diff --git a/src/agents/pi-embedded-runner/run.ts b/src/agents/pi-embedded-runner/run.ts
index da37d9ee69a..109dffe9eca 100644
--- a/src/agents/pi-embedded-runner/run.ts
+++ b/src/agents/pi-embedded-runner/run.ts
@@ -5,8 +5,7 @@ import {
   ensureContextEnginesInitialized,
   resolveContextEngine,
 } from "../../context-engine/index.js";
-import { type BackoffPolicy, computeBackoff, sleepWithAbort } from "../../infra/backoff.js";
-import { generateSecureToken } from "../../infra/secure-random.js";
+import { computeBackoff, sleepWithAbort } from "../../infra/backoff.js";
 import { getGlobalHookRunner } from "../../plugins/hook-runner-global.js";
 import { prepareProviderRuntimeAuth } from "../../plugins/provider-runtime.js";
 import type { PluginHookBeforeAgentStartResult } from "../../plugins/types.js";
@@ -76,6 +75,19 @@ import { log } from "./logger.js";
 import { resolveModelAsync } from "./model.js";
 import { runEmbeddedAttempt } from "./run/attempt.js";
 import { createFailoverDecisionLogger } from "./run/failover-observation.js";
+import {
+  buildErrorAgentMeta,
+  buildUsageAgentMetaFields,
+  createCompactionDiagId,
+  OVERLOAD_FAILOVER_BACKOFF_POLICY,
+  resolveActiveErrorContext,
+  resolveMaxRunRetryIterations,
+  RUNTIME_AUTH_REFRESH_MARGIN_MS,
+  RUNTIME_AUTH_REFRESH_MIN_DELAY_MS,
+  RUNTIME_AUTH_REFRESH_RETRY_MS,
+  type RuntimeAuthState,
+  scrubAnthropicRefusalMagic,
+} from "./run/helpers.js";
 import type { RunEmbeddedPiAgentParams } from "./run/params.js";
 import { buildEmbeddedRunPayloads } from "./run/payloads.js";
 import {
@@ -83,134 +95,11 @@ import {
   truncateOversizedToolResultsInSession,
 } from "./tool-result-truncation.js";
 import type { EmbeddedPiAgentMeta, EmbeddedPiRunResult } from "./types.js";
-import {
-  createUsageAccumulator,
-  mergeUsageIntoAccumulator,
-  resolveLastCallUsage,
-  toNormalizedUsage,
-  type UsageAccumulator,
-} from "./usage-accumulator.js";
+import { createUsageAccumulator, mergeUsageIntoAccumulator } from "./usage-accumulator.js";
 import { describeUnknownError } from "./utils.js";
 
 type ApiKeyInfo = ResolvedProviderAuth;
 
-type RuntimeAuthState = {
-  sourceApiKey: string;
-  authMode: string;
-  profileId?: string;
-  expiresAt?: number;
-  refreshTimer?: ReturnType<typeof setTimeout>;
-  refreshInFlight?: Promise<void>;
-};
-
-const RUNTIME_AUTH_REFRESH_MARGIN_MS = 5 * 60 * 1000;
-const RUNTIME_AUTH_REFRESH_RETRY_MS = 60 * 1000;
-const RUNTIME_AUTH_REFRESH_MIN_DELAY_MS = 5 * 1000;
-// Keep overload pacing noticeable enough to avoid tight retry bursts, but short
-// enough that fallback still feels responsive within a single turn.
-const OVERLOAD_FAILOVER_BACKOFF_POLICY: BackoffPolicy = {
-  initialMs: 250,
-  maxMs: 1_500,
-  factor: 2,
-  jitter: 0.2,
-};
-
-// Avoid Anthropic's refusal test token poisoning session transcripts.
-const ANTHROPIC_MAGIC_STRING_TRIGGER_REFUSAL = "ANTHROPIC_MAGIC_STRING_TRIGGER_REFUSAL";
-const ANTHROPIC_MAGIC_STRING_REPLACEMENT = "ANTHROPIC MAGIC STRING TRIGGER REFUSAL (redacted)";
-
-function scrubAnthropicRefusalMagic(prompt: string): string {
-  if (!prompt.includes(ANTHROPIC_MAGIC_STRING_TRIGGER_REFUSAL)) {
-    return prompt;
-  }
-  return prompt.replaceAll(
-    ANTHROPIC_MAGIC_STRING_TRIGGER_REFUSAL,
-    ANTHROPIC_MAGIC_STRING_REPLACEMENT,
-  );
-}
-function createCompactionDiagId(): string {
-  return `ovf-${Date.now().toString(36)}-${generateSecureToken(4)}`;
-}
-
-// Defensive guard for the outer run loop across all retry branches.
