diff --git a/docs/config-catalog.md b/docs/config-catalog.md
index 5d8ba2d088..3ba3523be9 100644
--- a/docs/config-catalog.md
+++ b/docs/config-catalog.md
@@ -181,7 +181,7 @@ export interface Config extends LocalConfig {
 
 Depends on: [`LocalConfig`](#deepseek-aidsh-bash-local) · [`SandboxMode`](core-data-structures/sandbox.md)
 
-Source: [`packages/bash/bash-sandbox/src/index.ts:26`](../packages/bash/bash-sandbox/src/index.ts)
+Source: [`packages/bash/bash-sandbox/src/index.ts:27`](../packages/bash/bash-sandbox/src/index.ts)
 
 ## `@deepseek-ai/dsh-code-runtime-worker`
 
@@ -574,7 +574,7 @@ export interface Config {
 }
 ```
 
-Source: [`packages/sandbox/sandbox-local/src/index.ts:20`](../packages/sandbox/sandbox-local/src/index.ts)
+Source: [`packages/sandbox/sandbox-local/src/index.ts:19`](../packages/sandbox/sandbox-local/src/index.ts)
 
 ## `@deepseek-ai/dsh-session-persistence-jsonl`
 
diff --git a/packages/bash/bash-sandbox/README.md b/packages/bash/bash-sandbox/README.md
index bc083ae138..347aefb679 100644
--- a/packages/bash/bash-sandbox/README.md
+++ b/packages/bash/bash-sandbox/README.md
@@ -2,6 +2,8 @@
 
 Sandbox-consuming implementation of the [`@deepseek-ai/dsh-bash`](../bash/) executor seam. Load it **instead of** `@deepseek-ai/dsh-bash-local`, together with a [`ctx.sandbox`](../../sandbox/sandbox/) provider (e.g. [`@deepseek-ai/dsh-sandbox-local`](../../sandbox/sandbox-local/)) — no alternate tool plugin is needed; `dsh-tool-bash` detects the executor's `sandboxMode` capability and adds the escalation fields.
 
+The package root exports the default and named `SandboxBashExecutor` plugin plus its `Config`; quoting and result-classification helpers stay internal.
+
 Every command is confined by handing the provider the exact `['bash', '-c', command]` argv this executor is about to spawn and spawning the returned (wrapped) argv instead. WHICH platform runner confines it — and whether one is usable at all (fail closed with a structured `SANDBOX_UNAVAILABLE` error, never a silent unconfined run) — is the provider's concern; this package owns the bash side only.
 
 | Mode | File effects |
diff --git a/packages/bash/bash-sandbox/src/helpers.ts b/packages/bash/bash-sandbox/src/helpers.ts
new file mode 100644
index 0000000000..a98f47216e
--- /dev/null
+++ b/packages/bash/bash-sandbox/src/helpers.ts
@@ -0,0 +1,49 @@
+/**
+ * Internal shell-quoting and sandbox-result classification helpers.
+ *
+ * @module @deepseek-ai/dsh-bash-sandbox/helpers
+ */
+
+import type { BashRunResult } from '@deepseek-ai/dsh-bash'
+
+/**
+ * Quote one string as a single-quoted POSIX shell word.
+ * @param text - raw argv element to preserve through the outer shell parse.
+ * @returns the quoted shell word.
+ */
+export function shellQuote(text: string): string {
+  return `'${text.replaceAll("'", String.raw`'\''`)}'`
+}
+
+/**
+ * Classify a failed run against the selected backend's denial dialect.
+ * @param result - settled foreground run.
+ * @param signatures - case-insensitive denial substrings from the active wrap.
+ * @returns whether the failed run matches that denial dialect.
+ */
+export function classifyDenial(result: BashRunResult, signatures: readonly string[]): boolean {
+  return matchesSignature(result.exitCode, result.stderr.text, signatures)
+}
+
+/**
+ * Classify a failed run against the selected backend's runner-failure dialect.
+ * @param result - settled foreground run.
+ * @param signatures - case-insensitive runner-failure substrings from the active wrap.
+ * @returns whether the failed run matches that runner-failure dialect.
