={label}
             disabled={isCopied}
-            onClick={() => copyToClipboard(text)}
+            onClick={() => copyToClipboard(typeof text === "function" ? text() : text)}
             ref={ref}
             type="button"
             size={size}
diff --git a/apps/web/src/components/chat/MessagesTimeline.tsx b/apps/web/src/components/chat/MessagesTimeline.tsx
index e2a3b9dfd6003..913ad292bf916 100644
--- a/apps/web/src/components/chat/MessagesTimeline.tsx
+++ b/apps/web/src/components/chat/MessagesTimeline.tsx
@@ -266,11 +266,14 @@ import {
   encodeComposerContextClipboardHtml,
   encodeComposerContextFragment,
 } from "@t3tools/shared/composerContextClipboard";
-import { chatMarkdownClipboardPayload } from "../../markdown-clipboard";
+import {
+  chatMarkdownClipboardPayload,
+  markdownWithTableCopyFormat,
+} from "../../markdown-clipboard";
 import { ContextChip, ContextChipLabel, type ContextChipKind } from "../ContextChip";
 import { createContextPresentationRegistry } from "../contextPresentationRegistry";
 import { useOpenPrLink } from "~/lib/openPullRequestLink";
-import { useClientSettings } from "~/hooks/useSettings";
+import { getClientSettings, useClientSettings } from "~/hooks/useSettings";
 import type { ChatMarkdownContextReference } from "../ChatMarkdown";
 import { useMediaQuery } from "~/hooks/useMediaQuery";
 import { cn } from "~/lib/utils";
@@ -2940,7 +2943,13 @@ function AssistantCopyButton({
     return null;
   }
 
-  return <MessageCopyButton text={assistantCopyState.text ?? ""} variant="ghost" />;
+  const text = assistantCopyState.text ?? "";
+  return (
+    <MessageCopyButton
+      text={() => markdownWithTableCopyFormat(text, getClientSettings().tableCopyFormat)}
+      variant="ghost"
+    />
+  );
 }
 
 function ProposedPlanTimelineRow({
diff --git a/apps/web/src/components/settings/SettingsPanels.tsx b/apps/web/src/components/settings/SettingsPanels.tsx
index fcdc35b3c1042..8f111b1cae46e 100644
--- a/apps/web/src/components/settings/SettingsPanels.tsx
+++ b/apps/web/src/components/settings/SettingsPanels.tsx
@@ -27,6 +27,7 @@ import {
   DEFAULT_ENVIRONMENT_IDENTIFICATION_MODE,
   DEFAULT_UNIFIED_SETTINGS,
   type ChatWidth,
+  type TableCopyFormat,
   type DiffLayout,
   type EnvironmentIdentificationMode,
   MAX_APPEARANCE_CONTRAST,
@@ -200,6 +201,12 @@ const TIMESTAMP_FORMAT_LABELS = {
   "24-hour": "24-hour",
 } as const;
 
+const TABLE_COPY_FORMAT_LABELS: Record<TableCopyFormat, string> = {
+  markdown: "Markdown",
+  tsv: "Tab-separated",
+  csv: "CSV",
+};
+
 const CHAT_WIDTH_LABELS: Record<ChatWidth, string> = {
   comfortable: "Comfortable",
   wide: "Wide",
@@ -551,6 +558,9 @@ export function useSettingsRestore(onRestored?: () => void) {
       DEFAULT_UNIFIED_SETTINGS.environmentIdentificationMode
         ? ["Environment identification"]
         : []),
+      ...(settings.tableCopyFormat !== DEFAULT_UNIFIED_SETTINGS.tableCopyFormat
+        ? ["Table copy format"]
+        : []),
       ...(settings.timestampFormat !== DEFAULT_UNIFIED_SETTINGS.timestampFormat
         ? ["Time format"]
         : []),
@@ -719,6 +729,7 @@ export function useSettingsRestore(onRestored?: () => void) {
       settings.sidebarThreadPreviewCount,
       settings.showSkillsInSlashMenu,
       settings.timestampFormat,
+      settings.tableCopyFormat,
       settings.notificationMode,
       settings.inAppNotificationsEnabled,
       settings.wordWrap,
@@ -789,6 +800,7 @@ export function useSettingsRestore(onRestored?: () => void) {
