diff --git a/packages/components/src/components/DynamicSquiggleViewer.tsx b/packages/components/src/components/DynamicSquiggleViewer.tsx
index 61fc3c5585..d470f34faa 100644
--- a/packages/components/src/components/DynamicSquiggleViewer.tsx
+++ b/packages/components/src/components/DynamicSquiggleViewer.tsx
@@ -2,7 +2,11 @@ import { forwardRef } from "react";
 
 import { SquiggleViewer } from "../index.js";
 import { SquiggleOutput } from "../lib/hooks/useSquiggle.js";
-import { getResultVariables, getResultValue } from "../lib/utility.js";
+import {
+  getResultVariables,
+  getResultValue,
+  getResultError,
+} from "../lib/utility.js";
 import { CodeEditorHandle } from "./CodeEditor/index.js";
 import { PartialPlaygroundSettings } from "./PlaygroundSettings.js";
 import { SquiggleViewerHandle } from "./SquiggleViewer/index.js";
@@ -42,6 +46,7 @@ export const DynamicSquiggleViewer = forwardRef<SquiggleViewerHandle, Props>(
             ref={viewerRef}
             resultVariables={getResultVariables(squiggleOutput)}
             resultItem={getResultValue(squiggleOutput)}
+            resultError={getResultError(squiggleOutput)}
             editor={editor}
             rootPathOverride={rootPathOverride}
           />
diff --git a/packages/components/src/components/SquiggleViewer/index.tsx b/packages/components/src/components/SquiggleViewer/index.tsx
index 02d0c4efcf..ca37dcface 100644
--- a/packages/components/src/components/SquiggleViewer/index.tsx
+++ b/packages/components/src/components/SquiggleViewer/index.tsx
@@ -31,6 +31,7 @@ export type SquiggleViewerProps = {
   /** The output of squiggle's run */
   resultVariables: result<SqDictValue, SqError>;
   resultItem: result<SqValue, SqError> | undefined;
+  resultError: SqError | undefined;
   editor?: CodeEditorHandle;
   rootPathOverride?: SqValuePath;
 } & PartialPlaygroundSettings;
@@ -39,9 +40,10 @@ const SquiggleViewerOuter = forwardRef<
   SquiggleViewerHandle,
   SquiggleViewerProps
 >(function SquiggleViewerOuter(
-  { resultVariables, resultItem, rootPathOverride },
+  { resultVariables, resultItem, resultError, rootPathOverride },
   ref
 ) {
+  console.log("ERROR", resultError);
   const { focused, dispatch, getCalculator } = useViewerContext();
   const unfocus = useUnfocus();
   const focus = useFocus();
@@ -137,6 +139,7 @@ const SquiggleViewerOuter = forwardRef<
   return (
     <div>
       {focusedNavigation}
+      {resultError && <SquiggleErrorAlert error={resultError} />}
       {body()}
     </div>
   );
@@ -147,6 +150,7 @@ const innerComponent = forwardRef<SquiggleViewerHandle, SquiggleViewerProps>(
     {
       resultVariables,
       resultItem,
+      resultError,
       editor,
       rootPathOverride,
       ...partialPlaygroundSettings
@@ -171,6 +175,7 @@ const innerComponent = forwardRef<SquiggleViewerHandle, SquiggleViewerProps>(
         <SquiggleViewerOuter
           resultVariables={resultVariables}
           resultItem={resultItem}
+          resultError={resultError}
           rootPathOverride={rootPathOverride}
           ref={ref}
         />
diff --git a/packages/components/src/lib/hooks/useSquiggle.ts b/packages/components/src/lib/hooks/useSquiggle.ts
index 503a48bb02..97be1e34bf 100644
--- a/packages/components/src/lib/hooks/useSquiggle.ts
+++ b/packages/components/src/lib/hooks/useSquiggle.ts
@@ -7,6 +7,7 @@ import {
   SqDict,
   SqValue,
   result,
+  SqRuntimeError,
 } from "@quri/squiggle-lang";
 import { WINDOW_VARIABLE_NAME } from "../constants.js";
 
@@ -38,6 +39,7 @@ export type SquiggleOutput = {
       exports: SqDict;
       result: SqValue;
       bindings: SqDict;
+      error: SqRuntimeError | undefined;
     },
     SqError
   >;
@@ -101,6 +103,7 @@ export function useSquiggle(args: SquiggleArgs): UseSquiggleOutput {
         project.setContinues(sourceId, continues);
         await project.run(sourceId);
         const output = project.getOutput(sourceId);
+        console.log("output", output);
         const executionTime = Date.now() - startTime;
 
         setSquiggleOutput({
diff --git a/packages/components/src/lib/utility.ts b/packages/components/src/lib/utility.ts
index ef6046ca88..74d2efeb01 100644
--- a/packages/components/src/lib/utility.ts
+++ b/packages/components/src/lib/utility.ts
@@ -4,6 +4,7 @@ import {
   SqDictValue,
   result,
   resultMap,
+  SqRuntimeError,
 } from "@quri/squiggle-lang";
 
 import { SquiggleOutput } from "./hooks/useSquiggle.js";
@@ -59,6 +60,16 @@ export function getResultValue({
   }
 }
 
