diff --git a/.changeset/read-xlsx-spreadsheets.md b/.changeset/read-xlsx-spreadsheets.md
new file mode 100644
index 00000000000..0605b167ceb
--- /dev/null
+++ b/.changeset/read-xlsx-spreadsheets.md
@@ -0,0 +1,5 @@
+---
+"@kilocode/cli": patch
+---
+
+Support reading XLSX spreadsheets as labelled tabular text
diff --git a/bun.lock b/bun.lock
index 1abda6e1a39..2190f73907a 100644
--- a/bun.lock
+++ b/bun.lock
@@ -412,6 +412,7 @@
         "web-tree-sitter": "0.25.10",
         "which": "6.0.1",
         "xdg-basedir": "5.1.0",
+        "xlsx": "https://cdn.sheetjs.com/xlsx-0.20.3/xlsx-0.20.3.tgz",
         "yargs": "18.0.0",
         "zod": "catalog:",
         "zod-to-json-schema": "3.24.5",
@@ -4354,6 +4355,8 @@
 
     "xdg-basedir": ["xdg-basedir@5.1.0", "", {}, "sha512-GCPAHLvrIH13+c0SuacwvRYj2SxJXQ4kaVTT5xgL3kPrz56XxkF21IGhjSE1+W0aw7gpBWRGXLCPnPby6lSpmQ=="],
 
+    "xlsx": ["xlsx@https://cdn.sheetjs.com/xlsx-0.20.3/xlsx-0.20.3.tgz", { "bin": { "xlsx": "./bin/xlsx.njs" } }, "sha512-oLDq3jw7AcLqKWH2AhCpVTZl8mf6X2YReP+Neh0SJUzV/BdZYjth94tG5toiMB1PPrYtxOCfaoUCkvtuH+3AJA=="],
+
     "xml2js": ["xml2js@0.5.0", "", { "dependencies": { "sax": ">=0.6.0", "xmlbuilder": "~11.0.0" } }, "sha512-drPFnkQJik/O+uPKpqSgr22mpuFHqKdbS835iAQrUC73L2F5WkboIRd63ai/2Yg6I1jzifPFKH2NTK+cfglkIA=="],
 
     "xmlbuilder": ["xmlbuilder@11.0.1", "", {}, "sha512-fDlsI/kFEx7gLvbecc0/ohLG50fugQp8ryHzMTuW9vSa1GJ0XYWKnhsUx7oie3G98+r56aTQIUB4kht42R3JvA=="],
diff --git a/packages/opencode/package.json b/packages/opencode/package.json
index 89e79ca78b5..de0b7ccc97d 100644
--- a/packages/opencode/package.json
+++ b/packages/opencode/package.json
@@ -191,6 +191,7 @@
     "web-tree-sitter": "0.25.10",
     "which": "6.0.1",
     "xdg-basedir": "5.1.0",
+    "xlsx": "https://cdn.sheetjs.com/xlsx-0.20.3/xlsx-0.20.3.tgz",
     "yargs": "18.0.0",
     "zod": "catalog:",
     "zod-to-json-schema": "3.24.5"
diff --git a/packages/opencode/src/kilocode/tool/xlsx.ts b/packages/opencode/src/kilocode/tool/xlsx.ts
new file mode 100644
index 00000000000..95dc608c2df
--- /dev/null
+++ b/packages/opencode/src/kilocode/tool/xlsx.ts
@@ -0,0 +1,72 @@
+import path from "path"
+import { Readable } from "stream"
+import { read, utils, type CellObject, type WorkBook } from "xlsx"
+
+const ROW_LIMIT = 50_000
+
+export function is(filepath: string) {
+  return path.extname(filepath).toLowerCase() === ".xlsx"
+}
+
+export async function open(filepath: string) {
+  const bytes = new Uint8Array(await Bun.file(filepath).arrayBuffer())
+  if (bytes[0] !== 0x50 || bytes[1] !== 0x4b) {
+    throw new Error(`Cannot read spreadsheet file: ${filepath} is not a valid XLSX workbook`)
+  }
+
+  try {
+    const book = read(bytes, { type: "array", cellDates: true })
+    return Readable.from(lines(book))
+  } catch (err) {
+    const message = err instanceof Error ? err.message : String(err)
+    throw new Error(`Cannot read spreadsheet file: ${filepath}: ${message}`, { cause: err })
+  }
+}
+
+function cell(value: CellObject | undefined) {
+  if (!value) return ""
+  if (value.f) {
+    if (value.w !== undefined && value.w !== null) return value.w
+    if (value.v !== undefined && value.v !== null) return String(value.v)
+    return `[Formula: ${value.f}]`
+  }
+  if (value.v === undefined || value.v === null) return ""
+  if (value.t === "e") return `[Error: ${value.w ?? String(value.v)}]`
+  if (value.t === "d") return value.v instanceof Date ? value.v.toISOString().slice(0, 10) : String(value.v)
+  if (value.l?.Target) return `${value.w ?? String(value.v)} (${value.l.Target})`
+  return value.w ?? String(value.v)
+}
+
+function* lines(book: WorkBook) {
+  const sheets = book.SheetNames.filter((_, index) => {
+    const hidden = book.Workbook?.Sheets?.[index]?.Hidden
