diff --git a/.github/workflows/format.yml b/.github/workflows/format.yml
new file mode 100644
index 00000000000..76afc4b4a7e
--- /dev/null
+++ b/.github/workflows/format.yml
@@ -0,0 +1,21 @@
+name: format
+
+on:
+  pull_request:
+    branches: [dev]
+  workflow_dispatch:
+
+jobs:
+  format:
+    runs-on: blacksmith-4vcpu-ubuntu-2404
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Bun
+        uses: ./.github/actions/setup-bun
+
+      - name: Check formatting
+        run: ./script/format.ts --check
+        env:
+          CI: true
diff --git a/packages/opencode/src/cli/cmd/storage.ts b/packages/opencode/src/cli/cmd/storage.ts
new file mode 100644
index 00000000000..8c833d52be2
--- /dev/null
+++ b/packages/opencode/src/cli/cmd/storage.ts
@@ -0,0 +1,88 @@
+import type { Argv } from "yargs"
+import { cmd } from "./cmd"
+import { bootstrap } from "../bootstrap"
+import { Storage } from "../../storage/storage"
+
+export const StorageCommand = cmd({
+  command: "storage",
+  describe: "manage storage",
+  builder: (yargs: Argv) => yargs.command(StorageRepairCommand).command(StorageRestoreCommand).demandCommand(),
+  async handler() {},
+})
+
+export const StorageRepairCommand = cmd({
+  command: "repair",
+  describe: "scan storage, quarantine invalid JSON and clean temp files",
+  builder: (yargs: Argv) =>
+    yargs
+      .option("dry-run", {
+        type: "boolean",
+        describe: "do not modify files, only report actions",
+        default: false,
+      })
+      .option("prefix", {
+        type: "array",
+        describe: "limit scan to a subpath prefix",
+      })
+      .option("max-files", {
+        type: "number",
+        describe: "maximum number of files to process",
+      })
+      .option("max-mib", {
+        type: "number",
+        describe: "maximum total megabytes to process",
+      })
+      .option("report", {
+        type: "string",
+        describe: "write a JSON report to the given path",
+      }),
+  handler: async (argv: any) => {
+    await bootstrap(process.cwd(), async () => {
+      const result = await Storage.repair({
+        dryRun: !!argv["dry-run"],
+        prefix: (argv.prefix as string[] | undefined)?.map(String),
+        maxFiles: argv["max-files"] ? Number(argv["max-files"]) : undefined,
+        maxMiB: argv["max-mib"] ? Number(argv["max-mib"]) : undefined,
+        reportPath: argv.report as string | undefined,
+      })
+      console.log(
+        JSON.stringify(
+          {
+            quarantined: result.quarantined,
+            tempRemoved: result.tempRemoved,
+            quarantineRoot: result.quarantineRoot,
+            skippedLocked: result.skippedLocked,
+            reportPath: result.reportPath,
+          },
+          null,
+          2,
+        ),
+      )
+    })
+  },
+})
+
+export const StorageRestoreCommand = cmd({
+  command: "restore <path>",
+  describe: "restore quarantined files back to storage",
+  builder: (yargs: Argv) =>
+    yargs
+      .positional("path", { describe: "path to a quarantined file or directory", type: "string" })
+      .option("dry-run", { type: "boolean", describe: "do not move files, only report", default: false }),
+  handler: async (argv: any) => {
+    await bootstrap(process.cwd(), async () => {
+      const result = await Storage.restore({ path: argv.path as string, dryRun: !!argv["dry-run"] })
+      console.log(
+        JSON.stringify(
+          {
+            restored: result.restored,
+            skippedLocked: result.skippedLocked,
+            files: result.files,
+          },
+          null,
+          2,
+        ),
+      )
+    })
+  },
+})
diff --git a/packages/opencode/src/index.ts b/packages/opencode/src/index.ts
