diff --git a/extension/src/buildcore.ts b/extension/src/buildcore.ts
index a751255f..dcb803d7 100644
--- a/extension/src/buildcore.ts
+++ b/extension/src/buildcore.ts
@@ -4,7 +4,8 @@
 
 import * as fs from 'fs';
 import * as path from 'path';
-import type { CodeListingMap, FileData, Segment, WorkerError, WorkerErrorResult, WorkerResult } from "../../src/common/workertypes";
+import type { BuildProducts, FileData, WorkerError, WorkerErrorResult, WorkerResult } from "../../src/common/workertypes";
+import { buildProducts } from "../../src/common/workertypes";
 import { toInternalError } from "../../src/common/telemetry";
 import { getBasePlatform, isProbablyBinary } from "../../src/common/util";
 import { getToolForPlatform } from "../../src/common/toolselect";
@@ -33,16 +34,11 @@ export interface BuildDiagnostic {
   msg: string;
 }
 
-export interface BuildOutcome {
+export interface BuildOutcome extends BuildProducts {
   success: boolean;
   tool: string;
   output?: Uint8Array;
   diagnostics: BuildDiagnostic[];
-  listings?: CodeListingMap;
-  symbolmap?: { [sym: string]: number };
-  /** symbol -> size in bytes, for the toolchains that report it */
-  symbolsizes?: { [sym: string]: number };
-  segments?: Segment[];
   /** every project path the build read */
   paths: string[];
   /**
@@ -142,7 +138,7 @@ export class Builder {
       var r = result as any;
       var outcome: BuildOutcome = {
         success: true, tool, paths, files, diagnostics: [],
-        output: r.output, listings: r.listings, symbolmap: r.symbolmap, symbolsizes: r.symbolsizes, segments: r.segments,
+        output: r.output, ...buildProducts(r),
       };
       this.last.set(key, outcome);
       return outcome;
diff --git a/extension/src/extension.ts b/extension/src/extension.ts
index 5727b3d0..67c4463d 100644
--- a/extension/src/extension.ts
+++ b/extension/src/extension.ts
@@ -19,6 +19,7 @@ import { BuildReason, BuildScheduler } from './autobuild';
 import { PRESET_SCHEME, PresetFileSystem, Templates } from './templates';
 import { chooseForFile, detectDirectoryAt, detectionSummary, describeDetection, describeFinding, dontAskKey, FolderFinding, platformName, scanFolder } from './detection';
 import { Detection, classifyFinding, isBuildableSource } from '../../src/common/detect';
+import { buildProducts } from '../../src/common/workertypes';
 import { TOOL_META } from '../../src/common/toolmeta';
 import { ASSET_URLS, AssetStore } from './assets';
 import { projectReadme, writeLauncher } from './terminalcli';
@@ -398,7 +399,7 @@ async function runScriptHeadless(target: Target, build: BuildOutcome, script: st
     var run = async () => {
       await worker.call('start', target.platform, build.output, build.files, { paused: true });
       var mainPath = path.posix.basename(target.main.path);
-      return worker.call<ScriptResult>('script', script, { listings: build.listings, symbols: build.symbolmap, mainPath, paths: build.paths });
+      return worker.call<ScriptResult>('script', script, { ...buildProducts(build), mainPath, paths: build.paths });
     };
     return await Promise.race([run(), stop]);
   } finally {
@@ -1426,6 +1427,6 @@ async function launchForDebug(folder: vscode.WorkspaceFolder | undefined, args:
   if (!result.output) throw new Error('the build produced no ROM to run');
   if (!await startEmulator(target, result, { paused: true })) throw new Error('the emulator failed to start; see Output');
   var mainPath = path.posix.basename(target.main.path);
-  await emu!.call('debug', 'setBuild', { listings: result.listings, symbols: result.symbolmap, symbolsizes: result.symbolsizes, mainPath, paths: result.paths });
+  await emu!.call('debug', 'setBuild', { ...buildProducts(result), mainPath, paths: result.paths });
   return { root: path.dirname(target.main.fsPath) };
 }
diff --git a/extension/test/emuworker.test.ts b/extension/test/emuworker.test.ts
index cc8bbeef..f32f4f5a 100644
--- a/extension/test/emuworker.test.ts
+++ b/extension/test/emuworker.test.ts
@@ -160,7 +160,7 @@ describe('extension emuworker', function () {
       files: new ProjectFileProvider(read, ROOT, 'nes'),
     });