-const BASE_RUN_RETRY_ITERATIONS = 24;
-const RUN_RETRY_ITERATIONS_PER_PROFILE = 8;
-const MIN_RUN_RETRY_ITERATIONS = 32;
-const MAX_RUN_RETRY_ITERATIONS = 160;
-
-function resolveMaxRunRetryIterations(profileCandidateCount: number): number {
-  const scaled =
-    BASE_RUN_RETRY_ITERATIONS +
-    Math.max(1, profileCandidateCount) * RUN_RETRY_ITERATIONS_PER_PROFILE;
-  return Math.min(MAX_RUN_RETRY_ITERATIONS, Math.max(MIN_RUN_RETRY_ITERATIONS, scaled));
-}
-
-function resolveActiveErrorContext(params: {
-  lastAssistant: { provider?: string; model?: string } | undefined;
-  provider: string;
-  model: string;
-}): { provider: string; model: string } {
-  return {
-    provider: params.lastAssistant?.provider ?? params.provider,
-    model: params.lastAssistant?.model ?? params.model,
-  };
-}
-
-function buildUsageAgentMetaFields(params: {
-  usageAccumulator: UsageAccumulator;
-  lastAssistantUsage?: UsageLike | null;
-  lastRunPromptUsage: ReturnType<typeof normalizeUsage> | undefined;
-  /** API-reported total from the most recent call, mirroring the success path correction. */
-  lastTurnTotal?: number;
-}): Pick<EmbeddedPiAgentMeta, "usage" | "lastCallUsage" | "promptTokens"> {
-  const usage = toNormalizedUsage(params.usageAccumulator);
-  // Keep `usage.total` aligned with the API-reported latest-call total when
-  // available; accumulated totals are for billing, not context display.
-  if (usage && params.lastTurnTotal && params.lastTurnTotal > 0) {
-    usage.total = params.lastTurnTotal;
-  }
-  const lastCallUsage = resolveLastCallUsage(params.lastAssistantUsage, params.usageAccumulator);
-  const promptTokens = derivePromptTokens(params.lastRunPromptUsage);
-  return {
-    usage,
-    lastCallUsage,
-    promptTokens,
-  };
-}
-
-/**
- * Build agentMeta for error return paths, preserving accumulated usage so that
- * session totalTokens reflects the actual context size rather than going stale.
- * Without this, error returns omit usage and the session keeps whatever
- * totalTokens was set by the previous successful run.
- */
-function buildErrorAgentMeta(params: {
-  sessionId: string;
-  provider: string;
-  model: string;
-  usageAccumulator: UsageAccumulator;
-  lastRunPromptUsage: ReturnType<typeof normalizeUsage> | undefined;
-  lastAssistant?: { usage?: unknown } | null;
-  /** API-reported total from the most recent call, mirroring the success path correction. */
-  lastTurnTotal?: number;
-}): EmbeddedPiAgentMeta {
-  const usageMeta = buildUsageAgentMetaFields({
-    usageAccumulator: params.usageAccumulator,
-    lastAssistantUsage: params.lastAssistant?.usage as UsageLike | undefined,
-    lastRunPromptUsage: params.lastRunPromptUsage,
-    lastTurnTotal: params.lastTurnTotal,
-  });
-  return {
-    sessionId: params.sessionId,
-    provider: params.provider,
-    model: params.model,
-    // Only include usage fields when we have actual data from prior API calls.
-    ...(usageMeta.usage ? { usage: usageMeta.usage } : {}),
-    ...(usageMeta.lastCallUsage ? { lastCallUsage: usageMeta.lastCallUsage } : {}),
-    ...(usageMeta.promptTokens ? { promptTokens: usageMeta.promptTokens } : {}),
-  };
-}
-
 export async function runEmbeddedPiAgent(
   params: RunEmbeddedPiAgentParams,
 ): Promise<EmbeddedPiRunResult> {
diff --git a/src/agents/pi-embedded-runner/run/helpers.ts b/src/agents/pi-embedded-runner/run/helpers.ts
new file mode 100644
index 00000000000..049a02247d8
--- /dev/null
+++ b/src/agents/pi-embedded-runner/run/helpers.ts
@@ -0,0 +1,128 @@
+import { type BackoffPolicy } from "../../../infra/backoff.js";
+import { generateSecureToken } from "../../../infra/secure-random.js";
+import { derivePromptTokens, normalizeUsage } from "../../usage.js";
+import type { EmbeddedPiAgentMeta } from "../types.js";
+import { toLastCallUsage, toNormalizedUsage, type UsageAccumulator } from "../usage-accumulator.js";
+
+type UsageSnapshot = {
+  input?: number;
+  output?: number;
+  cacheRead?: number;
+  cacheWrite?: number;
+  total?: number;
+};
+
+export type RuntimeAuthState = {
+  sourceApiKey: string;
+  authMode: string;
+  profileId?: string;
+  expiresAt?: number;
+  refreshTimer?: ReturnType<typeof setTimeout>;
+  refreshInFlight?: Promise<void>;
+};
+
+export const RUNTIME_AUTH_REFRESH_MARGIN_MS = 5 * 60 * 1000;
+export const RUNTIME_AUTH_REFRESH_RETRY_MS = 60 * 1000;
+export const RUNTIME_AUTH_REFRESH_MIN_DELAY_MS = 5 * 1000;
+
+// Keep overload pacing noticeable enough to avoid tight retry bursts, but short
+// enough that fallback still feels responsive within a single turn.
