fix(sandbox): evidence-gate runner failures (round 1)

packages/bash/bash-sandbox/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/bash/bash-sandbox/README.md
-README.md: 035a8ad2401ca608d264049d454359eda7b2b9a7
-README.zh.md: cee27a9baaa539ba07eb1d730ea9bef2004fbeeb
+README.md: 851bedea3589efe164cf49b7e6db1a5f3d64df24
+README.zh.md: f4eb13dd11f8a22dd0a0d594a615567571b1ccde

packages/bash/bash-sandbox/README.md

@@ -17,7 +17,7 @@ Every command is confined by handing the provider the exact `['bash', '-c', comm
 Semantics:
 
 - **Denials are result facts.** A failed run whose stderr carries the selected backend's own denial dialect — the signatures the provider stamps on every wrap (EROFS text under bwrap, EACCES under Landlock, EPERM under Seatbelt) — is reported as `BashRunResult.sandbox.denied: true` (conservative classification, read from the collected stderr tail); every CONFINED run also carries the mode it executed under (`result.sandbox.mode`) and the provider's enforcement completeness (`result.sandbox.enforcement`: `full`, or `partial` on an older Landlock ABI).
-- **Runner failures are sandbox failures, never command failures.** Foreground execution throws `SANDBOX_UNAVAILABLE`; a settled background process stamps `process.sandbox.runnerFailed`, which the bash producer renders through generic `task_output`. Spawn failures also pass through settlement, so confined background handles retain their mode/enforcement facts and release per-process accounting.
+- **Runner failures are sandbox failures, never command failures.** Foreground and background execution use the same structured classifier: a rule's optional exit-code gate and a remaining fatal stderr line must both match after exact informational-line exclusions. A match outranks denial; foreground execution throws `SANDBOX_UNAVAILABLE` with the matched fatal line, while a settled background process stamps `process.sandbox.runnerFailed`, which the bash producer renders through generic `task_output`. Spawn failures also pass through settlement, so confined background handles retain their mode/enforcement facts and release per-process accounting.
 - **Deployment fallback, per-call policy.** [`ctx.sandboxPolicy`](../../sandbox/sandbox-policy/) resolves a complete `SandboxExecutionPolicy` for every tool call: the calling session supplies its mode override and immutable cwd root, while deployment config supplies the fallbacks for agentless calls. An approved escalation changes only that policy's mode; its session root stays attached. `resolve()` carries the policy onto the spec, so overlapping commands from different projects run, classify, and report under their own roots and modes. The capability fact `ctx.bash.sandboxMode` reports the configured default so the tool layer advertises escalation only when this executor is mounted; the static bash tool description separately owns denial and escalation guidance.
 - **File effects only.** Network and process visibility are deliberately not restricted — the mode vocabulary does not pretend to cover what the backend does not enforce.
 - Process mechanics (spawn, process-group kills, output collection/spill, background handles, credential scrub) are inherited from [`dsh-bash-local`](../bash-local/); runner selection lives in [`dsh-sandbox-local`](../../sandbox/sandbox-local/).
@@ -72,7 +72,7 @@ Append-only; newly visible content follows the reusable request prefix and does
 
 #### What the model sees
 
-If no runner can enforce a confined mode, the foreground call propagates the [`SANDBOX_UNAVAILABLE` error owned by `dsh-sandbox`](../../sandbox/sandbox/README.md#confinement-error-indirectly). For an execution-time runner failure, this backend supplies the first stderr line as its detail.
+If no runner can enforce a confined mode, the foreground call propagates the [`SANDBOX_UNAVAILABLE` error owned by `dsh-sandbox`](../../sandbox/sandbox/README.md#confinement-error-indirectly). For an execution-time runner failure, this backend supplies the matched fatal stderr line as its detail and preserves the original stderr collection.
 