+    return hidden !== 1 && hidden !== 2
+  })
+  for (const [index, name] of sheets.entries()) {
+    if (index > 0) yield "\n"
+    yield `--- Sheet: ${name} ---\n`
+
+    const sheet = book.Sheets[name]
+    if (!sheet?.["!ref"]) continue
+    const range = utils.decode_range(sheet["!ref"])
+    const end = Math.min(range.e.r, ROW_LIMIT - 1)
+    const rows = new Map<number, Map<number, string>>()
+    for (const key of Object.keys(sheet)) {
+      if (key.startsWith("!")) continue
+      const pos = utils.decode_cell(key)
+      if (pos.r < range.s.r || pos.r > end || pos.c < range.s.c || pos.c > range.e.c) continue
+      const value = cell(sheet[key])
+      if (!value.trim()) continue
+      const row = rows.get(pos.r) ?? new Map<number, string>()
+      row.set(pos.c, value)
+      rows.set(pos.r, row)
+    }
+
+    for (const values of [...rows.entries()].sort((a, b) => a[0] - b[0]).map((entry) => entry[1])) {
+      const last = Math.max(...values.keys())
+      const row = Array.from({ length: last - range.s.c + 1 }, (_, col) => values.get(col + range.s.c) ?? "")
+      yield row.join("\t") + "\n"
+    }
+    if (range.e.r > end) yield `[... truncated at row ${ROW_LIMIT} ...]\n`
+  }
+}
diff --git a/packages/opencode/src/tool/read.ts b/packages/opencode/src/tool/read.ts
index 551e3744553..b5b5436a487 100644
--- a/packages/opencode/src/tool/read.ts
+++ b/packages/opencode/src/tool/read.ts
@@ -15,6 +15,7 @@ import { isPdfAttachment, sniffAttachmentMime } from "@/util/media"
 // kilocode_change start
 import * as Encoding from "../kilocode/encoding"
 import * as TextStream from "../kilocode/text-stream"
+import * as Xlsx from "../kilocode/tool/xlsx"
 // kilocode_change end
 
 const DEFAULT_READ_LIMIT = 2000
@@ -300,13 +301,18 @@ export const ReadTool = Tool.define(
         }
       }
 
-      if (isBinaryFile(filepath, sample)) {
+      // kilocode_change start - extract XLSX text before generic binary rejection
+      const xlsx = Xlsx.is(filepath)
+      const opts = { limit: params.limit ?? DEFAULT_READ_LIMIT, offset: params.offset || 1 }
+      const read = xlsx
+        ? () => Xlsx.open(filepath).then((stream) => readLines(stream, opts))
+        : () => lines(filepath, opts)
+      if (!xlsx && isBinaryFile(filepath, sample)) {
         return yield* Effect.fail(new Error(`Cannot read binary file: ${filepath}`))
       }
 
-      const file = yield* Effect.promise(() =>
-        lines(filepath, { limit: params.limit ?? DEFAULT_READ_LIMIT, offset: params.offset || 1 }),
-      )
+      const file = yield* Effect.promise(read)
+      // kilocode_change end
       if (file.count < file.offset && !(file.count === 0 && file.offset === 1)) {
         return yield* Effect.fail(
           new Error(`Offset ${file.offset} is out of range for this file (${file.count} lines)`),
diff --git a/packages/opencode/test/kilocode/read-xlsx.test.ts b/packages/opencode/test/kilocode/read-xlsx.test.ts
new file mode 100644
index 00000000000..1b358e73313
--- /dev/null
+++ b/packages/opencode/test/kilocode/read-xlsx.test.ts
@@ -0,0 +1,225 @@
+import { Cause, Effect, Exit, Layer } from "effect"
+import { describe, expect } from "bun:test"
+import path from "path"
+import { write, utils, type WorkBook, type WorkSheet } from "xlsx"
+import { TextReader, TextWriter, Uint8ArrayReader, Uint8ArrayWriter, ZipReader, ZipWriter } from "@zip.js/zip.js"
+import { Agent } from "../../src/agent/agent"
+import * as CrossSpawnSpawner from "@opencode-ai/core/cross-spawn-spawner"
+import { AppFileSystem } from "@opencode-ai/core/filesystem"
+import { LSP } from "../../src/lsp/lsp"
+import { Instruction } from "../../src/session/instruction"
+import { MessageID, SessionID } from "../../src/session/schema"
