diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 554d479..33fec51 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -21,6 +21,7 @@ jobs:
       - uses: actions/setup-node@v7
         with:
           node-version: latest
+      - run: npm ci
       - run: npm test
 
   benchmark:
diff --git a/README.md b/README.md
index e852ffd..f9feeb9 100644
--- a/README.md
+++ b/README.md
@@ -88,7 +88,7 @@ Attributes set on server spans:
 | `url.path`                  | Request URL path (without query) | Always                        |
 | `url.query`                 | Query string (without `?`)       | When query string is present  |
 | `url.scheme`                | `http` or `https`                | Always                        |
-| `server.address`            | Host header value                | When `Host` header is present |
+| `server.address`            | Requested host, without the port | When `Host` header is present |
 | `network.protocol.version`  | HTTP version (e.g. `1.1`)        | Always                        |
 | `http.response.status_code` | Response status code             | When response finishes        |
 | `error.type`                | HTTP status code as string       | On 5xx responses              |
@@ -136,7 +136,7 @@ Attributes set on undici/fetch client spans:
 | --------------------------- | ------------------------- | ------------------------- |
 | `http.request.method`       | HTTP method               | Always                    |
 | `url.full`                  | Full request URL          | Always                    |
-| `server.address`            | Target origin             | Always                    |
+| `server.address`            | Target host               | Always                    |
 | `server.port`               | Target port               | Always                    |
 | `http.response.status_code` | Response status code      | When response is received |
 | `error.type`                | Status code or error name | On 4xx/5xx or errors      |
diff --git a/lib/instrumentations.js b/lib/instrumentations.js
index f10dab1..f670aec 100644
--- a/lib/instrumentations.js
+++ b/lib/instrumentations.js
@@ -83,7 +83,7 @@ function onHttpServerRequestStart({ request, response, socket }) {
   span.setAttribute('network.protocol.version', request.httpVersion || '1.1');
 
   const host = request.headers?.host;
-  if (host) span.setAttribute('server.address', host);
+  if (host) span.setAttribute('server.address', splitAuthority(host)[0]);
 
   // The span is stashed on the request so the response handlers do not
   // need a second AsyncLocalStorage lookup.
@@ -243,9 +243,9 @@ function onUndiciRequestCreate({ request }) {
   const { origin } = request;
   const path = request.path;
   if (origin) {
-    span.setAttribute('server.address', origin);
     // The origin omits the port when it is the scheme default.
     const parsed = new URL(origin);
+    span.setAttribute('server.address', parsed.hostname);
     span.setAttribute(
       'server.port',
       Number(parsed.port) || (parsed.protocol === 'https:' ? 443 : 80),
diff --git a/package-lock.json b/package-lock.json
index fa26e29..71bb80e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,12 +9,23 @@
       "version": "0.0.0",
       "license": "MIT",
       "devDependencies": {
+        "@opentelemetry/semantic-conventions": "1.43.0",
         "prettier": "3.9.10"
       },
       "engines": {
         "node": ">=26.9.0"
       }
     },
+    "node_modules/@opentelemetry/semantic-conventions": {
+      "version": "1.43.0",
+      "resolved": "https://registry.npmjs.org/@opentelemetry/semantic-conventions/-/semantic-conventions-1.43.0.tgz",
+      "integrity": "sha512-eSYWTm620tTk45EKSedaUL8MFYI8hW164hIXsgIHyxu3VobUB3fFCu5t0hQby6OoWRPsG1KkKUG2M5UadiLiVg==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "engines": {
+        "node": ">=14"
+      }
+    },
     "node_modules/prettier": {
       "version": "3.9.10",
       "resolved": "https://registry.npmjs.org/prettier/-/prettier-3.9.10.tgz",
diff --git a/package.json b/package.json
index d15c0c0..6873f9b 100644
--- a/package.json
+++ b/package.json
@@ -31,6 +31,7 @@
     "format:check": "prettier --check ."
   },
   "devDependencies": {
+    "@opentelemetry/semantic-conventions": "1.43.0",
     "prettier": "3.9.10"
   }
 }
diff --git a/test/test-http-server.js b/test/test-http-server.js
index 486802d..69e2661 100644
--- a/test/test-http-server.js
+++ b/test/test-http-server.js
@@ -48,6 +48,7 @@ describe('otel HTTP server spans', () => {
 