+ */
+export function classifyRunnerFailure(result: BashRunResult, signatures: readonly string[]): boolean {
+  return matchesSignature(result.exitCode, result.stderr.text, signatures)
+}
+
+/**
+ * Match a non-zero exit against case-insensitive stderr signatures.
+ * @param exitCode - process exit code; null means signal termination.
+ * @param stderr - collected stderr text.
+ * @param signatures - substrings identifying the selected backend's dialect.
+ * @returns whether this is a non-zero exit whose stderr matches a signature.
+ */
+export function matchesSignature(exitCode: number | null, stderr: string, signatures: readonly string[]): boolean {
+  if (exitCode === null || exitCode === 0) return false
+  const lowered = stderr.toLowerCase()
+  return signatures.some(signature => lowered.includes(signature.toLowerCase()))
+}
diff --git a/packages/bash/bash-sandbox/src/index.ts b/packages/bash/bash-sandbox/src/index.ts
index 704cd4604b..124f6b6a9f 100644
--- a/packages/bash/bash-sandbox/src/index.ts
+++ b/packages/bash/bash-sandbox/src/index.ts
@@ -15,6 +15,7 @@ import { SandboxUnavailableError } from '@deepseek-ai/dsh-sandbox'
 import type { ConfinedSandboxMode, SandboxEnforcement, SandboxMode } from '@deepseek-ai/dsh-sandbox'
 import { LocalBashExecutor } from '@deepseek-ai/dsh-bash-local'
 import type { Config as LocalConfig } from '@deepseek-ai/dsh-bash-local'
+import { classifyDenial, classifyRunnerFailure, matchesSignature, shellQuote } from './helpers.ts'
 
 /**
  * Plugin config: the local executor's knobs plus the sandbox policy. All
@@ -33,52 +34,6 @@ export interface Config extends LocalConfig {
   workspaceRoot?: string
 }
 
-/**
- * Quote one string as a single-quoted POSIX shell word (embedded single
- * quotes become `'\''`), so a wrapped argv element survives the outer
- * `bash -c` re-parse byte-for-byte.
- * @param text - the raw argv element to quote.
- * @returns the single-quoted shell word.
- */
-export function shellQuote(text: string): string {
-  return `'${text.replaceAll("'", String.raw`'\''`)}'`
-}
-
-/**
- * Conservatively classify a nonzero, non-signal run using only the selected
- * backend's denial signatures. Text inference may miss a denial or match
- * unrelated stderr in that dialect; it never uses another backend's terms.
- * @param result - the settled foreground run to classify.
- * @param signatures - the active wrap's denial dialect, case-insensitive stderr substrings.
- * @returns whether the run's failure reads as a sandbox denial.
- */
-export function classifyDenial(result: BashRunResult, signatures: readonly string[]): boolean {
-  return matchesSignature(result.exitCode, result.stderr.text, signatures)
-}
-
-/**
- * Classify a nonzero run using the selected backend's runner-failure
- * signatures. Callers check this before denial because runner diagnostics may
- * contain denial words; the command did not run.
- * @param result - the settled foreground run to classify.
- * @param signatures - the active wrap's runner-failure signatures,
- *   case-insensitive stderr substrings.
- * @returns whether the run's failure reads as the runner itself failing.
- */
-export function classifyRunnerFailure(result: BashRunResult, signatures: readonly string[]): boolean {
-  return matchesSignature(result.exitCode, result.stderr.text, signatures)
-}
-
-/**
- * Shared classifier for failed runs. Signatures are case-insensitive and may
- * include runtime values such as an executable path.