     await rpc.call('start', 'nes', nes.output, nes.files, { paused: true });
-    var build = { listings: nes.listings, symbols: nes.symbolmap, mainPath: 'attributes.c', paths: nes.paths };
+    var build = { listings: nes.listings, symbolmap: nes.symbolmap, mainPath: 'attributes.c', paths: nes.paths };
     var r = await rpc.call<ScriptResult>('script', 'run 30; mem main 4', build);
     assert.equal(r.error, undefined);
     assert.equal(r.frame, 30);
@@ -251,7 +251,7 @@ describe('extension emuworker', function () {
     it('starts stopped, then stops at a source breakpoint, steps, and steps back', async function () {
       var s = await rpc.call<EmuStatus>('start', 'mw8080bw', built.output, built.files, { paused: true });
       assert.equal(s.state, 'paused');
-      await debug('setBuild', { listings: built.listings, symbols: built.symbolmap, mainPath: 'game2.c', paths: built.paths });
+      await debug('setBuild', { listings: built.listings, symbolmap: built.symbolmap, mainPath: 'game2.c', paths: built.paths });
       var [bp] = await debug('setBreakpoints', [{ id: 1, type: 'source', file: 'game2.c', line: 166, enabled: true }]);
       assert.ok(bp.verified, bp.message);
       await debug('continue');
@@ -280,7 +280,7 @@ describe('extension emuworker', function () {
       });
       assert.deepEqual(nes.diagnostics, []);
       await rpc.call('start', 'nes', nes.output, nes.files, { paused: true });
-      await debug('setBuild', { listings: nes.listings, symbols: nes.symbolmap, mainPath: 'hello.c', paths: nes.paths });
+      await debug('setBuild', { listings: nes.listings, symbolmap: nes.symbolmap, mainPath: 'hello.c', paths: nes.paths });
       var [bp] = await debug('setBreakpoints', [{ id: 1, type: 'source', file: 'hello.c', line: 19, enabled: true }]);
       assert.ok(bp.verified, bp.message);
       await debug('continue');
@@ -306,7 +306,7 @@ describe('extension emuworker', function () {
         files: new ProjectFileProvider(read, ROOT, 'nes'),
       });
       await rpc.call('start', 'nes', nes.output, nes.files, { paused: true });
-      await debug('setBuild', { listings: nes.listings, symbols: nes.symbolmap, mainPath: 'scroll.c', paths: nes.paths });
+      await debug('setBuild', { listings: nes.listings, symbolmap: nes.symbolmap, mainPath: 'scroll.c', paths: nes.paths });
       var caps = await debug('capabilities');
       assert.equal(caps.tree, true);
       assert.equal(caps.write, true);
@@ -333,7 +333,7 @@ describe('extension emuworker', function () {
     it('drives the debug adapter through the worker, as the extension does', async function () {
       var backend = new WorkerDebugBackend((method, ...args) => rpc.call('debug', method, ...args), async () => {
         await rpc.call('start', 'mw8080bw', built.output, built.files, { paused: true });
-        await rpc.call('debug', 'setBuild', { listings: built.listings, symbols: built.symbolmap, mainPath: 'game2.c', paths: built.paths });
+        await rpc.call('debug', 'setBuild', { listings: built.listings, symbolmap: built.symbolmap, mainPath: 'game2.c', paths: built.paths });
         return { root: '/proj' };
       }, async () => { });
       rpc.on('stopped', e => backend.handleStop(e));
diff --git a/src/common/debugcontroller.ts b/src/common/debugcontroller.ts
index fca22567..67b85025 100644
--- a/src/common/debugcontroller.ts
+++ b/src/common/debugcontroller.ts
@@ -13,7 +13,7 @@ import { DEFAULT_MAX_FRAMES, EmuCore } from "./emucore";
 import { getListingForFile, processListings, stripLocalPath } from "./projectcore";
 import { Timestamp, timestamp, timestampsEqual } from "./timeline";
 import { getFilenameForPath, getFilenamePrefix } from "./util";
-import { CodeListingMap, SourceFile, SourceLine, SourceLocation } from "./workertypes";
+import { BuildProducts, CodeListingMap, SourceFile, SourceLine, SourceLocation } from "./workertypes";
 
 export type StopReason = 'breakpoint' | 'step' | 'pause' | 'goto' | 'entry' | 'halt' | 'exception';
 
@@ -371,17 +371,18 @@ function sameLine(a: SourceLocation, b: SourceLocation): boolean {
   return a.line === b.line && a.path === b.path;
 }
 