 #### Token effect
 

packages/bash/bash-sandbox/README.zh.md

@@ -17,7 +17,7 @@
 语义：
 
 - **拒绝是结果事实。** 如果一次失败运行的 stderr 包含所选后端自身的拒绝方言，即提供方在每次包装时加上的特征（bwrap 下的 EROFS 文本、Landlock 下的 EACCES、Seatbelt 下的 EPERM），则结果报告 `BashRunResult.sandbox.denied: true`（从已收集的 stderr 尾部进行保守分类）。每次受限制运行还会携带执行时模式（`result.sandbox.mode`）与提供方强制执行完整性（`result.sandbox.enforcement`：`full`，或在较旧 Landlock ABI 上为 `partial`）。
-- **Runner 失败是沙箱失败，绝不是命令失败。** 前台执行会抛出 `SANDBOX_UNAVAILABLE`；已结算的后台进程会标记 `process.sandbox.runnerFailed`，Bash 结果生成方通过通用 `task_output` 渲染它。spawn 失败也会经过结算，因此受限制的后台句柄会保留自身的模式／强制执行事实，并释放每进程计数。
+- **Runner 失败是沙箱失败，绝不是命令失败。** 前台与后台执行使用同一个结构化分类器：先按整行精确匹配排除信息性行，随后规则的可选退出码门控和余下 stderr 中的一行致命诊断必须同时匹配。匹配结果优先于拒绝；前台执行会抛出 `SANDBOX_UNAVAILABLE` 并附带匹配到的致命行，已结算的后台进程则会标记 `process.sandbox.runnerFailed`，Bash 结果生成方通过通用 `task_output` 渲染它。spawn 失败也会经过结算，因此受限制的后台句柄会保留自身的模式／强制执行事实，并释放每进程计数。
 - **部署回退，每次调用策略。** [`ctx.sandboxPolicy`](../../sandbox/sandbox-policy/) 为每次工具调用解析完整的 `SandboxExecutionPolicy`：调用会话提供自身的模式覆盖与不可变 cwd 根目录，部署配置则为无 agent（智能体）调用提供回退。已批准的升权只更改该策略的模式，会话根目录仍然附着其上。`resolve()` 把策略带入 spec，因此来自不同项目的重叠命令会在各自的根目录与模式下运行、分类和报告。能力事实 `ctx.bash.sandboxMode` 报告已配置的默认值，因此工具层只在装载该执行器时才公布升权；静态 bash 工具描述则单独负责拒绝与升级引导。
 - **只限制文件影响。** 设计上不限制网络与进程可见性：模式词汇不会声称覆盖后端未强制执行的范围。
 - 进程机制（spawn、进程组终止、输出收集／spill、后台句柄、凭证清理）继承自 [`dsh-bash-local`](../bash-local/)；runner 选择位于 [`dsh-sandbox-local`](../../sandbox/sandbox-local/)。
@@ -72,7 +72,7 @@
 
 #### 模型看到的内容
 
-如果没有 runner 能强制执行受限模式，前台调用会传播 [`SANDBOX_UNAVAILABLE` 错误](../../sandbox/sandbox/README.md#confinement-error-indirectly)；该错误由 `dsh-sandbox` 定义。如果 runner 在执行时失败，此后端会提供第一行 stderr 作为详细信息。
+如果没有 runner 能强制执行受限模式，前台调用会传播 [`SANDBOX_UNAVAILABLE` 错误](../../sandbox/sandbox/README.md#confinement-error-indirectly)；该错误由 `dsh-sandbox` 定义。如果 runner 在执行时失败，此后端会提供匹配到的致命 stderr 行作为详细信息，并保留原始 stderr 收集结果。
 
 #### Token 影响
 

packages/bash/bash-sandbox/src/helpers.ts

@@ -5,6 +5,13 @@
  */
 
 import type { BashRunResult } from '@deepseek-ai/dsh-bash'
+import type { RunnerFailureRule } from '@deepseek-ai/dsh-sandbox'
+
+/** Fatal runner evidence retained for infrastructure-error detail. */
+interface RunnerFailureMatch {
+  /** The original stderr line that matched a fatal signature. */
+  detail: string
+}
 
 /**
  * Quote one string as a single-quoted POSIX shell word.
@@ -26,13 +33,33 @@ export function classifyDenial(result: BashRunResult, signatures: readonly strin
 }
 
