perf: add adaptive reasoning effort and token-cost optimizations

src/common/reasoning-effort-manager.ts

@@ -0,0 +1,188 @@
+import type { ReasoningEffort } from "../settings";
+import type { ToolCall, ToolExecutionResult } from "../tools/executor";
+
+// ── Public types ──────────────────────────────────────────────
+
+export type TurnInput = {
+  /** Raw tool calls from the assistant response (before execution). */
+  toolCalls: ToolCall[];
+  /** Execution results after tool calls completed (same order as toolCalls). */
+  toolExecutions: ToolExecutionResult[];
+};
+
+// ── Internal state ───────────────────────────────────────────
+
+type ManagerState = {
+  currentEffort: ReasoningEffort;
+  consecutiveFailures: number;
+  consecutiveIdenticalCalls: number;
+  lastFingerprint: string | null;
+  turnsAtCurrentEffort: number;
+  cleanTurnStreak: number;
+  downgradeCooldownRemaining: number;
+  downgradeThreshold: number;
+  escalateCooldownRemaining: number;
+};
+
+// ── Constants ─────────────────────────────────────────────────
+
+const FAILURE_ESCALATION_THRESHOLD = 2;
+/**
+ * Number of consecutive identical tool calls required to trigger escalation.
+ * Per spec: "≥3 consecutive tool calls with identical (name, arguments) pairs".
+ */
+const REPETITION_ESCALATION_THRESHOLD = 3;
+const DEFAULT_DOWNGRADE_THRESHOLD = 5;
+const DOWNGRADE_COOLDOWN_TURNS = 3;
+const ESCALATE_COOLDOWN_TURNS = 2;
+
+// ── Manager ───────────────────────────────────────────────────
+
+export class RuntimeReasoningEffortManager {
+  private state: ManagerState;
+
+  constructor() {
+    this.state = {
+      currentEffort: "high",
+      consecutiveFailures: 0,
+      consecutiveIdenticalCalls: 0,
+      lastFingerprint: null,
+      turnsAtCurrentEffort: 0,
+      cleanTurnStreak: 0,
+      downgradeCooldownRemaining: 0,
+      downgradeThreshold: DEFAULT_DOWNGRADE_THRESHOLD,
+      escalateCooldownRemaining: 0,
+    };
+  }
+
+  static computeFingerprint(toolCalls: ToolCall[]): string {
+    const normalized = toolCalls.map((tc) => ({
+      name: tc.function.name,
+      args: tc.function.arguments.replace(/\s+/g, ""),
+    }));
+    return JSON.stringify(normalized);
+  }
+
+  evaluate(input: TurnInput): ReasoningEffort | null {
+    const fingerprint = RuntimeReasoningEffortManager.computeFingerprint(input.toolCalls);
+    const allOk = input.toolExecutions.length > 0 && input.toolExecutions.every((e) => e.ok);
+
+    this.state.turnsAtCurrentEffort += 1;
+
+    let result: ReasoningEffort | null;
+    if (this.state.currentEffort === "high") {
+      result = this.evaluateEscalation(input, fingerprint, allOk);
+    } else {
+      result = this.evaluateDowngrade(allOk, fingerprint);
+    }
+
+    // Only decrement cooldowns when no state change occurred.
+    // If escalate()/downgrade() just fired, the new cooldown was set
+    // and should NOT be decremented in the same turn.
+    if (result === null) {
+      this.state.downgradeCooldownRemaining = Math.max(0, this.state.downgradeCooldownRemaining - 1);
+      this.state.escalateCooldownRemaining = Math.max(0, this.state.escalateCooldownRemaining - 1);
+    }
+
+    return result;
+  }
+
+  getCurrentEffort(): ReasoningEffort {
+    return this.state.currentEffort;
+  }
+
+  reset(): void {
+    this.state = {
+      currentEffort: "high",
+      consecutiveFailures: 0,
+      consecutiveIdenticalCalls: 0,
+      lastFingerprint: null,
+      turnsAtCurrentEffort: 0,
+      cleanTurnStreak: 0,
+      downgradeCooldownRemaining: 0,
+      downgradeThreshold: DEFAULT_DOWNGRADE_THRESHOLD,
+      escalateCooldownRemaining: 0,
+    };
+  }
+
+  getState(): Readonly<ManagerState> {
+    return { ...this.state };
+  }
+
+  // ── Private helpers ─────────────────────────────────────────
+
+  private evaluateEscalation(_input: TurnInput, fingerprint: string, allOk: boolean): ReasoningEffort | null {
+    if (this.state.escalateCooldownRemaining > 0) {
+      return null;
+    }
+
+    if (!allOk) {
+      this.state.consecutiveFailures += 1;
+      // A failure breaks the "identical success" streak.
+      this.state.consecutiveIdenticalCalls = 0;
+      if (this.state.consecutiveFailures >= FAILURE_ESCALATION_THRESHOLD) {
+        return this.escalate();
+      }
+    } else {
+      this.state.consecutiveFailures = 0;
+    }
+
+    if (fingerprint === this.state.lastFingerprint && fingerprint !== null && this.state.lastFingerprint !== null) {
+      this.state.consecutiveIdenticalCalls += 1;
+      if (this.state.consecutiveIdenticalCalls >= REPETITION_ESCALATION_THRESHOLD) {
+        return this.escalate();
+      }
+    } else {
+      // First occurrence of this fingerprint — start the streak at 1.
+      // (Per spec: escalation triggers on ≥3 identical calls; the 3rd triggers.)
+      this.state.consecutiveIdenticalCalls = 1;
+    }
+
+    this.state.lastFingerprint = fingerprint;
+    return null;
+  }
+
+  private evaluateDowngrade(allOk: boolean, fingerprint: string): ReasoningEffort | null {
+    if (this.state.downgradeCooldownRemaining > 0) {
+      this.state.lastFingerprint = fingerprint;
+      return null;
+    }
+
+    if (allOk && fingerprint !== this.state.lastFingerprint) {
+      this.state.cleanTurnStreak += 1;
+      if (this.state.cleanTurnStreak >= this.state.downgradeThreshold) {
+        return this.downgrade();
+      }
+    } else if (!allOk) {
+      this.state.cleanTurnStreak = 0;
+    }
+
+    this.state.lastFingerprint = fingerprint;
+    return null;
+  }
+
+  private escalate(): ReasoningEffort {
+    this.state.currentEffort = "max";
+    this.state.consecutiveFailures = 0;
+    this.state.consecutiveIdenticalCalls = 0;
+    this.state.cleanTurnStreak = 0;
+    this.state.downgradeCooldownRemaining = DOWNGRADE_COOLDOWN_TURNS;
+    this.state.turnsAtCurrentEffort = 0;
+    return "max";
+  }
+
+  private downgrade(): ReasoningEffort | null {
+    this.state.currentEffort = "high";
+    this.state.cleanTurnStreak = 0;
+    this.state.escalateCooldownRemaining = ESCALATE_COOLDOWN_TURNS;
+    this.state.consecutiveFailures = 0;
+    this.state.consecutiveIdenticalCalls = 0;
+    this.state.turnsAtCurrentEffort = 0;
+    if (this.state.downgradeThreshold === DEFAULT_DOWNGRADE_THRESHOLD) {
+      this.state.downgradeThreshold = DEFAULT_DOWNGRADE_THRESHOLD * 2;
+    } else {
+      this.state.downgradeThreshold = DEFAULT_DOWNGRADE_THRESHOLD * 4;
+    }
+    return "high";
+  }
+}