+export function getResultError({
+  output,
+}: SquiggleOutput): SqRuntimeError | undefined {
+  if (output.ok) {
+    return output.value.error;
+  } else {
+    return undefined;
+  }
+}
+
 export function getErrors(result: SquiggleOutput["output"]) {
   if (!result.ok) {
     return [result.value];
diff --git a/packages/squiggle-lang/src/public/SqProject/ProjectItem.ts b/packages/squiggle-lang/src/public/SqProject/ProjectItem.ts
index 3472339814..430bcc19c3 100644
--- a/packages/squiggle-lang/src/public/SqProject/ProjectItem.ts
+++ b/packages/squiggle-lang/src/public/SqProject/ProjectItem.ts
@@ -17,6 +17,7 @@ export type RunOutput = {
   result: Value;
   bindings: Bindings;
   exports: Bindings;
+  error: SqError | undefined;
 };
 
 export type Import =
@@ -220,10 +221,13 @@ export class ProjectItem {
         throw new Error("Expected Program expression");
       }
 
-      const [result, contextAfterEvaluation] = evaluate(expression.value, {
-        ...context,
-        evaluate: asyncEvaluate,
-      });
+      const [result, contextAfterEvaluation, error] = evaluate(
+        expression.value,
+        {
+          ...context,
+          evaluate: asyncEvaluate,
+        }
+      );
 
       const bindings = contextAfterEvaluation.stack.asBindings();
       const exportNames = new Set(expression.value.value.exports);
@@ -232,6 +236,7 @@ export class ProjectItem {
         result,
         bindings,
         exports,
+        error,
       });
     } catch (e: unknown) {
       this.failRun(new SqRuntimeError(IRuntimeError.fromException(e)));
diff --git a/packages/squiggle-lang/src/public/SqProject/index.ts b/packages/squiggle-lang/src/public/SqProject/index.ts
index f3b6b64761..dae83b51b5 100644
--- a/packages/squiggle-lang/src/public/SqProject/index.ts
+++ b/packages/squiggle-lang/src/public/SqProject/index.ts
@@ -7,7 +7,7 @@ import { ImmutableMap } from "../../utility/immutableMap.js";
 import * as Result from "../../utility/result.js";
 import { Value, vDict } from "../../value/index.js";
 
-import { SqError, SqOtherError } from "../SqError.js";
+import { SqError, SqOtherError, SqRuntimeError } from "../SqError.js";
 import { SqDict } from "../SqValue/SqDict.js";
 import { SqValue, wrapValue } from "../SqValue/index.js";
 import { SqValueContext } from "../SqValueContext.js";
@@ -16,6 +16,7 @@ import { SqValuePath } from "../SqValuePath.js";
 import { SqLinker } from "../SqLinker.js";
 import { SqOutputResult } from "../types.js";
 import { Import, ProjectItem, RunOutput } from "./ProjectItem.js";
+import { IRuntimeError } from "../../errors/IError.js";
 
 function getNeedToRunError() {
   return new SqOtherError("Need to run");
@@ -267,7 +268,15 @@ export class SqProject {
         )
     );
 
-    return Result.Ok({ result, bindings, exports });
+    const error = internalOutputR.value.error;
+    return Result.Ok({
+      result,
+      bindings,
+      exports,
+      error: error
+        ? new SqRuntimeError(IRuntimeError.fromException(error))
+        : undefined,
+    });
   }
 
   getResult(sourceId: string): Result.result<SqValue, SqError> {
diff --git a/packages/squiggle-lang/src/public/types.ts b/packages/squiggle-lang/src/public/types.ts
index 0a933d2d5f..5516ab354e 100644
--- a/packages/squiggle-lang/src/public/types.ts
+++ b/packages/squiggle-lang/src/public/types.ts
@@ -1,5 +1,5 @@
 import { result } from "../utility/result.js";
-import { SqError } from "./SqError.js";
+import { SqError, SqRuntimeError } from "./SqError.js";
 import { SqValue } from "./SqValue/index.js";
 import { SqDict } from "./SqValue/SqDict.js";
 