       diffColorScheme: DEFAULT_UNIFIED_SETTINGS.diffColorScheme,
       chatWidth: DEFAULT_UNIFIED_SETTINGS.chatWidth,
       timestampFormat: DEFAULT_UNIFIED_SETTINGS.timestampFormat,
+      tableCopyFormat: DEFAULT_UNIFIED_SETTINGS.tableCopyFormat,
       notificationMode: DEFAULT_UNIFIED_SETTINGS.notificationMode,
       inAppNotificationsEnabled: DEFAULT_UNIFIED_SETTINGS.inAppNotificationsEnabled,
       wordWrap: DEFAULT_UNIFIED_SETTINGS.wordWrap,
@@ -2505,6 +2517,47 @@ export function GeneralSettingsPanel() {
             </Select>
           }
         />
+        <SettingsRow
+          {...searchableSetting("table-copy-format")}
+          description="How tables are written when you copy a message or a selection. Tab-separated pastes as a table into Slack and spreadsheets."
+          resetAction={
+            settings.tableCopyFormat !== DEFAULT_UNIFIED_SETTINGS.tableCopyFormat ? (
+              <SettingResetButton
+                label="table copy format"
+                onClick={() =>
+                  updateSettings({
+                    tableCopyFormat: DEFAULT_UNIFIED_SETTINGS.tableCopyFormat,
+                  })
+                }
+              />
+            ) : null
+          }
+          control={
+            <Select
+              value={settings.tableCopyFormat}
+              onValueChange={(value) => {
+                if (value === "markdown" || value === "tsv" || value === "csv") {
+                  updateSettings({ tableCopyFormat: value });
+                }
+              }}
+            >
+              <SelectTrigger size="sm" className="w-full sm:w-40" aria-label="Table copy format">
+                <SelectValue>{TABLE_COPY_FORMAT_LABELS[settings.tableCopyFormat]}</SelectValue>
+              </SelectTrigger>
+              <SelectPopup align="end" alignItemWithTrigger={false}>
+                <SelectItem hideIndicator value="markdown">
+                  {TABLE_COPY_FORMAT_LABELS.markdown}
+                </SelectItem>
+                <SelectItem hideIndicator value="tsv">
+                  {TABLE_COPY_FORMAT_LABELS.tsv}
+                </SelectItem>
+                <SelectItem hideIndicator value="csv">
+                  {TABLE_COPY_FORMAT_LABELS.csv}
+                </SelectItem>
+              </SelectPopup>
+            </Select>
+          }
+        />
         <SettingsRow
           serverScoped
           settingKeys={["responseStreamingMode"]}
diff --git a/apps/web/src/components/settings/settingsSearch.ts b/apps/web/src/components/settings/settingsSearch.ts
index 53032977f5adb..15d3a4abc5cef 100644
--- a/apps/web/src/components/settings/settingsSearch.ts
+++ b/apps/web/src/components/settings/settingsSearch.ts
@@ -365,6 +365,12 @@ export const SETTINGS_SEARCH_ITEMS = [
     to: "/settings/general",
     searchTerms: ["timestamp clock locale system browser os 12 hour 24 hour"],
   },
+  {
+    id: "table-copy-format",
+    title: "Table copy format",
+    to: "/settings/general",
+    searchTerms: ["clipboard markdown tsv csv tab separated spreadsheet slack paste"],
+  },
   {
     id: "response-streaming",
     title: "Response streaming",
diff --git a/apps/web/src/markdown-clipboard.selection.test.ts b/apps/web/src/markdown-clipboard.selection.test.ts
new file mode 100644
index 0000000000000..3463a0b65aca9
--- /dev/null
+++ b/apps/web/src/markdown-clipboard.selection.test.ts
@@ -0,0 +1,64 @@
+// @vitest-environment jsdom
+
+import { afterEach, describe, expect, it } from "vite-plus/test";
