Extract paired turn fallback planning

src/paired-turn-fallback.ts

@@ -0,0 +1,116 @@
+import type { AgentTriggerReason } from './agent-error-detection.js';
+import type { AgentType, PairedRoomRole } from './types.js';
+
+const CODEX_HANDOFF_REASONS = new Set<AgentTriggerReason>([
+  '429',
+  'usage-exhausted',
+  'auth-expired',
+  'org-access-denied',
+  'session-failure',
+]);
+
+export interface CodexFallbackHandoffRecord {
+  source_role: PairedRoomRole;
+  target_role: PairedRoomRole;
+  source_agent_type: AgentType;
+  target_agent_type: 'codex';
+  prompt: string;
+  start_seq: number | null;
+  end_seq: number | null;
+  reason: string;
+  intended_role: PairedRoomRole;
+}
+
+export interface CodexFallbackHandoffPlan {
+  handoff: CodexFallbackHandoffRecord;
+  activateOwnerFailoverReason?: string;
+  logMessage: string;
+}
+
+export type CodexFallbackResolution =
+  | { type: 'none' }
+  | { type: 'skip'; logMessage: string }
+  | { type: 'handoff'; plan: CodexFallbackHandoffPlan };
+
+export function resolveCodexFallbackHandoff(args: {
+  activeRole: PairedRoomRole;
+  effectiveAgentType: AgentType;
+  hasReviewer: boolean;
+  fallbackEnabled: boolean;
+  reason: AgentTriggerReason;
+  sawVisibleOutput: boolean;
+  prompt: string;
+  startSeq?: number | null;
+  endSeq?: number | null;
+}): CodexFallbackResolution {
+  if (args.sawVisibleOutput || !CODEX_HANDOFF_REASONS.has(args.reason)) {
+    return { type: 'none' };
+  }
+
+  if (!args.hasReviewer) {
+    return { type: 'none' };
+  }
+
+  if (!args.fallbackEnabled) {
+    return {
+      type: 'skip',
+      logMessage: 'Fallback disabled for role, skipping handoff',
+    };
+  }
+
+  const baseHandoff = {
+    source_role: args.activeRole,
+    source_agent_type: args.effectiveAgentType,
+    target_agent_type: 'codex' as const,
+    prompt: args.prompt,
+    start_seq: args.startSeq ?? null,
+    end_seq: args.endSeq ?? null,
+  };
+
+  if (args.activeRole === 'arbiter') {
+    return {
+      type: 'handoff',
+      plan: {
+        handoff: {
+          ...baseHandoff,
+          target_role: 'arbiter',
+          intended_role: 'arbiter',
+          reason: `arbiter-claude-${args.reason}`,
+        },
+        logMessage:
+          'Claude arbiter unavailable, handed off arbiter turn to codex',
+      },
+    };
+  }
+
+  if (args.activeRole === 'reviewer') {
+    return {
+      type: 'handoff',
+      plan: {
+        handoff: {
+          ...baseHandoff,
+          target_role: 'reviewer',
+          intended_role: 'reviewer',
+          reason: `reviewer-claude-${args.reason}`,
+        },
+        logMessage:
+          'Claude reviewer unavailable, handed off review turn to codex-review',
+      },
+    };
+  }
+
+  return {
+    type: 'handoff',
+    plan: {
+      handoff: {
+        ...baseHandoff,
+        target_role: args.activeRole,
+        intended_role: args.activeRole,
+        reason: `claude-${args.reason}`,
+      },
+      activateOwnerFailoverReason: `claude-${args.reason}`,
+      logMessage:
+        'Claude unavailable, handed off current owner turn to codex fallback',
+    },
+  };
+}