index 6099443e798..e268559c808 100644
--- a/packages/opencode/src/index.ts
+++ b/packages/opencode/src/index.ts
@@ -27,6 +27,7 @@ import { EOL } from "os"
 import { WebCommand } from "./cli/cmd/web"
 import { PrCommand } from "./cli/cmd/pr"
 import { SessionCommand } from "./cli/cmd/session"
+import { StorageCommand } from "./cli/cmd/storage"
 
 process.on("unhandledRejection", (e) => {
   Log.Default.error("rejection", {
@@ -99,6 +100,7 @@ const cli = yargs(hideBin(process.argv))
   .command(GithubCommand)
   .command(PrCommand)
   .command(SessionCommand)
+  .command(StorageCommand)
   .fail((msg, err) => {
     if (
       msg?.startsWith("Unknown argument") ||
diff --git a/packages/opencode/src/storage/storage.ts b/packages/opencode/src/storage/storage.ts
index 8b4042ea13f..70d84903e03 100644
--- a/packages/opencode/src/storage/storage.ts
+++ b/packages/opencode/src/storage/storage.ts
@@ -1,6 +1,7 @@
 import { Log } from "../util/log"
 import path from "path"
 import fs from "fs/promises"
+import * as nodefs from "fs"
 import { Global } from "../global"
 import { lazy } from "../util/lazy"
 import { Lock } from "../util/lock"
@@ -20,6 +21,13 @@ export namespace Storage {
     }),
   )
 
+  export const DiskFullError = NamedError.create(
+    "DiskFullError",
+    z.object({
+      message: z.string(),
+    }),
+  )
+
   const MIGRATIONS: Migration[] = [
     async (dir) => {
       const project = path.resolve(dir, "../project")
@@ -142,6 +150,7 @@ export namespace Storage {
 
   const state = lazy(async () => {
     const dir = path.join(Global.Path.data, "storage")
+    await fs.mkdir(dir, { recursive: true }).catch(() => {})
     const migration = await Bun.file(path.join(dir, "migration"))
       .json()
       .then((x) => parseInt(x))
@@ -182,7 +191,7 @@ export namespace Storage {
       using _ = await Lock.write(target)
       const content = await Bun.file(target).json()
       fn(content)
-      await Bun.write(target, JSON.stringify(content, null, 2))
+      await atomicWrite(target, JSON.stringify(content, null, 2))
       return content as T
     })
   }
@@ -192,7 +201,7 @@ export namespace Storage {
     const target = path.join(dir, ...key) + ".json"
     return withErrorHandling(async () => {
       using _ = await Lock.write(target)
-      await Bun.write(target, JSON.stringify(content, null, 2))
+      await atomicWrite(target, JSON.stringify(content, null, 2))
     })
   }
 
@@ -203,6 +212,9 @@ export namespace Storage {
       if (errnoException.code === "ENOENT") {
         throw new NotFoundError({ message: `Resource not found: ${errnoException.path}` })
       }
+      if (errnoException.code === "ENOSPC") {
+        throw new DiskFullError({ message: `No space left on device while writing storage: ${errnoException.path}` })
+      }
       throw e
     })
   }
@@ -216,11 +228,205 @@ export namespace Storage {
           cwd: path.join(dir, ...prefix),
           onlyFiles: true,
         }),
-      ).then((results) => results.map((x) => [...prefix, ...x.slice(0, -5).split(path.sep)]))
+      ).then((results) => (results as string[]).map((x) => [...prefix, ...x.slice(0, -5).split(path.sep)]))
       result.sort()
       return result
     } catch {
       return []
     }
   }
+
+  async function atomicWrite(target: string, data: string) {
+    const dir = path.dirname(target)
+    await fs.mkdir(dir, { recursive: true })
+    const tmp = path.join(
+      dir,
+      `.oc-${path.basename(target)}.${process.pid}.${Date.now()}.tmp`,
+    )
+    const fh = await fs.open(tmp, "w")
+    try {
+      await fh.writeFile(data)
+      const syncFn = (fh as any).sync as (() => Promise<void>) | undefined
+      if (typeof syncFn === "function") {