+
+import { chatMarkdownClipboardPayload } from "./markdown-clipboard";
+
+function selectBetween(start: Node, end: Node): Selection {
+  const range = document.createRange();
+  range.setStart(start, 0);
+  range.setEnd(end, end.childNodes.length);
+  const selection = window.getSelection();
+  if (!selection) throw new Error("jsdom has no selection");
+  selection.removeAllRanges();
+  selection.addRange(range);
+  return selection;
+}
+
+describe("chatMarkdownClipboardPayload", () => {
+  afterEach(() => {
+    document.body.innerHTML = "";
+  });
+
+  it("copies a selection spanning table rows as rows, even though the range omits the table", () => {
+    document.body.innerHTML = `
+      <table>
+        <thead><tr><th>Question</th><th>Owner</th></tr></thead>
+        <tbody><tr><td>Loader URL?</td><td>Platform</td></tr></tbody>
+      </table>`;
+    const cells = document.querySelectorAll("th, td");
+    const selection = selectBetween(cells[0]!, cells[3]!);
+
+    expect(chatMarkdownClipboardPayload(selection, "tsv")?.text).toBe(
+      "Question\tOwner\nLoader URL?\tPlatform",
+    );
+    expect(chatMarkdownClipboardPayload(selection)?.text).toBe(
+      "| Question | Owner |\n| --- | --- |\n| Loader URL? | Platform |",
+    );
+  });
+
+  it("keeps empty edge cells, line breaks, and image alt text inside cells", () => {
+    document.body.innerHTML = `
+      <p>Status</p>
+      <table>
+        <thead><tr><th>Question</th><th>Owner</th></tr></thead>
+        <tbody>
+          <tr><td></td><td>Platform</td></tr>
+          <tr><td>first<br>second</td><td></td></tr>
+          <tr><td><img alt="Build badge" src="b.svg"></td><td>ok</td></tr>
+        </tbody>
+      </table>`;
+    const selection = selectBetween(document.body, document.body);
+
+    expect(chatMarkdownClipboardPayload(selection, "tsv")?.text).toBe(
+      "Status\n\nQuestion\tOwner\n\tPlatform\nfirst second\t\nBuild badge\tok",
+    );
+  });
+
+  it("keeps a selection inside one cell as plain text", () => {
+    document.body.innerHTML = `<table><tbody><tr><td>Platform</td></tr></tbody></table>`;
+    const cell = document.querySelector("td")!;
+
+    expect(chatMarkdownClipboardPayload(selectBetween(cell, cell), "tsv")?.text).toBe("Platform");
+  });
+});
diff --git a/apps/web/src/markdown-clipboard.table.test.ts b/apps/web/src/markdown-clipboard.table.test.ts
new file mode 100644
index 0000000000000..f0ac9a7c78d1b
--- /dev/null
+++ b/apps/web/src/markdown-clipboard.table.test.ts
@@ -0,0 +1,35 @@
+// @vitest-environment jsdom
+
+import { describe, expect, it } from "vite-plus/test";
+
+import { serializeTableElementToDelimited } from "./markdown-clipboard";
+
+function renderTable(html: string): HTMLTableElement {
+  const container = document.createElement("div");
+  container.innerHTML = html;
+  return container.querySelector("table")!;
+}
+
+describe("serializeTableElementToDelimited", () => {
+  const table = renderTable(`
+    <table>
+      <thead><tr><th>Question</th><th>Owner, team</th></tr></thead>
+      <tbody>
+        <tr><td></td><td>Platform</td></tr>
+        <tr><td>first<br>second\tthird</td><td></td></tr>
+        <tr><td><img alt="Build badge" src="b.svg"></td><td>say "ok"</td></tr>
+      </tbody>
+    </table>`);
+
+  it("keeps every cell in its column as tab-separated rows", () => {
+    expect(serializeTableElementToDelimited(table, "tsv")).toBe(
+      'Question\tOwner, team\n\tPlatform\nfirst second third\t\nBuild badge\tsay "ok"',