 /**
- * 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.
+ * Classify one settled process against the selected backend's structured
+ * runner-failure rules. Each rule requires a nonzero exit, its optional
+ * exit-code gate, and a fatal signature on one stderr line after exact
+ * informational lines are excluded.
+ * @param exitCode - process exit code; null means signal termination.
+ * @param stderr - collected stderr text, left unchanged.
+ * @param rules - structured runner-failure rules from the active wrap.
+ * @returns the first matching fatal line, or undefined when evidence is insufficient.
  */
-export function classifyRunnerFailure(result: BashRunResult, signatures: readonly string[]): boolean {
-  return matchesSignature(result.exitCode, result.stderr.text, signatures)
+export function classifyRunnerFailure(
+  exitCode: number | null,
+  stderr: string,
+  rules: readonly RunnerFailureRule[],
+): RunnerFailureMatch | undefined {
+  if (exitCode === null || exitCode === 0) return undefined
+  const lines = stderr.split(/\r?\n/)
+  for (const rule of rules) {
+    if (rule.allowedExitCodes !== undefined && !rule.allowedExitCodes.includes(exitCode)) continue
+    const informationalLines = new Set((rule.informationalLines ?? []).map(line => line.toLowerCase()))
+    const fatalSignatures = rule.fatalSignatures.map(signature => signature.toLowerCase())
+    for (const line of lines) {
+      const lowered = line.toLowerCase()
+      if (informationalLines.has(lowered)) continue
+      if (fatalSignatures.some(signature => lowered.includes(signature))) return { detail: line }
+    }
+  }
+  return undefined
 }
 
 /**

packages/bash/bash-sandbox/src/index.ts

@@ -11,7 +11,14 @@
 import { Context } from 'cordis'
 import type { BashExecRequest, BashExecSpec, BashProcess, BashRunResult } from '@deepseek-ai/dsh-bash'
 import { SandboxUnavailableError } from '@deepseek-ai/dsh-sandbox'
-import type { ConfinedSandboxMode, SandboxEnforcement, SandboxExecutionPolicy, SandboxMode, SandboxPolicy } from '@deepseek-ai/dsh-sandbox'
+import type {
+  ConfinedSandboxMode,
+  RunnerFailureRule,
+  SandboxEnforcement,
+  SandboxExecutionPolicy,
+  SandboxMode,
+  SandboxPolicy,
+} from '@deepseek-ai/dsh-sandbox'
 import type {} from '@deepseek-ai/dsh-sandbox-policy'
 import { LocalBashExecutor } from '@deepseek-ai/dsh-bash-local'
 import type { Config as LocalConfig } from '@deepseek-ai/dsh-bash-local'
@@ -51,7 +58,7 @@ export class SandboxBashExecutor extends LocalBashExecutor {
     mode: ConfinedSandboxMode
     enforcement: SandboxEnforcement
     denialSignatures: readonly string[]
-    runnerFailureSignatures: readonly string[]
+    runnerFailureRules: readonly RunnerFailureRule[]
   }>()
 
   constructor(ctx: Context, config: Config) {
@@ -84,10 +91,11 @@ export class SandboxBashExecutor extends LocalBashExecutor {
     }
     const confined = this.confine(spec.command, { ...policy, mode })
     const result = await super.run({ ...spec, command: confined.command })
-    // Runner failure outranks denial because the command did not run. Throw the
-    // same fail-closed error as confine-time discovery with the first stderr line.
-    if (classifyRunnerFailure(result, confined.runnerFailureSignatures)) {
-      throw new SandboxUnavailableError(mode, result.stderr.text.trim().split('\n')[0])
+    // Runner failure outranks denial because the command did not run. Carry
+    // the matched fatal line, not an informational line that preceded it.
+    const runnerFailure = classifyRunnerFailure(result.exitCode, result.stderr.text, confined.runnerFailureRules)
+    if (runnerFailure !== undefined) {
+      throw new SandboxUnavailableError(mode, runnerFailure.detail)
     }
     return { ...result, sandbox: { mode, denied: classifyDenial(result, confined.denialSignatures), enforcement: confined.enforcement } }
   }
@@ -99,8 +107,8 @@ export class SandboxBashExecutor extends LocalBashExecutor {
     // Install facts synchronously; promise settlement cannot run before start() returns.
     const confined = this.confine(spec.command, { ...policy, mode })
     const proc = super.start({ ...spec, command: confined.command })
-    const { enforcement, denialSignatures, runnerFailureSignatures } = confined
-    this.processFacts.set(proc, { mode, enforcement, denialSignatures, runnerFailureSignatures })
+    const { enforcement, denialSignatures, runnerFailureRules } = confined
+    this.processFacts.set(proc, { mode, enforcement, denialSignatures, runnerFailureRules })
     return proc
   }
 