- */
-function matchesSignature(exitCode: number | null, stderr: string, signatures: readonly string[]): boolean {
-  if (exitCode === null || exitCode === 0) return false
-  const lowered = stderr.toLowerCase()
-  return signatures.some(signature => lowered.includes(signature.toLowerCase()))
-}
-
 /**
  * Registers as `ctx.bash` in place of the local executor and requires a
  * `ctx.sandbox` provider; the tool layer is unchanged. The configured mode is
diff --git a/packages/bash/bash-sandbox/tests/bwrap.e2e.ts b/packages/bash/bash-sandbox/tests/bwrap.e2e.ts
index 9a5da8fdb4..237619ae06 100644
--- a/packages/bash/bash-sandbox/tests/bwrap.e2e.ts
+++ b/packages/bash/bash-sandbox/tests/bwrap.e2e.ts
@@ -5,7 +5,8 @@ import { homedir } from 'node:os'
 import { join } from 'node:path'
 import { afterEach, describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
-import { bwrapProfileArgs, LocalSandboxProvider } from '@deepseek-ai/dsh-sandbox-local'
+import { LocalSandboxProvider } from '@deepseek-ai/dsh-sandbox-local'
+import { bwrapProfileArgs } from '@deepseek-ai/dsh-sandbox-local/src/profiles.ts'
 import { SandboxBashExecutor } from '@deepseek-ai/dsh-bash-sandbox'
 
 /**
diff --git a/packages/bash/bash-sandbox/tests/sandbox.spec.ts b/packages/bash/bash-sandbox/tests/sandbox.spec.ts
index c8ecc73886..619bc05151 100644
--- a/packages/bash/bash-sandbox/tests/sandbox.spec.ts
+++ b/packages/bash/bash-sandbox/tests/sandbox.spec.ts
@@ -13,7 +13,8 @@ import { Context } from 'cordis'
 import type { BashRunResult, CollectedOutput } from '@deepseek-ai/dsh-bash'
 import { SANDBOX_UNAVAILABLE, SandboxProvider, SandboxUnavailableError } from '@deepseek-ai/dsh-sandbox'
 import type { ConfinedArgv, SandboxPolicy } from '@deepseek-ai/dsh-sandbox'
-import { classifyDenial, classifyRunnerFailure, SandboxBashExecutor, shellQuote } from '@deepseek-ai/dsh-bash-sandbox'
+import { SandboxBashExecutor } from '@deepseek-ai/dsh-bash-sandbox'
+import { classifyDenial, classifyRunnerFailure, shellQuote } from '../src/helpers.ts'
 import type { Config } from '@deepseek-ai/dsh-bash-sandbox'
 
 const spillDir = mkdtempSync(join(tmpdir(), 'dsh-bash-sandbox-spec-'))
diff --git a/packages/bash/bash-sandbox/tests/seatbelt.e2e.ts b/packages/bash/bash-sandbox/tests/seatbelt.e2e.ts
index 7cc58202fc..cc3703d742 100644
--- a/packages/bash/bash-sandbox/tests/seatbelt.e2e.ts
+++ b/packages/bash/bash-sandbox/tests/seatbelt.e2e.ts
@@ -5,7 +5,8 @@ import { homedir } from 'node:os'
 import { join } from 'node:path'
 import { afterEach, describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
-import { LocalSandboxProvider, seatbeltProfileArgs } from '@deepseek-ai/dsh-sandbox-local'
+import { LocalSandboxProvider } from '@deepseek-ai/dsh-sandbox-local'
+import { seatbeltProfileArgs } from '@deepseek-ai/dsh-sandbox-local/src/profiles.ts'
 import { SandboxBashExecutor } from '@deepseek-ai/dsh-bash-sandbox'
 
 /**
diff --git a/packages/sandbox/sandbox-local/README.md b/packages/sandbox/sandbox-local/README.md
index fa0ff7257f..cbd765bbf9 100644
--- a/packages/sandbox/sandbox-local/README.md
+++ b/packages/sandbox/sandbox-local/README.md
@@ -2,6 +2,8 @@
 
 Local implementation of the [`dsh-sandbox`](../sandbox/) seam. It selects and caches one platform runner: Linux prefers a working `bwrap` then Landlock; macOS uses Seatbelt. Multiple candidates are probed in order, while a sole candidate is selected directly.
 
+The package root exports the default and named `LocalSandboxProvider` plugin, `Config`, and its public test-injection seam; platform profile builders stay internal.
