diff --git a/.github/scripts/run-agent-task/execute-native-agent-task.mjs b/.github/scripts/run-agent-task/execute-native-agent-task.mjs
index 0c58897c0..548f3ffeb 100644
--- a/.github/scripts/run-agent-task/execute-native-agent-task.mjs
+++ b/.github/scripts/run-agent-task/execute-native-agent-task.mjs
@@ -367,9 +367,11 @@ const taskInput = {
         metadata: { workload: request.workload, ...(materializedPackage ? { imported_agent: materializedPackage.identity } : {}), runtime_sources: materializedRuntimeSources?.descriptors ?? [] },
       },
     },
-   },
-   workspaces: request.runner_workspace?.enabled ? [{ target: "/workspace", mode: "readwrite", sourceMode: "repo-backed", seed: { type: "directory", source: workspace, excludePaths: [".git/**", ".codebox/**", "node_modules/**", "vendor/**", "dist/**", "build/**", "coverage/**", ".cache/**"] } }] : [],
- }
+      // agent-task-run unwraps task_input before building the recipe. Keep the
+      // runner seed on that canonical input rather than on the request envelope.
+      workspaces: request.runner_workspace?.enabled ? [{ target: "/workspace", mode: "readwrite", sourceMode: "repo-backed", seed: { type: "directory", source: workspace, excludePaths: [".git/**", ".codebox/**", "node_modules/**", "vendor/**", "dist/**", "build/**", "coverage/**", ".cache/**"] } }] : [],
+    },
+  }
 
 await writeFile(executionInputPath, `${JSON.stringify(taskInput, null, 2)}\n`)
 
@@ -389,12 +391,17 @@ const runtimeResult = sanitizeRuntimeSourceValue(nativeRuntimeResult, privateRun
 assertNoRuntimeSourcePaths(runtimeResult, privateRuntimeSourceRootForSanitization)
 let workspaceApply = { status: "no-op", changedFiles: [] }
 let runnerWorkspaceCore = null
+let downstreamFailure = null
 if (execution.code === 0 && runtimeResult.success === true && request.runner_workspace?.enabled) {
-  runnerWorkspaceCore = await import(pathToFileURL(join(codeboxRoot, "packages/runtime-core/dist/runner-workspace-apply.js")).href)
-  const publicCore = await import(pathToFileURL(join(codeboxRoot, "packages/runtime-core/dist/public.js")).href)
-  const refs = publicCore.normalizePublicArtifactRefDTOs(runtimeResult)
-    .filter((ref) => ref.kind === "codebox-patch" || ref.kind === "codebox-changed-files")
-  workspaceApply = await runnerWorkspaceCore.applyRunnerWorkspacePatch({ artifactRoot: artifactsPath, artifactRefs: refs, workspaceRoot: workspace, writablePaths: String(request.writable_paths || "").split(",").map((value) => value.trim()).filter(Boolean) })
+  try {
+    runnerWorkspaceCore = await import(pathToFileURL(join(codeboxRoot, "packages/runtime-core/dist/runner-workspace-apply.js")).href)
+    const publicCore = await import(pathToFileURL(join(codeboxRoot, "packages/runtime-core/dist/public.js")).href)
+    const refs = publicCore.normalizePublicArtifactRefDTOs(runtimeResult)
+      .filter((ref) => ref.kind === "codebox-patch" || ref.kind === "codebox-changed-files")
+    workspaceApply = await runnerWorkspaceCore.applyRunnerWorkspacePatch({ artifactRoot: artifactsPath, artifactRefs: refs, workspaceRoot: workspace, writablePaths: String(request.writable_paths || "").split(",").map((value) => value.trim()).filter(Boolean) })
+  } catch (error) {
+    downstreamFailure = { stage: "apply", message: bounded(error instanceof Error ? error.message : String(error), MAX_OUTPUT_CHARS) }
+  }
 }
 await cleanupPrivateRuntimeSources()
 assertNoRuntimeSourcePaths(runtimeResult, privateRuntimeSourceRootForSanitization)
@@ -402,7 +409,7 @@ assertNoRuntimeSourcePaths(runtimeResult, privateRuntimeSourceRootForSanitizatio
 await redactArtifactFiles(artifactsPath)
 
 const verification = []
-if (execution.code === 0 && request.run_agent && !request.dry_run) {
+if (execution.code === 0 && request.run_agent && !request.dry_run && !downstreamFailure) {
   const validationDependencies = string(request.validation_dependencies)
   if (validationDependencies) {
     const checkResult = await command("bash", ["-lc", validationDependencies], workspace)
@@ -419,21 +426,30 @@ if (execution.code === 0 && request.run_agent && !request.dry_run) {
 }
 