@@ -7,6 +7,7 @@ export type SqOutput = {
   result: SqValue;
   bindings: SqDict;
   exports: SqDict;
+  error: SqRuntimeError | undefined;
 };
 
 export type SqOutputResult = result<SqOutput, SqError>;
diff --git a/packages/squiggle-lang/src/reducer/index.ts b/packages/squiggle-lang/src/reducer/index.ts
index 24d5f2a8d3..fd8413fb6f 100644
--- a/packages/squiggle-lang/src/reducer/index.ts
+++ b/packages/squiggle-lang/src/reducer/index.ts
@@ -13,6 +13,7 @@ import {
 } from "../errors/messages.js";
 import { compileAst } from "../expression/compile.js";
 import { Expression } from "../expression/index.js";
+import { SqError, SqRuntimeError } from "../index.js";
 import { getStdLib } from "../library/index.js";
 import { ImmutableMap } from "../utility/immutableMap.js";
 import * as Result from "../utility/result.js";
@@ -33,13 +34,13 @@ import { UserDefinedLambdaParameter, UserDefinedLambda } from "./lambda.js";
 export type ReducerFn = (
   expression: Expression,
   context: Context.ReducerContext
-) => [Value, Context.ReducerContext];
+) => [Value, Context.ReducerContext, SqError | undefined];
 
 type SubReducerFn<T extends Expression["type"] = Expression["type"]> = (
   expressionValue: Extract<Expression, { type: T }>["value"],
   context: Context.ReducerContext,
   ast: ASTNode
-) => [Value, Context.ReducerContext];
+) => [Value, Context.ReducerContext, SqError | undefined];
 
 function throwFrom(
   error: ErrorMessage,
@@ -104,7 +105,7 @@ const evaluateBlock: SubReducerFn<"Block"> = (statements, context) => {
       currentContext
     );
   }
-  return [currentValue, context]; // throw away block's context
+  return [currentValue, context, undefined]; // throw away block's context
 };
 
 const evaluateProgram: SubReducerFn<"Program"> = (expressionValue, context) => {
@@ -113,12 +114,20 @@ const evaluateProgram: SubReducerFn<"Program"> = (expressionValue, context) => {
   let currentValue: Value = vVoid();
 
   for (const statement of expressionValue.statements) {
-    [currentValue, currentContext] = context.evaluate(
-      statement,
-      currentContext
-    );
+    try {
+      [currentValue, currentContext] = context.evaluate(
+        statement,
+        currentContext
+      );
+    } catch (e: unknown) {
+      return [
+        currentValue,
+        currentContext,
+        new SqRuntimeError(IRuntimeError.fromException(e)),
+      ];
+    }
   }
-  return [currentValue, currentContext];
+  return [currentValue, currentContext, undefined];
 };
 
 const evaluateArray: SubReducerFn<"Array"> = (expressionValue, context) => {
@@ -127,7 +136,7 @@ const evaluateArray: SubReducerFn<"Array"> = (expressionValue, context) => {
     return value;
   });
   const value = vArray(values);
-  return [value, context];
+  return [value, context, undefined];
 };
 
 const evaluateDict: SubReducerFn<"Dict"> = (expressionValue, context, ast) => {
@@ -148,7 +157,7 @@ const evaluateDict: SubReducerFn<"Dict"> = (expressionValue, context, ast) => {
       })
     )
   );
-  return [value, context];
+  return [value, context, undefined];
 };
 
 const evaluateAssign: SubReducerFn<"Assign"> = (expressionValue, context) => {
@@ -163,6 +172,7 @@ const evaluateAssign: SubReducerFn<"Assign"> = (expressionValue, context) => {
       evaluate: context.evaluate,
       inFunction: context.inFunction,
     },
+    undefined,
   ];
 };
 
@@ -171,11 +181,11 @@ const evaluateResolvedSymbol: SubReducerFn<"ResolvedSymbol"> = (
   context
 ) => {
   const value = context.stack.get(expressionValue.offset);
-  return [value, context];
+  return [value, context, undefined];
 };
 
 const evaluateValue: SubReducerFn<"Value"> = (expressionValue, context) => {
-  return [expressionValue, context];
+  return [expressionValue, context, undefined];
 };
 
 const evaluateTernary: SubReducerFn<"Ternary"> = (
@@ -199,7 +209,7 @@ const evaluateTernary: SubReducerFn<"Ternary"> = (
     predicateResult.value ? expressionValue.ifTrue : expressionValue.ifFalse,
     context
   );
-  return [value, context];
+  return [value, context, undefined];
 };
 
 const evaluateLambda: SubReducerFn<"Lambda"> = (
@@ -246,7 +256,7 @@ const evaluateLambda: SubReducerFn<"Lambda"> = (
       ast.location
     )
   );
-  return [value, context];
+  return [value, context, undefined];
 };
 
 const evaluateCall: SubReducerFn<"Call"> = (expressionValue, context, ast) => {
@@ -262,7 +272,7 @@ const evaluateCall: SubReducerFn<"Call"> = (expressionValue, context, ast) => {
         context,
         ast // we pass the ast of a current expression here, to put it on frameStack and in the resulting value
       );
-      return [result, context];
+      return [result, context, undefined];
     }
     default:
       return throwFrom(new RENotAFunction(lambda.toString()), context, ast);