+        await syncFn.call(fh)
+      } else {
+        const fd = (fh as any).fd as number | undefined
+        if (typeof fd === "number") {
+          await new Promise<void>((resolve, reject) => nodefs.fsync(fd, (err) => (err ? reject(err) : resolve())))
+        }
+      }
+    } finally {
+      await fh.close().catch(() => {})
+    }
+    try {
+      await fs.rename(tmp, target)
+      const dirFh = await fs.open(dir, "r").catch(() => null as any)
+      try {
+        const dirSync = (dirFh as any)?.sync as (() => Promise<void>) | undefined
+        if (typeof dirSync === "function") await dirSync.call(dirFh)
+        else {
+          const dfd = (dirFh as any)?.fd as number | undefined
+          if (typeof dfd === "number") {
+            await new Promise<void>((resolve, reject) => nodefs.fsync(dfd, (err) => (err ? reject(err) : resolve())))
+          }
+        }
+      } finally {
+        await dirFh?.close?.().catch?.(() => {})
+      }
+    } catch (e) {
+      await fs.rm(tmp, { force: true }).catch(() => {})
+      throw e
+    }
+  }
+
+  export async function repair(options?: {
+    dryRun?: boolean
+    prefix?: string[]
+    maxFiles?: number
+    maxMiB?: number
+    reportPath?: string
+  }) {
+    const dir = await state().then((x) => x.dir)
+    const ts = Date.now()
+    const quarantineRoot = path.join(dir, "quarantine", String(ts))
+    const dryRun = !!options?.dryRun
+    const base = options?.prefix?.length ? path.join(dir, ...options.prefix) : dir
+    const maxFiles = options?.maxFiles && options.maxFiles > 0 ? options.maxFiles : Infinity
+    const maxBytes = options?.maxMiB && options.maxMiB > 0 ? Math.floor(options.maxMiB * 1024 * 1024) : Infinity
+
+    let quarantined = 0
+    let tempRemoved = 0
+    let skippedLocked = 0
+    let processedFiles = 0
+    let processedBytes = 0
+    const report: { action: string; from: string; to?: string; reason?: string }[] = []
+
+    if (!dryRun) await fs.mkdir(quarantineRoot, { recursive: true }).catch(() => {})
+
+    for await (const file of new Bun.Glob("**/*.json").scan({ cwd: base, absolute: true })) {
+      if (processedFiles >= maxFiles || processedBytes >= maxBytes) break
+      const stat = await fs.stat(file).catch(() => null as any)
+      const size = stat?.size ?? 0
+      if (processedBytes + size > maxBytes) break
+      processedFiles++
+      processedBytes += size
+      try {
+        await Bun.file(file).json()
+      } catch {
+        const lock = Lock.tryWrite(file)
+        if (!lock) {
+          skippedLocked++
+          report.push({ action: "skip", from: file, reason: "locked" })
+          continue
+        }
+        try {
+          const rel = path.relative(dir, file)
+          const dest = path.join(quarantineRoot, rel)
+          report.push({ action: dryRun ? "would-move" : "move", from: file, to: dest, reason: "invalid-json" })
+          if (!dryRun) {
+            await fs.mkdir(path.dirname(dest), { recursive: true })
+            await fs.rename(file, dest).catch(async () => {
+              const content = await Bun.file(file).arrayBuffer().catch(() => new ArrayBuffer(0))
+              await Bun.write(dest, new Uint8Array(content))
+              await fs.rm(file, { force: true }).catch(() => {})
+            })
+          }
+          quarantined++
+        } finally {
+          ;(lock as any)?.[Symbol.dispose]?.()
+        }
+      }
+    }
+
+    const walk = async function* (p: string): AsyncGenerator<string> {
+      const s = await fs.stat(p).catch(() => null as any)
+      if (!s) return
+      if (s.isDirectory()) {
+        for (const entry of await fs.readdir(p).catch(() => [] as string[])) {
