diff --git a/packages/bundle-source/NEWS.md b/packages/bundle-source/NEWS.md
index a110edc50f..f86e77ebef 100644
--- a/packages/bundle-source/NEWS.md
+++ b/packages/bundle-source/NEWS.md
@@ -11,8 +11,8 @@
 - Adds a `-f,--format` command flag to specify other module formats.
 - Adds a new `endoScript` module format.
 - Adds a no-cache, bundle-to-stdout mode.
-- Adds a `-t,--tag` command flag to specify export/import conditions like
-  `"browser"`.
+- Adds a `-C,--condition` command flag to specify export/import conditions like
+  `"development"` or `"browser"`.
 
 # v3.2.1 (2024-03-20)
 
diff --git a/packages/bundle-source/cache.js b/packages/bundle-source/cache.js
index 6506dbfc7d..74220fa760 100644
--- a/packages/bundle-source/cache.js
+++ b/packages/bundle-source/cache.js
@@ -20,7 +20,7 @@ const { Fail, quote: q } = assert;
  * @property {number} bundleSize
  * @property {boolean} noTransforms
  * @property {ModuleFormat} format
- * @property {string[]} tags
+ * @property {string[]} conditions
  * @property {{ relative: string, absolute: string }} moduleSource
  * @property {Array<{ relativePath: string, mtime: string, size: number }>} contents
  */
@@ -53,6 +53,7 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
    * @param {object} [options]
    * @param {boolean} [options.noTransforms]
    * @param {string[]} [options.tags]
+   * @param {string[]} [options.conditions]
    * @param {ModuleFormat} [options.format]
    */
   const add = async (rootPath, targetName, log = defaultLog, options = {}) => {
@@ -61,10 +62,10 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
     const {
       noTransforms = false,
       format = 'endoZipBase64',
-      tags = [],
+      conditions = [],
     } = options;
 
-    tags.sort();
+    conditions.sort();
 
     const statsByPath = new Map();
 
@@ -93,7 +94,7 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
 
     const bundle = await bundleSource(
       rootPath,
-      { ...bundleOptions, noTransforms, format },
+      { ...bundleOptions, noTransforms, format, conditions },
       {
         ...readPowers,
         read: loggedRead,
@@ -123,7 +124,7 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
       ),
       noTransforms,
       format,
-      tags,
+      conditions,
     };
 
     await metaWr.atomicWriteText(JSON.stringify(meta, null, 2));
@@ -154,6 +155,7 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
    * @param {boolean} [options.noTransforms]
    * @param {ModuleFormat} [options.format]
    * @param {string[]} [options.tags]
+   * @param {string[]} [options.conditions]
    * @returns {Promise<BundleMeta>}
    */
   const validate = async (
@@ -167,9 +169,9 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
     const {
       noTransforms: expectedNoTransforms,
       format: expectedFormat,
-      tags: expectedTags = [],
+      conditions: expectedConditions = [],
     } = options;
-    expectedTags.sort();
+    expectedConditions.sort();
     if (!meta) {
       const metaJson = await loadMetaText(targetName, log);
       if (metaJson) {
@@ -194,15 +196,15 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
       moduleSource: { absolute: moduleSource },
       format = 'endoZipBase64',
       noTransforms = false,
-      tags = [],
+      conditions = [],
     } = meta;
-    tags.sort();
+    conditions.sort();
     assert.equal(bundleFileName, toBundleName(targetName));
     assert.equal(format, expectedFormat);
     assert.equal(noTransforms, expectedNoTransforms);
-    assert.equal(tags.length, expectedTags.length);
-    tags.forEach((tag, index) => {
-      assert.equal(tag, expectedTags[index]);
+    assert.equal(conditions.length, expectedConditions.length);
+    conditions.forEach((tag, index) => {
+      assert.equal(tag, expectedConditions[index]);
     });
     if (rootOpt) {
       moduleSource === cwd.neighbor(rootOpt).absolute() ||
@@ -250,7 +252,7 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
    * @param {object} [options]
    * @param {boolean} [options.noTransforms]
    * @param {ModuleFormat} [options.format]
-   * @param {string[]} [options.tags]
+   * @param {string[]} [options.conditions]
    * @returns {Promise<BundleMeta>}
    */
   const validateOrAdd = async (
@@ -269,7 +271,7 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
         meta = await validate(targetName, rootPath, log, meta, {
           format: options.format,
           noTransforms: options.noTransforms,
-          tags: options.tags,
+          conditions: options.conditions,
         });
         const {
           bundleTime,
@@ -277,7 +279,7 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
           contents,
           noTransforms,
           format = 'endoZipBase64',
-          tags = [],
+          conditions = [],
         } = meta;
         log(
           `${wr}`,
@@ -291,8 +293,8 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
           noTransforms ? 'w/o transforms' : 'with transforms',
           'with format',
           format,
-          'and tags',
-          JSON.stringify(tags),
+          'and conditions',
+          JSON.stringify(conditions),
         );
       } catch (invalid) {
         meta = undefined;
@@ -309,7 +311,7 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
         contents,
         noTransforms,
         format = 'endoZipBase64',
-        tags = [],
+        conditions = [],
       } = meta;
       log(
         `${wr}`,
@@ -322,8 +324,8 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
         noTransforms ? 'w/o transforms' : 'with transforms',
         'with format',
         format,
-        'and tags',
-        JSON.stringify(tags),
+        'and conditions',
+        JSON.stringify(conditions),
       );
     }
 