@@ -113,7 +121,7 @@ export class SandboxBashExecutor extends LocalBashExecutor {
     if (facts !== undefined) {
       this.processFacts.delete(proc)
       // Runner failure outranks denial because its diagnostics may contain denial terms.
-      const runnerFailed = matchesSignature(proc.exitCode, stderr, facts.runnerFailureSignatures)
+      const runnerFailed = classifyRunnerFailure(proc.exitCode, stderr, facts.runnerFailureRules) !== undefined
       proc.sandbox = {
         mode: facts.mode,
         denied: !runnerFailed && matchesSignature(proc.exitCode, stderr, facts.denialSignatures),
@@ -136,14 +144,14 @@ export class SandboxBashExecutor extends LocalBashExecutor {
     command: string
     enforcement: SandboxEnforcement
     denialSignatures: readonly string[]
-    runnerFailureSignatures: readonly string[]
+    runnerFailureRules: readonly RunnerFailureRule[]
   } {
     const confined = this.ctx.sandbox.confine(['bash', '-c', command], policy)
     return {
       command: `exec ${confined.argv.map(shellQuote).join(' ')}`,
       enforcement: confined.enforcement,
       denialSignatures: confined.denialSignatures,
-      runnerFailureSignatures: confined.runnerFailureSignatures,
+      runnerFailureRules: confined.runnerFailureRules,
     }
   }
 }