+export const OVERLOAD_FAILOVER_BACKOFF_POLICY: BackoffPolicy = {
+  initialMs: 250,
+  maxMs: 1_500,
+  factor: 2,
+  jitter: 0.2,
+};
+
+const ANTHROPIC_MAGIC_STRING_TRIGGER_REFUSAL = "ANTHROPIC_MAGIC_STRING_TRIGGER_REFUSAL";
+const ANTHROPIC_MAGIC_STRING_REPLACEMENT = "ANTHROPIC MAGIC STRING TRIGGER REFUSAL (redacted)";
+
+// Avoid Anthropic's refusal test token poisoning session transcripts.
+export function scrubAnthropicRefusalMagic(prompt: string): string {
+  if (!prompt.includes(ANTHROPIC_MAGIC_STRING_TRIGGER_REFUSAL)) {
+    return prompt;
+  }
+  return prompt.replaceAll(
+    ANTHROPIC_MAGIC_STRING_TRIGGER_REFUSAL,
+    ANTHROPIC_MAGIC_STRING_REPLACEMENT,
+  );
+}
+
+export function createCompactionDiagId(): string {
+  return `ovf-${Date.now().toString(36)}-${generateSecureToken(4)}`;
+}
+
+const BASE_RUN_RETRY_ITERATIONS = 24;
+const RUN_RETRY_ITERATIONS_PER_PROFILE = 8;
+const MIN_RUN_RETRY_ITERATIONS = 32;
+const MAX_RUN_RETRY_ITERATIONS = 160;
+
+// Defensive guard for the outer run loop across all retry branches.
+export function resolveMaxRunRetryIterations(profileCandidateCount: number): number {
+  const scaled =
+    BASE_RUN_RETRY_ITERATIONS +
+    Math.max(1, profileCandidateCount) * RUN_RETRY_ITERATIONS_PER_PROFILE;
+  return Math.min(MAX_RUN_RETRY_ITERATIONS, Math.max(MIN_RUN_RETRY_ITERATIONS, scaled));
+}
+
+export function resolveActiveErrorContext(params: {
+  lastAssistant: { provider?: string; model?: string } | undefined;
+  provider: string;
+  model: string;
+}): { provider: string; model: string } {
+  return {
+    provider: params.lastAssistant?.provider ?? params.provider,
+    model: params.lastAssistant?.model ?? params.model,
+  };
+}
+
+export function buildUsageAgentMetaFields(params: {
+  usageAccumulator: UsageAccumulator;
+  lastAssistantUsage?: UsageSnapshot | null;
+  lastRunPromptUsage: UsageSnapshot | undefined;
+  lastTurnTotal?: number;
+}): Pick<EmbeddedPiAgentMeta, "usage" | "lastCallUsage" | "promptTokens"> {
+  const usage = toNormalizedUsage(params.usageAccumulator);
+  if (usage && params.lastTurnTotal && params.lastTurnTotal > 0) {
+    usage.total = params.lastTurnTotal;
+  }
+  const lastCallUsage =
+    normalizeUsage(params.lastAssistantUsage as never) ?? toLastCallUsage(params.usageAccumulator);
+  const promptTokens = derivePromptTokens(params.lastRunPromptUsage);
+  return {
+    usage,
+    lastCallUsage,
+    promptTokens,
+  };
+}
+
+/**
+ * Build agentMeta for error return paths, preserving accumulated usage so that
+ * session totalTokens reflects the actual context size rather than going stale.
+ * Without this, error returns omit usage and the session keeps whatever
+ * totalTokens was set by the previous successful run.
+ */
+export function buildErrorAgentMeta(params: {
+  sessionId: string;
+  provider: string;
+  model: string;
+  usageAccumulator: UsageAccumulator;
+  lastRunPromptUsage: UsageSnapshot | undefined;
+  lastAssistant?: { usage?: unknown } | null;
+  lastTurnTotal?: number;
+}): EmbeddedPiAgentMeta {
+  const usageMeta = buildUsageAgentMetaFields({
+    usageAccumulator: params.usageAccumulator,
+    lastAssistantUsage: params.lastAssistant?.usage as UsageSnapshot | undefined,
+    lastRunPromptUsage: params.lastRunPromptUsage,
+    lastTurnTotal: params.lastTurnTotal,
+  });
+  return {
+    sessionId: params.sessionId,
+    provider: params.provider,
+    model: params.model,
+    ...(usageMeta.usage ? { usage: usageMeta.usage } : {}),
+    ...(usageMeta.lastCallUsage ? { lastCallUsage: usageMeta.lastCallUsage } : {}),
+    ...(usageMeta.promptTokens ? { promptTokens: usageMeta.promptTokens } : {}),
+  };
+}