+    );
+  });
+
+  it("quotes CSV cells that contain commas or quotes", () => {
+    expect(serializeTableElementToDelimited(table, "csv")).toBe(
+      'Question,"Owner, team"\n,Platform\nfirst second third,\nBuild badge,"say ""ok"""',
+    );
+  });
+});
diff --git a/apps/web/src/markdown-clipboard.test.ts b/apps/web/src/markdown-clipboard.test.ts
index c0535e78cec16..7646f612251b6 100644
--- a/apps/web/src/markdown-clipboard.test.ts
+++ b/apps/web/src/markdown-clipboard.test.ts
@@ -1,6 +1,9 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from "vite-plus/test";
 
-import { serializeRenderedMarkdownFragment } from "./markdown-clipboard";
+import {
+  markdownWithTableCopyFormat,
+  serializeRenderedMarkdownFragment,
+} from "./markdown-clipboard";
 import { EnvironmentId, MessageId, ThreadId } from "@t3tools/contracts";
 import {
   collectAssistantCitations,
@@ -331,3 +334,54 @@ describe("serializeRenderedMarkdownFragment", () => {
     );
   });
 });
+
+describe("markdownWithTableCopyFormat", () => {
+  const message = [
+    "Here is the status.",
+    "",
+    "| Question | Answer |",
+    "| --- | --- |",
+    "| **Loader** URL? | See [docs](https://example.com) and `v2\\|v3` |",
+    "| Owner, team | Platform |",
+    "| ![Build badge](https://example.com/b.svg) | ok |",
+    "",
+    "```md",
+    "| a | b |",
+    "| - | - |",
+    "```",
+  ].join("\n");
+
+  it("rewrites tables as plain-text tab-separated rows and leaves everything else alone", () => {
+    expect(markdownWithTableCopyFormat(message, "tsv")).toBe(
+      [
+        "Here is the status.",
+        "",
+        "Question\tAnswer",
+        "Loader URL?\tSee docs and v2|v3",
+        "Owner, team\tPlatform",
+        "Build badge\tok",
+        "",
+        "```md",
+        "| a | b |",
+        "| - | - |",
+        "```",
+      ].join("\n"),
+    );
+  });
+
+  it("fits each row to the header's width, as the rendered table does", () => {
+    const ragged = ["| a | b |", "| - | - |", "| 1 | 2 | 3 |", "| x |"].join("\n");
+
+    expect(markdownWithTableCopyFormat(ragged, "tsv")).toBe("a\tb\n1\t2\nx\t");
+  });
+
+  it("drops the quote prefix from every row of a quoted table", () => {
+    const quoted = ["> Note", ">", "> | a | b |", "> | - | - |", "> | 1 | 2 |"].join("\n");
+
+    expect(markdownWithTableCopyFormat(quoted, "tsv")).toBe("> Note\n>\na\tb\n1\t2");
+  });
+
+  it("quotes CSV cells that contain commas", () => {
+    expect(markdownWithTableCopyFormat(message, "csv")).toContain('"Owner, team",Platform');
+  });
+});
diff --git a/apps/web/src/markdown-clipboard.ts b/apps/web/src/markdown-clipboard.ts
index 4f941ce491232..27ffc50389934 100644
--- a/apps/web/src/markdown-clipboard.ts
+++ b/apps/web/src/markdown-clipboard.ts
@@ -1,3 +1,9 @@
+import type { TableCopyFormat } from "@t3tools/contracts";
+import type { Nodes, Table } from "mdast";
+import remarkGfm from "remark-gfm";
+import remarkParse from "remark-parse";
+import { unified } from "unified";
+
 const SKIPPED_TAGS = new Set(["BUTTON", "INPUT", "SCRIPT", "STYLE", "TEMPLATE"]);
 const SKIPPED_CLASS_NAMES = ["select-none", "sr-only"];
 const SANITIZED_HTML_SELECTOR = [
@@ -311,32 +317,132 @@ function tidyMarkdown(markdown: string): string {
     .trim();
 }
 
-export function serializeRenderedMarkdownFragment(container: Node): string {
+/**
+ * Serializes a rendered fragment back to markdown. Tables follow `tableFormat`;
+ * delimited formats replace each table with its TSV or CSV rows.