+          yield* walk(path.join(p, entry))
+        }
+        return
+      }
+      yield p
+    }
+
+    for await (const file of walk(base)) {
+      const baseName = path.basename(file)
+      if (baseName.startsWith(".oc-") && baseName.endsWith(".tmp")) {
+        report.push({ action: dryRun ? "would-remove" : "remove", from: file, reason: "leftover-temp" })
+        if (!dryRun) await fs.rm(file, { force: true }).catch(() => {})
+        tempRemoved++
+      }
+    }
+
+    const finalReportPath = options?.reportPath || path.join(quarantineRoot, "repair-report.json")
+    await fs.mkdir(path.dirname(finalReportPath), { recursive: true }).catch(() => {})
+    await Bun.write(
+      finalReportPath,
+      JSON.stringify(
+        {
+          time: ts,
+          base,
+          quarantined,
+          tempRemoved,
+          skippedLocked,
+          processedFiles,
+          processedBytes,
+          entries: report,
+        },
+        null,
+        2,
+      ),
+    )
+
+    log.info("storage.repair complete", { quarantined, tempRemoved, skippedLocked })
+    return { quarantined, tempRemoved, skippedLocked, quarantineRoot, reportPath: finalReportPath }
+  }
+
+  export async function restore(input: { path: string; dryRun?: boolean }) {
+    const dir = await state().then((x) => x.dir)
+    const abs = path.resolve(input.path)
+    const parts = abs.split(path.sep)
+    const qIndex = parts.lastIndexOf("quarantine")
+    if (qIndex < 0 || qIndex + 1 >= parts.length) return { restored: 0, skippedLocked: 0 }
+    const qRoot = parts.slice(0, qIndex + 2).join(path.sep)
+    const restoredFiles: string[] = []
+    let restored = 0
+    let skippedLocked = 0
+
+    const walker = async function* (p: string): AsyncGenerator<string> {
+      const s = await fs.stat(p)
+      if (s.isDirectory()) {
+        for await (const item of await fs.readdir(p)) yield* walker(path.join(p, item))
+        return
+      }
+      yield p
+    }
+
+    for await (const src of walker(abs)) {
+      const rel = path.relative(qRoot, src)
+      if (rel.startsWith("..")) continue
+      const dest = path.join(dir, rel)
+      const lock = Lock.tryWrite(dest)
+      if (!lock) {
+        skippedLocked++
+        continue
+      }
+      try {
+        await fs.mkdir(path.dirname(dest), { recursive: true })
+        if (!input.dryRun) await fs.rename(src, dest).catch(async () => {
+          const content = await Bun.file(src).arrayBuffer().catch(() => new ArrayBuffer(0))
+          await Bun.write(dest, new Uint8Array(content))
+          await fs.rm(src, { force: true }).catch(() => {})
+        })
+        restored++
+        restoredFiles.push(dest)
+      } finally {
+        ;(lock as any)?.[Symbol.dispose]?.()
+      }
+    }
+
+    log.info("storage.restore complete", { restored, skippedLocked })
+    return { restored, skippedLocked, files: restoredFiles }
+  }
 }
diff --git a/packages/opencode/src/util/lock.ts b/packages/opencode/src/util/lock.ts
index 3aea64394f8..eb02a745afb 100644
--- a/packages/opencode/src/util/lock.ts
+++ b/packages/opencode/src/util/lock.ts
@@ -95,4 +95,18 @@ export namespace Lock {
       }
     })
   }
+
+  export function tryWrite(key: string): Disposable | null {
+    const lock = get(key)
+    if (!lock.writer && lock.readers === 0) {
+      lock.writer = true
+      return {
+        [Symbol.dispose]: () => {
+          lock.writer = false
+          process(key)
+        },
+      }
+    }
+    return null
+  }
 }
diff --git a/packages/opencode/test/storage/repair.test.ts b/packages/opencode/test/storage/repair.test.ts
new file mode 100644
index 00000000000..2b1ec982185
--- /dev/null
+++ b/packages/opencode/test/storage/repair.test.ts