+
 Unsupported platforms and unusable runners fail closed with `SANDBOX_UNAVAILABLE`; execution never silently falls through unconfined. Each wrap carries runner-failure signatures so consumers can distinguish a broken sandbox from a command failure. The [sandbox RFC](../../../docs/rfc/implemented/feature/2026-07-06-sandbox.md) owns selection rationale and profile differences.
 
 Policy is per call; the provider stores only the mechanism and cached runner verdict. Each wrap reports enforcement completeness plus backend-specific denial and runner-failure signatures. `runnerCommand` is an operator assertion of a bwrap-shaped runner and skips probes, but missing or unexecutable commands still fail closed at execution. Because its mechanism is unknown, it carries both Linux denial dialects. `probeTimeoutMs` bounds functional probes. The [sandbox RFC](../../../docs/rfc/implemented/feature/2026-07-06-sandbox.md) owns selection and failure semantics.
diff --git a/packages/sandbox/sandbox-local/src/index.ts b/packages/sandbox/sandbox-local/src/index.ts
index cc464eb5c4..98dc86d23e 100644
--- a/packages/sandbox/sandbox-local/src/index.ts
+++ b/packages/sandbox/sandbox-local/src/index.ts
@@ -7,14 +7,13 @@
  */
 
 import { spawnSync } from 'node:child_process'
-import { realpathSync } from 'node:fs'
-import { tmpdir } from 'node:os'
-import { grantArgs as landlockGrantArgs, LAUNCHER_BIN, launcherPath as landlockLauncherPath, probe as defaultProbeLandlock } from 'node-addon-landlock-run'
+import { LAUNCHER_BIN, launcherPath as landlockLauncherPath, probe as defaultProbeLandlock } from 'node-addon-landlock-run'
 import { Context } from 'cordis'
 import z from 'schemastery'
 import { assertNever } from '@deepseek-ai/dsh-llm'
 import { SandboxProvider, SandboxUnavailableError } from '@deepseek-ai/dsh-sandbox'
 import type { ConfinedArgv, ConfinedSandboxMode, SandboxEnforcement, SandboxPolicy } from '@deepseek-ai/dsh-sandbox'
+import { bwrapProfileArgs, landlockProfileArgs, seatbeltProfileArgs } from './profiles.ts'
 
 /** Plugin config. All optional — `static Config` supplies the defaults. */
 export interface Config {
@@ -38,77 +37,6 @@ export interface Config {
   probeTimeoutMs?: number
 }
 
-/**
- * Build a bwrap profile: the host is read-only with fresh `/dev` and `/proc`;
- * workspace-write overlays writable temp and workspace mounts. PID and network
- * isolation are intentionally outside the file-effect policy.
- *
- * @param policy - the file-effect policy to express as bwrap arguments.
- * @returns the bwrap profile arguments (before the trailing `--` + argv).
- */
-export function bwrapProfileArgs(policy: SandboxPolicy): string[] {
-  const args = ['--ro-bind', '/', '/', '--dev', '/dev', '--proc', '/proc', '--die-with-parent']
-  if (policy.mode === 'workspace-write') {
-    args.push('--tmpfs', '/tmp')
-    args.push('--bind', policy.workspaceRoot, policy.workspaceRoot)
-  }
-  return args
-}
-
-/**
- * Build Landlock grants for the same file policy without synthetic mounts.
- * Read-only grants only `/dev/null` for writes; workspace-write also grants the
- * host temp root and workspace.
- *
- * @param policy - the file-effect policy to express as launcher grants.
- * @returns the launcher grant arguments (before `--` + argv).
- */
-export function landlockProfileArgs(policy: SandboxPolicy): string[] {
-  const readWrite = ['/dev/null']
-  if (policy.mode === 'workspace-write') {
-    readWrite.push('/tmp', policy.workspaceRoot)
-  }
-  return landlockGrantArgs({ readOnly: ['/'], readWrite })
-}
-
-/**
- * Resolve a granted root to the path the kernel actually sees. Seatbelt path
- * filters match the CANONICAL path (symlinks resolved), and the roots this
- * profile grants are symlinked on every macOS: `/tmp` is `/private/tmp` and
- * the user temp dir lives under `/var` → `/private/var` — an as-spelled
- * grant would match nothing.