+ */
+export function serializeRenderedMarkdownFragment(
+  container: Node,
+  tableFormat: TableCopyFormat = "markdown",
+): string {
   const codeBlock = soleCodeBlock(container);
   if (codeBlock) return (codeBlock.textContent ?? "").replace(/\n$/, "");
-  return tidyMarkdown(serializeChildren(container));
+  if (tableFormat === "markdown" || container.nodeType !== Node.ELEMENT_NODE) {
+    return tidyMarkdown(serializeChildren(container));
+  }
+  // Tag a copy so the caller's fragment still produces untouched HTML. Tables
+  // stay placeholders through tidyMarkdown, which would strip the tabs of empty
+  // edge cells and shift the columns after them. The per-copy marker cannot
+  // collide with copied text.
+  const tagged = container.cloneNode(true) as Element;
+  const marker = `\uE000${Math.random().toString(36).slice(2)}\uE000`;
+  const delimitedTables: string[] = [];
+  for (const table of tagged.querySelectorAll("table")) {
+    table.setAttribute("data-markdown-copy", `${marker}${delimitedTables.length}${marker}\n\n`);
+    delimitedTables.push(serializeTableElementToDelimited(table, tableFormat));
+  }
+  return tidyMarkdown(serializeChildren(tagged)).replace(
+    new RegExp(`${marker}(\\d+)${marker}`, "g"),
+    (match, index: string) => delimitedTables[Number(index)] ?? match,
+  );
 }
 
 export function serializeTableElementToMarkdown(table: Element): string {
   return serializeTable(table).trim();
 }
 
-function csvCell(value: string): string {
+/** Collapses a cell to one line so it cannot break the row or column grid. */
+function delimitedCell(value: string, format: "tsv" | "csv"): string {
   const normalized = value.replace(/\s+/g, " ").trim();
+  if (format === "tsv") return normalized;
   return /[",\n]/.test(normalized) ? `"${normalized.replaceAll('"', '""')}"` : normalized;
 }
 
-export function serializeTableElementToCsv(table: Element): string {
-  const rows = [...table.querySelectorAll(":scope > thead > tr, :scope > tbody > tr, :scope > tr")];
-  const lines: string[] = [];
-  for (const row of rows) {
-    const cells = [...row.children].filter(
-      (cell) => cell.tagName === "TH" || cell.tagName === "TD",
+function delimitedRows(rows: ReadonlyArray<ReadonlyArray<string>>, format: "tsv" | "csv"): string {
+  const separator = format === "tsv" ? "\t" : ",";
+  return rows
+    .map((cells) => cells.map((cell) => delimitedCell(cell, format)).join(separator))
+    .join("\n");
+}
+
+/**
+ * Cell text with `<br>` kept as a word boundary and images as their alt text,
+ * both of which `textContent` drops.
+ */
+function tableCellText(node: Node): string {
+  if (node.nodeType === Node.TEXT_NODE) return node.textContent ?? "";
+  if (node.nodeType !== Node.ELEMENT_NODE) return "";
+  const element = node as Element;
+  if (element.tagName === "BR") return " ";
+  if (element.tagName === "IMG") return element.getAttribute("alt") ?? "";
+  return [...node.childNodes].map(tableCellText).join("");
+}
+
+/**
+ * Tab-separated rows are what spreadsheets put on the clipboard, and what Slack
+ * and spreadsheet apps turn back into a real table on paste.