@@ -338,7 +340,7 @@ export const makeBundleCache = (wr, cwd, readPowers, opts) => {
    * @param {object} [options]
    * @param {boolean} [options.noTransforms]
    * @param {ModuleFormat} [options.format]
-   * @param {string[]} [options.tags]
+   * @param {string[]} [options.conditions]
    */
   const load = async (
     rootPath,
diff --git a/packages/bundle-source/src/main.js b/packages/bundle-source/src/main.js
index 4f31983c19..11bdd02c0e 100644
--- a/packages/bundle-source/src/main.js
+++ b/packages/bundle-source/src/main.js
@@ -11,7 +11,7 @@ const USAGE = `\
 bundle-source [-Tft] <entry.js>
 bundle-source [-Tft] --cache-js|--cache-json <cache/> (<entry.js> <bundle-name>)*
   -f,--format endoZipBase64*|nestedEvaluate|getExport
-  -t,--tag <tag> (browser, node, &c)
+  -C,--condition <condition> (browser, node, development, &c)
   -T,--no-transforms`;
 
 const options = /** @type {const} */ ({
@@ -33,9 +33,9 @@ const options = /** @type {const} */ ({
     short: 'f',
     multiple: false,
   },
-  tag: {
+  condition: {
     type: 'string',
-    short: 't',
+    short: 'C',
     multiple: true,
   },
   // deprecated
@@ -58,7 +58,7 @@ export const main = async (args, { loadModule, pid, log }) => {
   const {
     values: {
       format: moduleFormat = 'endoZipBase64',
-      tag: tags = [],
+      condition: conditions = [],
       'no-transforms': noTransforms,
       'cache-json': cacheJson,
       'cache-js': cacheJs,
@@ -94,7 +94,7 @@ export const main = async (args, { loadModule, pid, log }) => {
     const bundle = await bundleSource(entryPath, {
       noTransforms,
       format,
-      tags,
+      conditions,
     });
     process.stdout.write(JSON.stringify(bundle));
     process.stdout.write('\n');
@@ -125,7 +125,7 @@ export const main = async (args, { loadModule, pid, log }) => {
     await cache.validateOrAdd(bundleRoot, bundleName, undefined, {
       noTransforms,
       format,
-      tags,
+      conditions,
     });
   }
 };
diff --git a/packages/bundle-source/src/script.js b/packages/bundle-source/src/script.js
index 2e430927b9..3e08e8347b 100644
--- a/packages/bundle-source/src/script.js
+++ b/packages/bundle-source/src/script.js
@@ -37,7 +37,7 @@ export async function bundleScript(
     dev = false,
     cacheSourceMaps = false,
     noTransforms = false,
-    tags = [],
+    conditions = [],
     commonDependencies,
   } = options;
   const powers = { ...readPowers, ...grantedPowers };
@@ -70,7 +70,7 @@ export async function bundleScript(
 
   const source = await makeBundle(powers, entry, {
     dev,
-    tags,
+    conditions,
     commonDependencies,
     parserForLanguage,
     moduleTransforms,
diff --git a/packages/bundle-source/src/types.js b/packages/bundle-source/src/types.js
index 836f1b4326..087e0adab7 100644
--- a/packages/bundle-source/src/types.js
+++ b/packages/bundle-source/src/types.js
@@ -70,7 +70,7 @@ export {};
  * @property {boolean} [noTransforms] - when true, generates a bundle with the
  * original sources instead of SES-shim specific ESM and CJS. This may become
  * default in a future major version.
- * @property {string[]} [tags] - conditions for package.json conditional
+ * @property {string[]} [conditions] - conditions for package.json conditional
  * exports and imports.
  */
 
diff --git a/packages/bundle-source/src/zip-base64.js b/packages/bundle-source/src/zip-base64.js
index e7bd1e29d8..dbf7cb0089 100644
--- a/packages/bundle-source/src/zip-base64.js
+++ b/packages/bundle-source/src/zip-base64.js
@@ -22,7 +22,7 @@ const readPowers = makeReadPowers({ fs, url, crypto });
  * @param {boolean} [options.dev]
  * @param {boolean} [options.cacheSourceMaps]
  * @param {boolean} [options.noTransforms]
- * @param {string[]} [options.tags]
+ * @param {string[]} [options.condditions]
  * @param {Record<string, string>} [options.commonDependencies]
  * @param {object} [grantedPowers]
  * @param {(bytes: string | Uint8Array) => string} [grantedPowers.computeSha512]
@@ -40,7 +40,7 @@ export async function bundleZipBase64(
     dev = false,
     cacheSourceMaps = false,
     noTransforms = false,
-    tags = [],
+    conditions = [],
     commonDependencies,
   } = options;
   const powers = { ...readPowers, ...grantedPowers };
@@ -73,7 +73,7 @@ export async function bundleZipBase64(
 
   const compartmentMap = await mapNodeModules(powers, entry, {
     dev,
-    tags,
+    conditions,
     commonDependencies,
   });
 
diff --git a/packages/bundle-source/test/tags-command.test.js b/packages/bundle-source/test/tags-command.test.js
index ead4ccd88b..c0a4065ff8 100644
--- a/packages/bundle-source/test/tags-command.test.js
+++ b/packages/bundle-source/test/tags-command.test.js
@@ -40,11 +40,11 @@ const bundleSource = async (...args) => {
   return JSON.parse(bundleText);
 };
 
-test('bundle-source with --format and --tag', async t => {
+test('bundle-source with --format and --condition', async t => {
   const compartment = new Compartment();
   {
     const bundle = await bundleSource(
-      '--tag',
+      '--condition',
       'b',
       '--format',
       'endoScript',
@@ -55,7 +55,7 @@ test('bundle-source with --format and --tag', async t => {
   }
   {
     const bundle = await bundleSource(
-      '--tag',
+      '--condition',
       'a',
       '--format',
       'endoScript',