 const verificationPassed = verification.every((check) => check.success)
+if (!verificationPassed) {
+  downstreamFailure ??= { stage: "verification", message: "Runner workspace verification did not pass." }
+}
 const runtimeRecord = record(runtimeResult)
 const agentResult = record(runtimeRecord.agent_task_run_result)
 let publication = resultValue(runtimeRecord, "metadata.runner_workspace_publication")
 if (execution.code === 0 && runtimeRecord.success === true && verificationPassed && workspaceApply.status === "applied") {
-  await runnerWorkspaceCore.verifyRunnerWorkspaceIntegrity(workspaceApply.integrity)
-  const testPublisher = string(process.env.WP_CODEBOX_TEST_PUBLISHER_MODULE)
-  const publisher = testPublisher ? (await import(pathToFileURL(resolve(testPublisher)).href)).publishRunnerWorkspace : publishRunnerWorkspace
-   const testHook = testPublisher && process.env.WP_CODEBOX_TEST_PUBLISHER_HOOK
-     ? JSON.parse(process.env.WP_CODEBOX_TEST_PUBLISHER_HOOK)
-     : undefined
-   publication = await publisher({ request, changedFiles: workspaceApply.changedFiles, publicationFiles: workspaceApply.publicationFiles, token: process.env.ACCESS_TOKEN || process.env.GITHUB_TOKEN, ...(testHook ? { testHook } : {}) })
-  runtimeRecord.metadata = { ...record(runtimeRecord.metadata), runner_workspace_publication: publication }
-  runtimeRecord.outputs = { ...record(runtimeRecord.outputs), runner_workspace_publication: publication }
-}
-if (request.success?.requires_pr === true && workspaceApply.status === "no-op" && !publication) throw new Error("success_requires_pr cannot succeed for a no-op runner workspace task.")
+  try {
+    await runnerWorkspaceCore.verifyRunnerWorkspaceIntegrity(workspaceApply.integrity)
+    const testPublisher = string(process.env.WP_CODEBOX_TEST_PUBLISHER_MODULE)
+    const publisher = testPublisher ? (await import(pathToFileURL(resolve(testPublisher)).href)).publishRunnerWorkspace : publishRunnerWorkspace
+     const testHook = testPublisher && process.env.WP_CODEBOX_TEST_PUBLISHER_HOOK
+       ? JSON.parse(process.env.WP_CODEBOX_TEST_PUBLISHER_HOOK)
+       : undefined
+     publication = await publisher({ request, changedFiles: workspaceApply.changedFiles, publicationFiles: workspaceApply.publicationFiles, token: process.env.ACCESS_TOKEN || process.env.GITHUB_TOKEN, ...(testHook ? { testHook } : {}) })
+    runtimeRecord.metadata = { ...record(runtimeRecord.metadata), runner_workspace_publication: publication }
+    runtimeRecord.outputs = { ...record(runtimeRecord.outputs), runner_workspace_publication: publication }
+  } catch (error) {
+    downstreamFailure = { stage: "publication", message: bounded(error instanceof Error ? error.message : String(error), MAX_OUTPUT_CHARS) }
+  }
+}
+if (request.success?.requires_pr === true && workspaceApply.status === "no-op" && !publication) {
+  downstreamFailure ??= { stage: "no-op", message: "success_requires_pr cannot succeed for a no-op runner workspace task." }
+}
 let evaluatedProjections = {}
 let projectionError = ""
 try {
@@ -446,8 +462,11 @@ const publicationVerification = publicationRequired && execution.code === 0 && r
   ? await verifyPublishedPullRequest(publication, request.target_repo, workspace)
   : { valid: !publicationRequired, error: "" }
 const publicationPassed = publicationVerification.valid
+if (publicationRequired && !publicationPassed) {
+  downstreamFailure ??= { stage: "publication", message: publicationVerification.error || "Runner workspace publication did not pass verification." }
+}
 const success = request.run_agent && !request.dry_run
-  ? execution.code === 0 && runtimeRecord.success === true && verificationPassed && publicationPassed && !projectionError
+  ? execution.code === 0 && runtimeRecord.success === true && verificationPassed && publicationPassed && !projectionError && !downstreamFailure
   : true
 const status = request.run_agent && !request.dry_run ? (success ? "succeeded" : "failed") : "skipped"
 const result = {
@@ -470,6 +489,7 @@ const result = {
   access: { authorized: true, credential_mode: process.env.GITHUB_TOKEN ? "runner-access-token" : (process.env.OPENAI_API_KEY ? "runner-provider-credentials" : "runner-default-credentials"), policy: { allowed_repos: request.access.allowed_repos } },
   ...(publicationRequired ? { publication_verification: publicationVerification } : {}),
   ...(publicationRequired && !publicationPassed ? { publication_error: "success_requires_pr requires a valid published runner-workspace pull request for target_repo." } : {}),
+  ...(downstreamFailure ? { failure: { code: "wp-codebox.agent-task.downstream", classification: "downstream", ...downstreamFailure } } : {}),
   ...(projectionError ? { projection_error: projectionError } : {}),
 }
 