packages/bash/bash-sandbox/tests/partial-landlock.spec.ts

@@ -0,0 +1,125 @@
+/**
+ * Deterministic composition proof for the partial-Landlock diagnostic: the
+ * real local provider and sandbox bash executor wrap commands through a POSIX
+ * fake launcher that prints the native informational line before exec.
+ */
+
+import { mkdtemp, rm, writeFile } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { afterEach, describe, expect, it } from 'vitest'
+import { Context } from 'cordis'
+import { SANDBOX_UNAVAILABLE } from '@deepseek-ai/dsh-sandbox'
+import { LocalSandboxProvider } from '@deepseek-ai/dsh-sandbox-local'
+import { SandboxPolicyService } from '@deepseek-ai/dsh-sandbox-policy'
+import { SandboxBashExecutor } from '@deepseek-ai/dsh-bash-sandbox'
+import LocalSubprocessService from '@deepseek-ai/dsh-subprocess-local'
+
+const NOTICE = 'landlock-run: partial enforcement (older Landlock ABI)'
+const FATAL = 'landlock-run: landlock ruleset error: Invalid argument'
+
+const contexts: Context[] = []
+const tempDirs: string[] = []
+
+afterEach(async () => {
+  await Promise.all(contexts.splice(0).map(ctx => ctx.fiber.dispose()))
+  await Promise.all(tempDirs.splice(0).map(dir => rm(dir, { recursive: true, force: true })))
+})
+
+/** Write a fake native launcher that reports partial enforcement, then execs or fails. */
+async function fakeLauncher(fatal: boolean): Promise<string> {
+  const dir = await mkdtemp(join(tmpdir(), 'dsh-partial-landlock-'))
+  tempDirs.push(dir)
+  const launcher = join(dir, 'landlock-run')
+  const fatalBranch = fatal ? `printf '%s\\n' '${FATAL}' >&2\nexit 125\n` : ''
+  await writeFile(launcher, `#!/bin/sh
+while [ "$#" -gt 0 ]; do
+  case "$1" in
+    --ro|--rw) shift 2 ;;
+    --) shift; break ;;
+    *) printf '%s\\n' 'landlock-run: usage error: unexpected fake argument' >&2; exit 125 ;;
+  esac
+done
+printf '%s\\n' '${NOTICE}' >&2
+${fatalBranch}exec "$@"
+`, { mode: 0o755 })
+  return launcher
+}
+
+async function setup(fatal = false): Promise<SandboxBashExecutor> {
+  const ctx = new Context()
+  contexts.push(ctx)
+  await ctx.plugin(LocalSandboxProvider, {})
+  const sandbox = ctx.sandbox as LocalSandboxProvider
+  sandbox.internals = {
+    platform: 'linux',
+    probeBwrap: () => false,
+    probeLandlock: () => 'partial',
+    landlockLauncher: await fakeLauncher(fatal),
+  }
+  await ctx.plugin(SandboxPolicyService, { mode: 'read-only', workspaceRoot: process.cwd() })
+  await ctx.plugin(LocalSubprocessService)
+  await ctx.plugin(SandboxBashExecutor, { cwd: process.cwd(), timeoutMs: 5_000 })
+  return ctx.bash as SandboxBashExecutor
+}
+
+describe('partial Landlock runner-failure classification', () => {
+  it('keeps true, false, and child exit 125 as child outcomes when the notice is the only runner line', async () => {
+    const bash = await setup()
+    for (const [command, exitCode] of [['true', 0], ['false', 1], ['exit 125', 125]] as const) {
+      const result = await bash.run(bash.resolve({ command }))
+      expect(result.exitCode).toBe(exitCode)
+      expect(result.stderr.text).toBe(`${NOTICE}\n`)
+      expect(result.sandbox).toEqual({ mode: 'read-only', denied: false, enforcement: 'partial' })
+    }
+  })
+
+  it('reports the fatal line after the notice as SANDBOX_UNAVAILABLE detail', async () => {
+    const bash = await setup(true)
+    const error = await bash.run(bash.resolve({ command: 'true' })).catch((value: unknown) => value)
+    expect(error).toMatchObject({ name: 'SandboxUnavailableError', code: SANDBOX_UNAVAILABLE })
+    expect(error).toBeInstanceOf(Error)
+    expect((error as Error).message).toContain(`Runner failure: ${FATAL}`)
+    expect((error as Error).message).not.toContain(NOTICE)
+  })
+
+  it('classifies a notice plus child Permission denied as a denial, not runner failure', async () => {
+    const bash = await setup()
+    const result = await bash.run(bash.resolve({ command: 'printf "%s\\n" "child: Permission denied" >&2; exit 1' }))
+    expect(result.stderr.text).toBe(`${NOTICE}\nchild: Permission denied\n`)
+    expect(result.sandbox).toEqual({ mode: 'read-only', denied: true, enforcement: 'partial' })
+  })
+
+  it('applies the same evidence rule to notice-only background exits', async () => {
+    const bash = await setup()
+    for (const command of ['false', 'exit 125']) {
+      const task = bash.start(bash.resolve({ command }))
+      await task.done
+      expect(task.sandbox).toEqual({ mode: 'read-only', denied: false, enforcement: 'partial' })
+      expect(task.readOutput().delta).toContain(NOTICE)
+    }
+  })
+
+  it('classifies a background notice plus child Permission denied as denial', async () => {
+    const bash = await setup()
+    const task = bash.start(bash.resolve({ command: 'printf "%s\\n" "child: Permission denied" >&2; exit 1' }))
+    await task.done
+    expect(task.sandbox).toEqual({ mode: 'read-only', denied: true, enforcement: 'partial' })
+    expect(task.readOutput().delta).toContain(NOTICE)
+  })
+
+  it('makes a background fatal line outrank denial text after the notice', async () => {
+    const bash = await setup(true)
+    const task = bash.start(bash.resolve({ command: 'true' }))
+    await task.done
+    expect(task.sandbox).toEqual({
+      mode: 'read-only',
+      denied: false,
+      enforcement: 'partial',
+      runnerFailed: true,
+    })
+    const output = task.readOutput().delta
+    expect(output).toContain(NOTICE)
+    expect(output).toContain(FATAL)
+  })
+})

packages/bash/bash-sandbox/tests/sandbox.spec.ts

@@ -30,12 +30,12 @@ interface ConfineCall {
 /** The Linux file-denial dialects the fake wraps carry — matches the unix-permission denials the tests below produce. */
 const UNIX_SIGNATURES = ['read-only file system', 'permission denied'] as const
 