@@ -0,0 +1,72 @@
+import { describe, expect, test } from "bun:test"
+import path from "path"
+import fs from "fs/promises"
+import { Storage } from "../../src/storage/storage"
+import { Global } from "../../src/global"
+
+function storageDir() {
+  return path.join(Global.Path.data, "storage")
+}
+
+describe("storage.repair", () => {
+  test("quarantines invalid JSON files and removes temp files", async () => {
+    const dir = storageDir()
+
+    const badFile = path.join(dir, "test", "invalid", "bad.json")
+    await fs.mkdir(path.dirname(badFile), { recursive: true })
+    await fs.writeFile(badFile, "{invalid")
+
+    const tmpLeftover = path.join(dir, "leftovers", `.oc-foo.json.${process.pid}.${Date.now()}.tmp`)
+    await fs.mkdir(path.dirname(tmpLeftover), { recursive: true })
+    await fs.writeFile(tmpLeftover, "tmp")
+
+    const result = await Storage.repair()
+
+    expect(result.quarantined).toBeGreaterThanOrEqual(1)
+    expect(result.tempRemoved).toBeGreaterThanOrEqual(1)
+
+    await expect(fs.access(badFile)).rejects.toBeDefined()
+    await expect(fs.access(tmpLeftover)).rejects.toBeDefined()
+
+    const quarantinedBad = path.join(result.quarantineRoot, "test", "invalid", "bad.json")
+    const stat = await fs.stat(quarantinedBad)
+    expect(stat.isFile()).toBe(true)
+
+    const report = JSON.parse(await Bun.file(result.reportPath!).text())
+    expect(Array.isArray(report.entries)).toBe(true)
+  })
+
+  test("write/read roundtrip remains valid", async () => {
+    const key = ["roundtrip", "item"]
+    const content = { a: 1 }
+    await Storage.write(key, content)
+    const out = await Storage.read<typeof content>(key)
+    expect(out).toEqual(content)
+  })
+
+  test("repair dry-run reports but does not modify", async () => {
+    const dir = storageDir()
+    const badFile = path.join(dir, "test", "dryrun", "bad.json")
+    await fs.mkdir(path.dirname(badFile), { recursive: true })
+    await fs.writeFile(badFile, "{invalid")
+
+    const result = await Storage.repair({ dryRun: true })
+    expect(result.quarantined).toBeGreaterThanOrEqual(1)
+    await expect(fs.stat(badFile)).resolves.toBeDefined()
+  })
+
+  test("restore moves back quarantined files", async () => {
+    const dir = storageDir()
+    const badFile = path.join(dir, "test", "restore", "bad.json")
+    await fs.mkdir(path.dirname(badFile), { recursive: true })
+    await fs.writeFile(badFile, "{invalid")
+
+    const r = await Storage.repair()
+    const quarantinedBad = path.join(r.quarantineRoot, "test", "restore", "bad.json")
+    await expect(fs.stat(quarantinedBad)).resolves.toBeDefined()
+
+    const restored = await Storage.restore({ path: r.quarantineRoot })
+    expect(restored.restored).toBeGreaterThanOrEqual(1)
+    await expect(fs.stat(path.join(dir, "test", "restore", "bad.json"))).resolves.toBeDefined()
+  })
+})
diff --git a/packages/opencode/tsconfig.json b/packages/opencode/tsconfig.json
index 9067d84fd6a..7159b0f3f8f 100644
--- a/packages/opencode/tsconfig.json
+++ b/packages/opencode/tsconfig.json
@@ -2,6 +2,7 @@
   "$schema": "https://json.schemastore.org/tsconfig",
   "extends": "@tsconfig/bun/tsconfig.json",
   "compilerOptions": {
+    "moduleResolution": "bundler",
     "jsx": "preserve",
     "jsxImportSource": "@opentui/solid",
     "lib": ["ESNext", "DOM", "DOM.Iterable"],
diff --git a/script/format.ts b/script/format.ts
index 996de9ad04a..b527835e8bd 100755
--- a/script/format.ts
+++ b/script/format.ts
@@ -2,4 +2,6 @@
 
 import { $ } from "bun"
 
-await $`bun run prettier --ignore-unknown --write .`
+const check = Bun.argv.includes("--check")
+
+await $`bun run prettier --ignore-unknown ${check ? "--check" : "--write"} .`