- */
-function canonicalPath(path: string): string {
-  try {
-    return realpathSync(path)
-  } catch {
-    // An unresolved grant matches nothing until the named path exists; keep its spelling.
-    return path
-  }
-}
-
-/** Quote one path as an SBPL string literal (backslashes and double quotes escaped). */
-function sbplString(path: string): string {
-  return `"${path.replaceAll('\\', String.raw`\\`).replaceAll('"', String.raw`\"`)}"`
-}
-
-/**
- * Build a Seatbelt profile that denies file writes then allows `/dev/null` and,
- * for workspace-write, the canonical workspace, host temp, and per-user macOS
- * temp roots. Network and process visibility remain unrestricted.
- *
- * @param policy - the file-effect policy to express as an SBPL profile.
- * @returns the `sandbox-exec` arguments (`-p` + profile, before `--` + argv).
- */
-export function seatbeltProfileArgs(policy: SandboxPolicy): string[] {
-  const forms = ['(version 1)', '(allow default)', '(deny file-write*)', `(allow file-write* (literal ${sbplString('/dev/null')}))`]
-  if (policy.mode === 'workspace-write') {
-    const roots = [...new Set([policy.workspaceRoot, '/tmp', tmpdir()].map(canonicalPath))]
-    forms.push(`(allow file-write* ${roots.map(root => `(subpath ${sbplString(root)})`).join(' ')})`)
-  }
-  return ['-p', forms.join(' ')]
-}
-
 /** Probe whether `bwrap` can create the profile; the provider caches the bounded result. */
 function defaultProbeBwrap(timeoutMs: number): boolean {
   const probe = spawnSync('bwrap', ['--ro-bind', '/', '/', '--dev', '/dev', '--proc', '/proc', '--die-with-parent', '--', 'true'], {
diff --git a/packages/sandbox/sandbox-local/src/profiles.ts b/packages/sandbox/sandbox-local/src/profiles.ts
new file mode 100644
index 0000000000..9303583cbb
--- /dev/null
+++ b/packages/sandbox/sandbox-local/src/profiles.ts
@@ -0,0 +1,67 @@
+/**
+ * Internal platform-profile builders for the local sandbox provider.
+ *
+ * @module @deepseek-ai/dsh-sandbox-local/profiles
+ */
+
+import { realpathSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { grantArgs as landlockGrantArgs } from 'node-addon-landlock-run'
+import type { SandboxPolicy } from '@deepseek-ai/dsh-sandbox'
+
+/**
+ * Build the bwrap profile arguments for one file-effect policy.
+ * @param policy - file-effect policy to express as bwrap mounts.
+ * @returns profile arguments before the trailing separator and command argv.
+ */
+export function bwrapProfileArgs(policy: SandboxPolicy): string[] {
+  const args = ['--ro-bind', '/', '/', '--dev', '/dev', '--proc', '/proc', '--die-with-parent']
+  if (policy.mode === 'workspace-write') {
+    args.push('--tmpfs', '/tmp')
+    args.push('--bind', policy.workspaceRoot, policy.workspaceRoot)
+  }
+  return args
+}
+
+/**
+ * Build the Landlock launcher grants for one file-effect policy.
+ * @param policy - file-effect policy to express as Landlock allow-list grants.
+ * @returns launcher grant arguments before the trailing separator and command argv.
+ */
+export function landlockProfileArgs(policy: SandboxPolicy): string[] {
+  const readWrite = ['/dev/null']
+  if (policy.mode === 'workspace-write') {
+    readWrite.push('/tmp', policy.workspaceRoot)
+  }
+  return landlockGrantArgs({ readOnly: ['/'], readWrite })
+}
+
+/** Resolve a granted root to the canonical path the Seatbelt kernel sees. */
+function canonicalPath(path: string): string {
+  try {
+    return realpathSync(path)
+  } catch {
+    // Missing or unreadable roots stay as spelled; an unresolved root grants
+    // nothing until it exists, which is the conservative outcome.