diff --git a/tests/agent-task-reusable-workflow.test.ts b/tests/agent-task-reusable-workflow.test.ts
index 7ba385b37..020d34057 100644
--- a/tests/agent-task-reusable-workflow.test.ts
+++ b/tests/agent-task-reusable-workflow.test.ts
@@ -225,6 +225,17 @@ assert.deepEqual(nativeTaskInput.task_input.sandbox_tool_policy.tools, hostedDoc
   allowed: true,
   runtime: { environment: "runtime_local", capability_scope: "runtime_local" },
 })), "Hosted Docs Agent run 29298164272 must emit canonical sandbox-local workspace metadata")
+assert.deepEqual(nativeTaskInput.task_input.workspaces, [{
+  target: "/workspace",
+  mode: "readwrite",
+  sourceMode: "repo-backed",
+  seed: {
+    type: "directory",
+    source: tmp,
+    excludePaths: [".git/**", ".codebox/**", "node_modules/**", "vendor/**", "dist/**", "build/**", "coverage/**", ".cache/**"],
+  },
+}], "Hosted failures 29324157852 and 29324563665 placed the runner seed outside task_input, so agent-task-run discarded it")
+assert.equal(nativeTaskInput.workspaces, undefined, "Runner workspace configuration must only use the canonical task_input.workspaces field")
 
 const executeNativeAgentTask = new URL("../.github/scripts/run-agent-task/execute-native-agent-task.mjs", import.meta.url).pathname
 const executeAccessCase = async (candidate: Record<string, unknown>, environment: Record<string, string>) => {
diff --git a/tests/execute-native-agent-task-lifecycle.test.mjs b/tests/execute-native-agent-task-lifecycle.test.mjs
index ceeb5f679..98b2b1ab5 100644
--- a/tests/execute-native-agent-task-lifecycle.test.mjs
+++ b/tests/execute-native-agent-task-lifecycle.test.mjs
@@ -65,6 +65,7 @@ async function run(mode = "success") {
 import { mkdir, readFile, writeFile } from "node:fs/promises"
 import { join } from "node:path"
 const output = process.argv[process.argv.indexOf("--result-file") + 1]
+const input = JSON.parse(await readFile(process.argv[process.argv.indexOf("--input-file") + 1], "utf8"))
 const root = join(process.cwd(), ".codebox", "agent-task-artifacts", "files")
 await mkdir(root, { recursive: true })
 const patch = ${noOp} ? "" : "--- a/README.md\\n+++ b/README.md\\n@@ -1 +1 @@\\n-before\\n+after\\n"
@@ -94,6 +95,7 @@ const result = {
     patch: { artifact: "patch.diff", bytes: ${noOp} ? 0 : 1 },
   },
   metadata: { imported_agent: { slug: "fixture-agent" }, tool_contract: { tools: ["workspace_read", "workspace_edit"] } },
+  agent_runtime_diagnostics: { prepared_paths: { workspaces: input.task_input.workspaces.map((workspace) => ({ target: workspace.target, mode: workspace.mode, metadata: { baselineSource: "fixture-baseline", workspaceRoot: "/workspace", sourceMode: workspace.sourceMode } })) }, sandbox_workspace: { mounts: input.task_input.workspaces.map((workspace) => ({ target: workspace.target })) }, local_executor_root: "/workspace" },
 }
 await writeFile(output, JSON.stringify(result))
 `)
@@ -163,10 +165,16 @@ assert.equal(success.code, 0, success.stderr)
 assert.equal(await readFile(join(success.workspace, "README.md"), "utf8"), "after\n")
 assert.match(success.order, /runtime\nvalidation\nverification\ndrift\npublish\n/)
 assert.equal(success.result.runtime_result.metadata.runner_workspace_publication.pull_request.url, "https://github.com/owner/repo/pull/1")
+assert.equal(success.result.runtime_result.agent_runtime_diagnostics.prepared_paths.workspaces[0].target, "/workspace")
+assert.equal(success.result.runtime_result.agent_runtime_diagnostics.prepared_paths.workspaces[0].mode, "readwrite")
+assert.equal(success.result.runtime_result.agent_runtime_diagnostics.sandbox_workspace.mounts[0].target, "/workspace")
+assert.equal(success.result.runtime_result.agent_runtime_diagnostics.local_executor_root, "/workspace")
 
 const failedVerification = await run("verify-fail")
 assert.equal(failedVerification.code, 1)
 assert(!failedVerification.order.includes("publish"))
+assert.equal(failedVerification.result.failure.stage, "verification")
+assert.equal(failedVerification.result.runtime_result.success, true, "verification failures retain the normalized runtime result")
 
 const denied = await run("deny")
 assert.equal(denied.code, 1)
@@ -175,6 +183,8 @@ assert.equal(denied.order, "runtime\n")
 const noOpRequired = await run("no-op")
 assert.equal(noOpRequired.code, 1)
 assert(!noOpRequired.order.includes("publish"))
+assert.equal(noOpRequired.result.failure.stage, "no-op")
+assert.equal(noOpRequired.result.runtime_result.success, true, "downstream failures retain the normalized runtime result")
 
 const noOpMaintenance = await run("no-op-maintenance")
 assert.equal(noOpMaintenance.code, 0)