+import { ReadTool } from "../../src/tool/read"
+import { Tool } from "../../src/tool/tool"
+import { Truncate } from "../../src/tool/truncate"
+import { provideInstance, tmpdirScoped } from "../fixture/fixture"
+import { testEffect } from "../lib/effect"
+
+const ctx = {
+  sessionID: SessionID.make("ses_test"),
+  messageID: MessageID.make(""),
+  callID: "",
+  agent: "code",
+  abort: AbortSignal.any([]),
+  messages: [],
+  metadata: () => Effect.void,
+  ask: () => Effect.void,
+}
+
+const it = testEffect(
+  Layer.mergeAll(
+    Agent.defaultLayer,
+    AppFileSystem.defaultLayer,
+    CrossSpawnSpawner.defaultLayer,
+    Instruction.defaultLayer,
+    LSP.defaultLayer,
+    Truncate.defaultLayer,
+  ),
+)
+
+const run = Effect.fn("XlsxReadTest.run")(function* (
+  dir: string,
+  file: string,
+  opts: { limit?: number; offset?: number } = {},
+) {
+  const info = yield* ReadTool
+  const tool = yield* Tool.init(info)
+  return yield* provideInstance(dir)(tool.execute({ filePath: file, ...opts }, ctx))
+})
+
+const fail = Effect.fn("XlsxReadTest.fail")(function* (dir: string, file: string) {
+  const exit = yield* run(dir, file).pipe(Effect.exit)
+  if (Exit.isFailure(exit)) {
+    const err = Cause.squash(exit.cause)
+    return err instanceof Error ? err : new Error(String(err))
+  }
+  throw new Error("expected read to fail")
+})
+
+const put = Effect.fn("XlsxReadTest.put")(function* (file: string, bytes: Uint8Array | string) {
+  const fs = yield* AppFileSystem.Service
+  yield* fs.writeWithDirs(file, bytes)
+})
+
+function bytes(book: WorkBook) {
+  return new Uint8Array(write(book, { bookType: "xlsx", type: "buffer" }) as Uint8Array)
+}
+
+async function range(bytes: Uint8Array) {
+  const reader = new ZipReader(new Uint8ArrayReader(bytes))
+  const output = new ZipWriter(new Uint8ArrayWriter())
+  for (const entry of await reader.getEntries()) {
+    if (entry.directory) {
+      await output.add(entry.filename)
+      continue
+    }
+    if (entry.filename === "xl/worksheets/sheet1.xml") {
+      const xml = await entry.getData!(new TextWriter())
+      const sheet = xml
+        .replace(/ref="A1"/, 'ref="A1:XFD50001"')
+        .replace("</sheetData>", '<row r="50001"><c r="A50001" t="str"><v>last</v></c></row></sheetData>')
+      await output.add(entry.filename, new TextReader(sheet))
+      continue
+    }
+    await output.add(entry.filename, new Uint8ArrayReader(await entry.getData!(new Uint8ArrayWriter())))
+  }
+  await reader.close()
+  return output.close()
+}
+
+function book(sheet: WorkSheet, name = "Visible") {
+  const value = utils.book_new()
+  utils.book_append_sheet(value, sheet, name)
+  return value
+}
+
+describe("kilocode XLSX reads", () => {
+  it.live("extracts labelled formatted content from case-variant XLSX files", () =>
+    Effect.gen(function* () {
+      const dir = yield* tmpdirScoped()
+      const sheet: WorkSheet = {
+        A1: { t: "s", v: "Link", l: { Target: "https://kilo.ai" } },
+        B1: { t: "d", v: new Date("2026-05-29T00:00:00.000Z") },
+        C1: { t: "n", v: 42, f: "SUM(40,2)" },
+        D1: { t: "e", v: 0x07, w: "#DIV/0!" },
+        C2: { t: "n", f: "SUM(C1:C1)" },
+        A4: { t: "s", v: "After blank row" },
+        "!ref": "A1:D4",
+      }
+      const file = path.join(dir, "report.XLSX")
+      yield* put(file, bytes(book(sheet)))
+
+      const result = yield* run(dir, file)
+
+      expect(result.output).toContain("--- Sheet: Visible ---")
+      expect(result.output).toContain("Link (https://kilo.ai)")
+      expect(result.output).toContain("2026-05-29")
+      expect(result.output).toContain("42")
+      expect(result.output).toContain("[Formula: SUM(C1:C1)]")
+      expect(result.output).toContain("[Error: #DIV/0!]")