+/** A build's products, and the project files they came from. */
+export interface BuildInfo extends BuildProducts {
+  mainPath: string;
+  /** the project files, which name the source a listing came from */
+  paths?: string[];
+}
+
 /**
  * A DebugContext from a build: source lines from its listings, and symbols.
  * `paths` are the project files, which name the source a listing came from.
  */
-export function buildDebugContext(build: {
-  listings?: CodeListingMap,
-  symbols?: { [name: string]: number },
-  symbolsizes?: { [name: string]: number },
-  mainPath: string,
-  paths?: string[],
-}): DebugContext {
+export function buildDebugContext(build: BuildInfo): DebugContext {
   const listings = build.listings || {};
   // listings that came over an RPC have lost their SourceFile methods
   if (Object.values(listings).some(l => l.lines && !(l.sourcefile instanceof SourceFile))) processListings(listings);
@@ -390,9 +391,9 @@ export function buildDebugContext(build: {
     const want = getFilenamePrefix(getFilenameForPath(stripLocalPath(name, build.mainPath)));
     return paths.find(p => getFilenamePrefix(getFilenameForPath(p)) === want) || name;
   };
-  const symbolAddrs = [...new Set(Object.values(build.symbols || {}))].sort((a, b) => a - b);
+  const symbolAddrs = [...new Set(Object.values(build.symbolmap || {}))].sort((a, b) => a - b);
   return {
-    symbols: build.symbols,
+    symbols: build.symbolmap,
     symbolsizes: build.symbolsizes,
     getListingForFile: path => getListingForFile(listings, path, build.mainPath),
     sourceAt(pc: number) {
diff --git a/src/common/workertypes.ts b/src/common/workertypes.ts
index cbbccf7d..94a30171 100644
--- a/src/common/workertypes.ts
+++ b/src/common/workertypes.ts
@@ -203,6 +203,18 @@ export interface WorkerOutputResult<T> {
   origin?: number
 }
 
+/**
+ * What a build produces for the debugger and the memory map, besides the ROM.
+ * Types that carry a build's products extend this, and `buildProducts` copies
+ * them, so a new field is added here and in that function only.
+ */
+export type BuildProducts = Pick<WorkerOutputResult<unknown>, 'listings' | 'symbolmap' | 'symbolsizes' | 'segments'>;
+
+export function buildProducts(r: BuildProducts): BuildProducts {
+  const { listings, symbolmap, symbolsizes, segments } = r;
+  return { listings, symbolmap, symbolsizes, segments };
+}
+
 export function isUnchanged(result: WorkerResult) : result is WorkerUnchangedResult {
   return ('unchanged' in result);
 }
diff --git a/src/tools/8bws.ts b/src/tools/8bws.ts
index ff863c15..236d608c 100644
--- a/src/tools/8bws.ts
+++ b/src/tools/8bws.ts
@@ -19,6 +19,7 @@ import { EmuTarget, loadPlatform } from './emutarget';
 import { RUN_SCRIPT_HELP, RunScript, parseNum } from './runscript';
 import { verifyReplay } from './verifyreplay';
 import { buildDebugContext } from '../common/debugcontroller';
+import { buildProducts } from '../common/workertypes';
 import type { BuildInfo } from './debugservice';
 import { parseSymbolFile } from '../common/symbols/symbolfile';
 import { romBytes, type CompileResult } from './testlib';
@@ -297,7 +298,7 @@ async function openProgram(command: string, args: Args, input: string): Promise<
   let debugInfo: BuildInfo | undefined;
   if (built) {
     const mainPath = path.basename(input);
-    debugInfo = { listings: built.result.listings, symbols, symbolsizes: built.result.symbolsizes, mainPath, paths: [mainPath] };
+    debugInfo = { ...buildProducts(built.result), mainPath, paths: [mainPath] };
   }
   return { target, source: input, romFile, built, symbols, debugInfo };
 }
diff --git a/src/tools/debugservice.ts b/src/tools/debugservice.ts
index a601928c..882a823d 100644
--- a/src/tools/debugservice.ts
+++ b/src/tools/debugservice.ts
@@ -10,7 +10,7 @@ import { Breakpoint, makeCondContext } from '../common/breakpoints';
 import { compileExpression } from '../common/breakcond';
 import { TreeEntry, treeChildren } from '../common/debugtree';
 import { walkStack } from '../common/stackwalk';
-import { buildDebugContext, DebugController, DebugLocation, StepGranularity, StopEvent } from '../common/debugcontroller';
+import { buildDebugContext, BuildInfo, DebugController, DebugLocation, StepGranularity, StopEvent } from '../common/debugcontroller';
 import { resolveSymbolName } from '../common/symbols/symbolfile';
 import { formatSymbolValue, MAX_SYMBOL_BYTES, SymbolValue } from '../common/symbols/symbolvalue';
 import { Granularity, Timestamp } from '../common/timeline';
@@ -74,6 +74,8 @@ export interface EvalResult {
   moved?: boolean;
 }
 
