feat: harden jsonl runtime reliability

pkg/tools/subagent_runtime_context.go

@@ -0,0 +1,51 @@
+package tools
+
+import "context"
+
+type SubagentExecutionStats struct {
+	Iterations  int
+	Attempts    int
+	Restarts    int
+	FailureCode string
+}
+
+type subagentExecutionStatsKey struct{}
+type subagentIterationBudgetKey struct{}
+
+func WithSubagentExecutionStats(ctx context.Context, stats *SubagentExecutionStats) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	return context.WithValue(ctx, subagentExecutionStatsKey{}, stats)
+}
+
+func RecordSubagentExecutionStats(ctx context.Context, delta SubagentExecutionStats) {
+	if ctx == nil {
+		return
+	}
+	stats, _ := ctx.Value(subagentExecutionStatsKey{}).(*SubagentExecutionStats)
+	if stats == nil {
+		return
+	}
+	stats.Iterations += delta.Iterations
+	stats.Attempts += delta.Attempts
+	stats.Restarts += delta.Restarts
+	if delta.FailureCode != "" {
+		stats.FailureCode = delta.FailureCode
+	}
+}
+
+func WithSubagentIterationBudget(ctx context.Context, budget int) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	return context.WithValue(ctx, subagentIterationBudgetKey{}, budget)
+}
+
+func SubagentIterationBudget(ctx context.Context) (int, bool) {
+	if ctx == nil {
+		return 0, false
+	}
+	budget, ok := ctx.Value(subagentIterationBudgetKey{}).(int)
+	return budget, ok && budget > 0
+}