+ */
+export function serializeTableElementToDelimited(table: Element, format: "tsv" | "csv"): string {
+  const rows = [...table.querySelectorAll(":scope > thead > tr, :scope > tbody > tr, :scope > tr")]
+    .map((row) =>
+      [...row.children]
+        .filter((cell) => cell.tagName === "TH" || cell.tagName === "TD")
+        .map(tableCellText),
+    )
+    .filter((cells) => cells.length > 0);
+  return delimitedRows(rows, format);
+}
+
+const markdownTableParser = unified().use(remarkParse).use(remarkGfm);
+
+function markdownPlainText(node: Nodes): string {
+  if (node.type === "html" || node.type === "break") return " ";
+  if (node.type === "image" || node.type === "imageReference") return node.alt ?? "";
+  if ("value" in node) return node.value;
+  if ("children" in node) return node.children.map(markdownPlainText).join("");
+  return "";
+}
+
+function collectMarkdownTables(node: Nodes, tables: Table[]): void {
+  if (node.type === "table") {
+    tables.push(node);
+    return;
+  }
+  if ("children" in node) {
+    for (const child of node.children) collectMarkdownTables(child, tables);
+  }
+}
+
+/**
+ * Rewrites GFM tables in markdown source as TSV or CSV, leaving the rest of the
+ * message untouched. Used when copying a whole message; cells become plain text.
+ */
+export function markdownWithTableCopyFormat(markdown: string, format: TableCopyFormat): string {
+  if (format === "markdown" || !markdown.includes("|")) return markdown;
+  const tables: Table[] = [];
+  collectMarkdownTables(markdownTableParser.parse(markdown), tables);
+  let result = markdown;
+  for (const table of tables.toReversed()) {
+    const start = table.position?.start.offset;
+    const end = table.position?.end.offset;
+    if (start === undefined || end === undefined) continue;
+    // GFM pads short rows and drops surplus cells to the header's width when
+    // rendering; the syntax tree keeps them as written.
+    const width = table.align?.length ?? table.children[0]?.children.length ?? 0;
+    const rows = table.children.map((row) =>
+      Array.from({ length: width }, (_, index) => {
+        const cell = row.children[index];
+        return cell ? markdownPlainText(cell) : "";
+      }),
     );
-    if (cells.length === 0) continue;
-    lines.push(cells.map((cell) => csvCell(cell.textContent ?? "")).join(","));
+    // A table in a blockquote or list starts after its line's container prefix
+    // ("> ", indentation) and swallows that prefix on later lines. Replace from
+    // the line start so no row keeps a stray marker.
+    const lineStart = result.lastIndexOf("\n", start - 1) + 1;
+    const replaceFrom = /^[\s>]*$/.test(result.slice(lineStart, start)) ? lineStart : start;
+    result = `${result.slice(0, replaceFrom)}${delimitedRows(rows, format)}${result.slice(end)}`;
   }
-  return lines.join("\n");
+  return result;
 }
 
 function sanitizedHtmlFrom(container: Element): string {
@@ -355,19 +461,40 @@ function sanitizedHtmlFrom(container: Element): string {
   return `<meta charset="utf-8">${container.innerHTML}`;
 }
 
+const TABLE_INTERIOR_TAGS = new Set(["TABLE", "THEAD", "TBODY", "TFOOT", "TR"]);
+
+/**
+ * A range spanning several cells or rows clones without its `table`, leaving
+ * nothing to serialize as a table. Rebuilds the shell from the table down to
+ * the range's common ancestor around the cloned fragment.