+export type { BuildInfo };
+
 export interface TimelineInfo {
   first: number;
   last: number;
@@ -81,14 +83,6 @@ export interface TimelineInfo {
   past: boolean;
 }
 
-export interface BuildInfo {
-  listings?: CodeListingMap;
-  symbols?: { [name: string]: number };
-  symbolsizes?: { [name: string]: number };
-  mainPath: string;
-  paths?: string[];
-}
-
 // how far before an address to start disassembling, per instruction wanted
 const MAX_INSN_BYTES = 4;
 
diff --git a/src/tools/testlib.ts b/src/tools/testlib.ts
index 5242359f..cf561d72 100644
--- a/src/tools/testlib.ts
+++ b/src/tools/testlib.ts
@@ -5,7 +5,8 @@
 
 import * as fs from 'fs';
 import * as path from 'path';
-import type { WorkerResult, WorkerErrorResult, WorkerMessage, BuildArgLists, BuildSymbolLists, FileData } from "../common/workertypes";
+import type { WorkerResult, WorkerErrorResult, WorkerMessage, BuildArgLists, BuildSymbolLists, FileData, BuildProducts } from "../common/workertypes";
+import { buildProducts } from "../common/workertypes";
 import { isProbablyBinary, getBasePlatform } from "../common/util";
 import { getToolForPlatform } from "../common/toolselect";
 import { FileProvider, buildWorkerMessage, resolveDependencies } from "../common/projectcore";
@@ -30,14 +31,10 @@ export interface CompileOptions {
   buildArgs?: BuildArgLists;
 }
 
-export interface CompileResult {
+export interface CompileResult extends BuildProducts {
   success: boolean;
   output?: Uint8Array | any;
   errors?: { line: number; msg: string; path?: string }[];
-  listings?: any;
-  symbolmap?: any;
-  symbolsizes?: { [sym: string]: number };
-  segments?: any;
   params?: any;
   unchanged?: boolean;
   /** every file the build read, by worker filename (verilog's $readmem reads them at load time) */
@@ -224,11 +221,8 @@ function workerResultToCompileResult(result: WorkerResult): CompileResult {
     return {
       success: true,
       output: result.output,
-      listings: (result as any).listings,
-      symbolmap: (result as any).symbolmap,
-      symbolsizes: (result as any).symbolsizes,
-      segments: (result as any).segments,
       params: (result as any).params,
+      ...buildProducts(result),
     };
   }
   return { success: false, errors: [{ line: 0, msg: 'Unknown result format' }] };
diff --git a/test/unit/testdapsession.ts b/test/unit/testdapsession.ts
index cd90896a..09a49310 100644
--- a/test/unit/testdapsession.ts
+++ b/test/unit/testdapsession.ts
@@ -19,7 +19,7 @@ async function launch(args: any = {}): Promise<DapClient> {
     const target = await loadPlatform('mw8080bw');
     await target.start();
     await target.loadROM(build.output);
-    return { target, root: ROOT, debugInfo: { listings: build.listings, symbols: build.symbolmap, symbolsizes: { _draw_char: 4, _main: 100 }, mainPath: 'game2.c' } };
+    return { target, root: ROOT, debugInfo: { listings: build.listings, symbolmap: build.symbolmap, symbolsizes: { _draw_char: 4, _main: 100 }, mainPath: 'game2.c' } };
   });
   const c = new DapClient(new EmuDebugSession(backend));
   const caps = await c.request('initialize', { adapterID: '8bitworkshop', linesStartAt1: true, columnsStartAt1: true, pathFormat: 'path' });
diff --git a/test/unit/testdebugcontroller.ts b/test/unit/testdebugcontroller.ts
index 5768e33b..63e9be6a 100644
--- a/test/unit/testdebugcontroller.ts
+++ b/test/unit/testdebugcontroller.ts
@@ -17,7 +17,7 @@ async function open(): Promise<{ t: EmuTarget, dc: DebugController }> {
   const t = await loadPlatform('mw8080bw');
   await t.start();
   await t.loadROM(build.output);
-  const dc = new DebugController(t, buildDebugContext({ listings: build.listings, symbols: build.symbolmap, mainPath: 'game2.c' }));
+  const dc = new DebugController(t, buildDebugContext({ listings: build.listings, symbolmap: build.symbolmap, mainPath: 'game2.c' }));
   return { t, dc };
 }