     assert.partialDeepStrictEqual(spanAttrs(serverSpan), {
       'http.request.method': 'GET',
+      'server.address': '127.0.0.1',
       'url.path': '/test-path',
       'http.response.status_code': '200',
     });
diff --git a/test/test-semconv.js b/test/test-semconv.js
new file mode 100644
index 0000000..de09ee6
--- /dev/null
+++ b/test/test-semconv.js
@@ -0,0 +1,80 @@
+'use strict';
+
+const assert = require('node:assert');
+const { after, before, describe, it } = require('node:test');
+// The registry of defined attribute names: the package's exports are the
+// attribute names the OpenTelemetry semantic conventions define.
+const semconv = require('@opentelemetry/semantic-conventions');
+const { flush } = require('../lib/flush');
+const { startTracing, startHTTPServer, httpGet } = require('./common/otel');
+
+const registry = new Set(
+  Object.values(semconv).filter((v) => typeof v === 'string'),
+);
+
+describe('otel semantic conventions', () => {
+  let collector;
+
+  before(async () => {
+    collector = await startTracing();
+  });
+
+  after(() => collector.close());
+
+  it('emits only attribute names the conventions define', async () => {
+    // One trace through every instrumentation shape: a server span with
+    // its query attribute, http and fetch client spans, a failed request
+    // for the error attributes, and a refused connection for the
+    // exception event attributes.
+    const ok = await startHTTPServer();
+    const failing = await startHTTPServer((req, res) => {
+      res.writeHead(500);
+      res.end();
+    });
+
+    await httpGet(ok.port, '/semconv?token=1');
+    await fetch(`http://127.0.0.1:${ok.port}/fetch`)
+      .then((res) => res.text())
+      .catch(() => {});
+    await httpGet(failing.port, '/fail');
+    await httpGet(1, '/refused').catch(() => {});
+
+    flush();
+    const payload = await collector.next();
+
+    await ok.close();
+    await failing.close();
+
+    const spans = payload.resourceSpans[0].scopeSpans[0].spans;
+    assert.ok(
+      spans.some((s) => s.kind === 2),
+      'Expected a server span',
+    );
+    assert.ok(
+      spans.some((s) => s.kind === 3),
+      'Expected client spans',
+    );
+
+    const assertDefined = (key, where) =>
+      assert.ok(
+        registry.has(key),
+        `${where} attribute "${key}" is not defined by the ` +
+          'semantic conventions',
+      );
+
+    for (const span of spans) {
+      for (const attr of span.attributes ?? []) {
+        assertDefined(attr.key, 'span');
+      }
+      for (const event of span.events ?? []) {
+        for (const attr of event.attributes ?? []) {
+          assertDefined(attr.key, 'event');
+        }
+      }
+    }
+
+    for (const attr of payload.resourceSpans[0].resource.attributes) {
+      assertDefined(attr.key, 'resource');
+    }
+  });
+});
diff --git a/test/test-undici.js b/test/test-undici.js
index 2655464..0b5c73b 100644
--- a/test/test-undici.js
+++ b/test/test-undici.js
@@ -64,7 +64,7 @@ describe('otel undici spans', () => {
 
       assert.partialDeepStrictEqual(spanAttrs(clientSpan), {
         'http.request.method': 'GET',
-        'server.address': `http://127.0.0.1:${target.port}`,
+        'server.address': '127.0.0.1',
         'server.port': String(target.port),
         'url.full': `http://127.0.0.1:${target.port}/fetch-test`,
         'http.response.status_code': '200',