+    return path
+  }
+}
+
+/** Quote one path as an SBPL string literal. */
+function sbplString(path: string): string {
+  return `"${path.replaceAll('\\', String.raw`\\`).replaceAll('"', String.raw`\"`)}"`
+}
+
+/**
+ * Build the sandbox-exec arguments and SBPL profile for one policy.
+ * @param policy - file-effect policy to express as an SBPL profile.
+ * @returns sandbox-exec arguments before the trailing separator and command argv.
+ */
+export function seatbeltProfileArgs(policy: SandboxPolicy): string[] {
+  const forms = ['(version 1)', '(allow default)', '(deny file-write*)', `(allow file-write* (literal ${sbplString('/dev/null')}))`]
+  if (policy.mode === 'workspace-write') {
+    const roots = [...new Set([policy.workspaceRoot, '/tmp', tmpdir()].map(canonicalPath))]
+    forms.push(`(allow file-write* ${roots.map(root => `(subpath ${sbplString(root)})`).join(' ')})`)
+  }
+  return ['-p', forms.join(' ')]
+}
diff --git a/packages/sandbox/sandbox-local/tests/bwrap.e2e.ts b/packages/sandbox/sandbox-local/tests/bwrap.e2e.ts
index 1e818e1bdf..9a093e4632 100644
--- a/packages/sandbox/sandbox-local/tests/bwrap.e2e.ts
+++ b/packages/sandbox/sandbox-local/tests/bwrap.e2e.ts
@@ -6,7 +6,8 @@ import { join } from 'node:path'
 import { afterEach, describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
 import type { SandboxPolicy } from '@deepseek-ai/dsh-sandbox'
-import { bwrapProfileArgs, LocalSandboxProvider } from '@deepseek-ai/dsh-sandbox-local'
+import { LocalSandboxProvider } from '@deepseek-ai/dsh-sandbox-local'
+import { bwrapProfileArgs } from '../src/profiles.ts'
 
 /**
  * Keyless backend integration through `confine()` and a real bwrap process. With no rung forced,
diff --git a/packages/sandbox/sandbox-local/tests/local.spec.ts b/packages/sandbox/sandbox-local/tests/local.spec.ts
index c221544861..f9efbf992c 100644
--- a/packages/sandbox/sandbox-local/tests/local.spec.ts
+++ b/packages/sandbox/sandbox-local/tests/local.spec.ts
@@ -15,12 +15,10 @@ import { Context } from 'cordis'
 import { SANDBOX_UNAVAILABLE, SandboxUnavailableError } from '@deepseek-ai/dsh-sandbox'
 import type { SandboxPolicy } from '@deepseek-ai/dsh-sandbox'
 import {
-  bwrapProfileArgs,
-  landlockProfileArgs,
   LocalSandboxProvider,
-  seatbeltProfileArgs,
 } from '@deepseek-ai/dsh-sandbox-local'
 import type { Config } from '@deepseek-ai/dsh-sandbox-local'
+import { bwrapProfileArgs, landlockProfileArgs, seatbeltProfileArgs } from '../src/profiles.ts'
 
 const RO: SandboxPolicy = { mode: 'read-only', workspaceRoot: '/ws' }
 const WW: SandboxPolicy = { mode: 'workspace-write', workspaceRoot: '/ws' }
diff --git a/packages/sandbox/sandbox-local/tests/seatbelt.e2e.ts b/packages/sandbox/sandbox-local/tests/seatbelt.e2e.ts
index 2c5a026ddb..6d645b1a3b 100644
--- a/packages/sandbox/sandbox-local/tests/seatbelt.e2e.ts
+++ b/packages/sandbox/sandbox-local/tests/seatbelt.e2e.ts
@@ -6,7 +6,8 @@ import { join } from 'node:path'
 import { afterEach, describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
 import type { SandboxPolicy } from '@deepseek-ai/dsh-sandbox'
-import { LocalSandboxProvider, seatbeltProfileArgs } from '@deepseek-ai/dsh-sandbox-local'
+import { LocalSandboxProvider } from '@deepseek-ai/dsh-sandbox-local'
+import { seatbeltProfileArgs } from '../src/profiles.ts'
 
 /**
  * Keyless backend integration through `confine()` and a real macOS Seatbelt process, with Linux