+ */
+function withTableShell(ancestor: Element | null, fragment: DocumentFragment): Node {
+  if (!ancestor || !TABLE_INTERIOR_TAGS.has(ancestor.tagName)) return fragment;
+  const table = ancestor.closest("table");
+  let shell: Node = fragment;
+  for (let element: Element | null = ancestor; element; element = element.parentElement) {
+    const clone = element.cloneNode(false);
+    clone.appendChild(shell);
+    shell = clone;
+    if (element === table) break;
+  }
+  return shell;
+}
+
 export function chatMarkdownClipboardPayload(
   selection: Selection,
+  tableFormat: TableCopyFormat = "markdown",
 ): MarkdownClipboardPayload | null {
   const texts: string[] = [];
   const htmls: string[] = [];
   for (let index = 0; index < selection.rangeCount; index += 1) {
     const range = selection.getRangeAt(index);
     if (range.collapsed) continue;
-    const container = document.createElement("div");
-    container.appendChild(range.cloneContents());
     const ancestor = range.commonAncestorContainer;
     const ancestorElement =
       ancestor.nodeType === Node.ELEMENT_NODE ? (ancestor as Element) : ancestor.parentElement;
+    const container = document.createElement("div");
+    container.appendChild(withTableShell(ancestorElement, range.cloneContents()));
     if (ancestorElement?.closest("pre")) {
       const text = range.toString();
       if (text) {
@@ -376,7 +503,7 @@ export function chatMarkdownClipboardPayload(
       }
       continue;
     }
-    const text = serializeRenderedMarkdownFragment(container);
+    const text = serializeRenderedMarkdownFragment(container, tableFormat);
     if (!text) continue;
     texts.push(text);
     htmls.push(sanitizedHtmlFrom(container));
diff --git a/packages/contracts/src/settings.ts b/packages/contracts/src/settings.ts
index 60d2aceed7cfc..b7aeb986f052c 100644
--- a/packages/contracts/src/settings.ts
+++ b/packages/contracts/src/settings.ts
@@ -50,6 +50,11 @@ export const TimestampFormat = Schema.Literals(["locale", "12-hour", "24-hour"])
 export type TimestampFormat = typeof TimestampFormat.Type;
 const DEFAULT_TIMESTAMP_FORMAT: TimestampFormat = "locale";
 
+/** How tables in chat markdown land on the clipboard when a whole message or selection is copied. */
+export const TableCopyFormat = Schema.Literals(["markdown", "tsv", "csv"]);
+export type TableCopyFormat = typeof TableCopyFormat.Type;
+const DEFAULT_TABLE_COPY_FORMAT: TableCopyFormat = "markdown";
+
 export const DiffLayout = Schema.Literals(["stacked", "split"]);
 export type DiffLayout = typeof DiffLayout.Type;
 const DEFAULT_DIFF_LAYOUT: DiffLayout = "stacked";
@@ -437,6 +442,9 @@ export const ClientSettingsSchema = Schema.Struct({
   timestampFormat: TimestampFormat.pipe(
     Schema.withDecodingDefault(Effect.succeed(DEFAULT_TIMESTAMP_FORMAT)),
   ),
+  tableCopyFormat: TableCopyFormat.pipe(
+    Schema.withDecodingDefault(Effect.succeed(DEFAULT_TABLE_COPY_FORMAT)),
+  ),
   snapShotEnabled: Schema.Boolean.pipe(Schema.withDecodingDefault(Effect.succeed(false))),
   snapShotIncludeAccessibility: Schema.Boolean.pipe(
     Schema.withDecodingDefault(Effect.succeed(true)),
@@ -1578,6 +1586,7 @@ export const ClientSettingsPatch = Schema.Struct({
   sidebarThreadSortOrder: Schema.optionalKey(SidebarThreadSortOrder),
   sidebarThreadPreviewCount: Schema.optionalKey(SidebarThreadPreviewCount),
   timestampFormat: Schema.optionalKey(TimestampFormat),
+  tableCopyFormat: Schema.optionalKey(TableCopyFormat),
   snapShotEnabled: Schema.optionalKey(Schema.Boolean),
   snapShotIncludeAccessibility: Schema.optionalKey(Schema.Boolean),
   snapShotShortcut: Schema.optionalKey(SnapShotShortcut),
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index e1ef8366399e0..c75b6bb459360 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -935,6 +935,9 @@ importers:
       remark-gfm:
         specifier: 'catalog:'
         version: 4.0.1
+      remark-parse:
+        specifier: 'catalog:'
+        version: 11.0.0
       tailwind-merge:
         specifier: ^3.4.0
         version: 3.6.0