-/** The runner-failure prefix the fake wraps carry (a fake-runner: error line marks the sandbox itself failing). */
-const RUNNER_FAILURE = ['fake-runner: '] as const
+/** The runner-failure rule the fake wraps carry (a fake-runner: error line marks the sandbox itself failing). */
+const RUNNER_FAILURE = [{ fatalSignatures: ['fake-runner: '] }] as const
 
 /** A passthrough wrap: the caller's argv unchanged, asserted full — commands run unconfined, deterministically. */
 const passthrough = (argv: readonly string[]): ConfinedArgv =>
-  ({ argv: [...argv], enforcement: 'full', denialSignatures: UNIX_SIGNATURES, runnerFailureSignatures: RUNNER_FAILURE })
+  ({ argv: [...argv], enforcement: 'full', denialSignatures: UNIX_SIGNATURES, runnerFailureRules: RUNNER_FAILURE })
 
 /**
  * Boot a context with a recording fake `ctx.sandbox` (behavior injectable
@@ -93,7 +93,7 @@ describe('the provider hand-off', () => {
   it('a wrapped argv from the provider is what actually spawns (prefix survives, quoting round-trips)', async () => {
     // The fake wraps with `env MARKER=...` — a real (if tiny) runner prefix:
     // the sentinel only prints if the executor spawned the WRAPPED argv.
-    const { bash } = await setup({}, argv => ({ argv: ['env', 'DSH_WRAP=1', ...argv], enforcement: 'full', denialSignatures: UNIX_SIGNATURES, runnerFailureSignatures: RUNNER_FAILURE }))
+    const { bash } = await setup({}, argv => ({ argv: ['env', 'DSH_WRAP=1', ...argv], enforcement: 'full', denialSignatures: UNIX_SIGNATURES, runnerFailureRules: RUNNER_FAILURE }))
     const result = await bash.run(bash.resolve({ command: 'printf "%s" "$DSH_WRAP"' }))
     expect(result.stdout.text).toBe('1')
     expect(result.sandbox).toEqual({ mode: 'read-only', denied: false, enforcement: 'full' })
@@ -234,10 +234,47 @@ describe('classifyDenial', () => {
 })
 