+      expect(result.output).toContain("After blank row")
+      expect(result.attachments).toBeUndefined()
+    }),
+  )
+
+  it.live("omits hidden and very-hidden worksheets", () =>
+    Effect.gen(function* () {
+      const dir = yield* tmpdirScoped()
+      const value = book(utils.aoa_to_sheet([["Visible content"]]))
+      utils.book_append_sheet(value, utils.aoa_to_sheet([["Hidden content"]]), "Hidden")
+      utils.book_append_sheet(value, utils.aoa_to_sheet([["Secret content"]]), "Secret")
+      value.Workbook = { Sheets: [{ Hidden: 0 }, { Hidden: 1 }, { Hidden: 2 }] }
+      const file = path.join(dir, "sheets.xlsx")
+      yield* put(file, bytes(value))
+
+      const result = yield* run(dir, file)
+
+      expect(result.output).toContain("Visible content")
+      expect(result.output).not.toContain("Hidden content")
+      expect(result.output).not.toContain("Secret content")
+    }),
+  )
+
+  it.live("caps worksheet extraction rows before ordinary read limits", () =>
+    Effect.gen(function* () {
+      const dir = yield* tmpdirScoped()
+      const sheet = utils.aoa_to_sheet(Array.from({ length: 50_001 }, (_, row) => [`row-${row + 1}`]))
+      const file = path.join(dir, "large.xlsx")
+      yield* put(file, bytes(book(sheet)))
+
+      const result = yield* run(dir, file, { offset: 49_999, limit: 4 })
+
+      expect(result.output).toContain("row-50000")
+      expect(result.output).not.toContain("row-50001")
+      expect(result.output).toContain("[... truncated at row 50000 ...]")
+    }),
+  )
+
+  it.live("applies ordinary read line limits to spreadsheet text", () =>
+    Effect.gen(function* () {
+      const dir = yield* tmpdirScoped()
+      const file = path.join(dir, "limited.xlsx")
+      yield* put(file, bytes(book(utils.aoa_to_sheet([["one"], ["two"], ["three"]]))))
+
+      const result = yield* run(dir, file, { limit: 2 })
+
+      expect(result.metadata.truncated).toBe(true)
+      expect(result.output).toContain("1: --- Sheet: Visible ---")
+      expect(result.output).toContain("2: one")
+      expect(result.output).not.toContain("3: two")
+    }),
+  )
+
+  it.live("does not traverse every blank cell in a sparse wide range", () =>
+    Effect.gen(function* () {
+      const dir = yield* tmpdirScoped()
+      const file = path.join(dir, "sparse.xlsx")
+      const source = bytes(book(utils.aoa_to_sheet([["first"]])))
+      yield* put(file, yield* Effect.promise(() => range(source)))
+
+      const result = yield* run(dir, file)
+
+      expect(result.output).toContain("--- Sheet: Visible ---")
+      expect(result.output).toContain("first")
+      expect(result.output).toContain("[... truncated at row 50000 ...]")
+    }),
+  )
+
+  it.live("fails clearly for invalid spreadsheet input", () =>
+    Effect.gen(function* () {
+      const dir = yield* tmpdirScoped()
+      const file = path.join(dir, "invalid.xlsx")
+      yield* put(file, "not an xlsx workbook")
+
+      const err = yield* fail(dir, file)
+
+      expect(err.message).toContain("Cannot read spreadsheet file")
+      expect(err.message).toContain("not a valid XLSX workbook")
+    }),
+  )
+
+  it.live("continues rejecting unsupported workbook formats as binary", () =>
+    Effect.gen(function* () {
+      const dir = yield* tmpdirScoped()
+      const file = path.join(dir, "legacy.xls")
+      yield* put(file, bytes(book(utils.aoa_to_sheet([["ignored"]]))))
+
+      const err = yield* fail(dir, file)
+
+      expect(err.message).toContain("Cannot read binary file")
+    }),
+  )
+
+  it.live("continues returning PDF files as native attachments", () =>
+    Effect.gen(function* () {
+      const dir = yield* tmpdirScoped()
+      const file = path.join(dir, "native.pdf")
+      yield* put(file, "%PDF-1.7\n")
+
+      const result = yield* run(dir, file)
+
+      expect(result.output).toBe("PDF read successfully")
+      expect(result.attachments?.[0].mime).toBe("application/pdf")
+    }),
+  )
+})