 describe('classifyRunnerFailure', () => {
-  it('matches the dialect case-insensitively on BOTH sides — the seam declares it so, and producers compose signatures from runtime data (an argv0 path, the shell\'s `No such file or directory`)', () => {
-    const signatures = ['exec: /Opt/Runners/bwrap: not found', '/Opt/Runners/bwrap: No such file or directory']
-    expect(classifyRunnerFailure(runResult(127, 'bash: /Opt/Runners/bwrap: No such file or directory'), signatures)).toBe(true)
-    expect(classifyRunnerFailure(runResult(127, 'BASH: LINE 1: EXEC: /OPT/RUNNERS/BWRAP: NOT FOUND'), signatures)).toBe(true)
+  it('matches an outer-shell rule case-insensitively only at its exit codes and configured argv0', () => {
+    const rules = [{
+      allowedExitCodes: [126, 127],
+      fatalSignatures: ['exec: /Opt/Runners/bwrap: not found', '/Opt/Runners/bwrap: No such file or directory'],
+    }]
+    expect(classifyRunnerFailure(127, 'bash: /Opt/Runners/bwrap: No such file or directory', rules)?.detail)
+      .toBe('bash: /Opt/Runners/bwrap: No such file or directory')
+    expect(classifyRunnerFailure(126, 'BASH: LINE 1: EXEC: /OPT/RUNNERS/BWRAP: NOT FOUND', rules)?.detail)
+      .toBe('BASH: LINE 1: EXEC: /OPT/RUNNERS/BWRAP: NOT FOUND')
+    expect(classifyRunnerFailure(125, 'bash: /Opt/Runners/bwrap: No such file or directory', rules)).toBeUndefined()
+    expect(classifyRunnerFailure(127, 'bash: /other/bwrap: No such file or directory', rules)).toBeUndefined()
+  })
+
+  it('requires Landlock exit 125 plus a non-notice fatal line and returns that original line', () => {
+    const notice = 'landlock-run: partial enforcement (older Landlock ABI)'
+    const rules = [{ allowedExitCodes: [125], fatalSignatures: ['landlock-run: '], informationalLines: [notice] }]
+    expect(classifyRunnerFailure(1, notice, rules)).toBeUndefined()
+    expect(classifyRunnerFailure(2, notice, rules)).toBeUndefined()
+    expect(classifyRunnerFailure(125, notice, rules)).toBeUndefined()
+    expect(classifyRunnerFailure(125, notice.toUpperCase(), rules)).toBeUndefined()
+    expect(classifyRunnerFailure(125, `${notice}: extra detail`, rules))
+      .toEqual({ detail: `${notice}: extra detail` })
+    expect(classifyRunnerFailure(125, `${notice}\nlandlock-run: exec failed: No such file or directory`, rules))
+      .toEqual({ detail: 'landlock-run: exec failed: No such file or directory' })
+  })
+
+  it.each([
+    'landlock-run: usage error: missing `-- <argv>...` command',
+    'landlock-run: landlock is not enforced by this kernel (ABI unsupported or disabled)',
+    'landlock-run: cannot open rule path: /gone: No such file or directory',
+    'landlock-run: landlock ruleset error: Invalid argument',
+    'landlock-run: exec failed: Permission denied',
+    'landlock-run: out of memory',
+    'landlock-run: future fatal diagnostic',
+  ])('keeps known and future Landlock fatal diagnostics fail-closed: %s', (fatal) => {
+    const rules = [{
+      allowedExitCodes: [125],
+      fatalSignatures: ['landlock-run: '],
+      informationalLines: ['landlock-run: partial enforcement (older Landlock ABI)'],
+    }]
+    expect(classifyRunnerFailure(125, fatal, rules)).toEqual({ detail: fatal })
   })
 })
 
@@ -253,7 +290,7 @@ describe('result facts', () => {
   })
 
   it('carries the provider\'s partial-enforcement fact through unchanged', async () => {
-    const { bash } = await setup({}, argv => ({ argv: [...argv], enforcement: 'partial', denialSignatures: UNIX_SIGNATURES, runnerFailureSignatures: RUNNER_FAILURE }))
+    const { bash } = await setup({}, argv => ({ argv: [...argv], enforcement: 'partial', denialSignatures: UNIX_SIGNATURES, runnerFailureRules: RUNNER_FAILURE }))
     const result = await bash.run(bash.resolve({ command: 'true' }))
     expect(result.sandbox).toEqual({ mode: 'read-only', denied: false, enforcement: 'partial' })
   })
@@ -284,7 +321,7 @@ describe('background sandbox facts', () => {
   it('a foreground runner failure throws the fail-closed error, never a task result', async () => {
     // The wrap's runner prefix on a failed run means the SANDBOX broke and
     // the command never ran — the late twin of the confine-time throw, with
-    // the runner's own first stderr line carried as the cause.
+    // the matched fatal stderr line carried as the cause.
     const { bash } = await setup()
     const run = bash.run(bash.resolve({ command: 'echo "fake-runner: ruleset rejected" >&2; exit 125' }))
     await expect(run).rejects.toThrow(expect.objectContaining({ code: SANDBOX_UNAVAILABLE }))
@@ -315,7 +352,7 @@ describe('background sandbox facts', () => {
     let call = 0
     const { bash } = await setup({}, (argv) => {
       const wrap = wraps[Math.min(call++, wraps.length - 1)] as Pick<ConfinedArgv, 'enforcement' | 'denialSignatures'>
-      return { argv: [...argv], ...wrap, runnerFailureSignatures: RUNNER_FAILURE }
+      return { argv: [...argv], ...wrap, runnerFailureRules: RUNNER_FAILURE }
     })
     const slow = bash.start(bash.resolve({ command: 'sleep 0.4; echo "x: Permission denied" >&2; exit 1' }))
     const quick = bash.start(bash.resolve({ command: 'true' }))