fix: trace request should show bodies from resource by Skn0tt · Pull Request #39930 · microsoft/playwright

Skn0tt · 2026-03-30T13:28:46Z

the trace I tested with had the bodies in resources
mime type is already present in headers, not needed again
response body is just as important as request body
removetrace install-skill in favour of existing skill

dgozman · 2026-03-30T13:32:51Z

packages/playwright-core/src/tools/trace/traceRequests.ts

+    }
+
+    if (body) {
+      console.log('\n  Response body');


Perhaps under an option? Bodies are large, I am not sure always printing 2000 characters for them is a net win. Tbh, same feeling for request bodies.

Alternatively, we could print the resource path on disk.

dgozman · 2026-03-30T13:33:01Z

packages/playwright-core/src/tools/trace/installSkill.ts

  const cwd = process.cwd();
  const skillSource = path.join(__dirname, 'SKILL.md');
-  const destDir = path.join(cwd, '.claude', 'playwright-trace');
+  const destDir = path.join(cwd, '.claude', 'skills', 'playwright-trace');


Copilot

Pull request overview

Updates the Playwright Trace CLI’s trace request output to include request/response bodies even when they’re stored as trace resources, and adjusts the trace CLI test fixtures accordingly.

Changes:

Add CLI output for request body (loaded from postData._sha1/_file resources when present).
Add CLI output for response body (loaded from content._sha1/_file resources when present).
Extend MCP trace CLI fixtures/tests to generate and assert a POST request with bodies, and adjust trace install-skill destination path.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
tests/mcp/trace-cli.spec.ts	Adds an assertion that `trace request` prints both request and response bodies.
tests/mcp/trace-cli-fixtures.ts	Adds a `/feedback` endpoint and a POST fetch to ensure bodies are present in the trace.
packages/playwright-core/src/tools/trace/traceRequests.ts	Loads bodies from trace resources and prints request/response bodies in `trace request`.
packages/playwright-core/src/tools/trace/installSkill.ts	Installs the trace skill under `.claude/skills/playwright-trace`.

Copilot · 2026-03-30T13:33:33Z

packages/playwright-core/src/tools/trace/traceRequests.ts

+      if (blob)
+        body = await blob.text();


blob.text() converts the entire attached request payload to a string before truncation, which can be very expensive for large bodies; consider reading only the first ~2000 bytes/chars (e.g. via blob.slice(...)) and using blob.size to decide whether to append ....

Suggested change

if (blob)

body = await blob.text();

if (blob) {

const maxPreviewBytes = 2000;

const slice = blob.slice(0, maxPreviewBytes);

body = await slice.text();

if (blob.size > maxPreviewBytes)

body += '...';

}

Copilot · 2026-03-30T13:33:34Z

packages/playwright-core/src/tools/trace/traceRequests.ts

+    let body = r.response.content.text;
+    const resource = r.response.content._sha1 ?? r.response.content._file;
+    if (resource) {
+      const blob = await trace.loader.resourceForSha1(resource);
+      if (blob)
+        body = await blob.text();
+    }


Same concern for response bodies: blob.text() loads the full response into a string even though only the first 2000 chars are printed; slicing the blob before decoding avoids large extra allocations for big resources.

Skn0tt · 2026-03-31T07:07:47Z

packages/playwright-core/src/tools/cli-client/skill/references/tracing.md

 playwright-cli tracing-stop
+
 # Open trace to see DOM state when click was attempted
+npx playwright trace open TODO


i'll double-check all these scripts before merging

dgozman · 2026-03-31T07:14:53Z

packages/playwright-core/src/tools/trace/installSkill.ts

-
-export async function installSkill() {
-  const cwd = process.cwd();
-  const skillSource = path.join(__dirname, 'SKILL.md');


Shouldn't this SKILL.md file be removed?

dgozman · 2026-03-31T07:15:05Z

packages/playwright-core/src/tools/trace/traceRequests.ts

-    if (r.request.postData.text) {
+    const resource = r.request.postData._sha1 ?? r.request.postData._file;
+    if (resource) {
+      console.log(`    ${path.resolve(trace.model.traceUri, 'resources', resource)}`);


Relative to cwd please.

dgozman · 2026-03-31T07:15:14Z

packages/playwright-core/src/tools/trace/traceRequests.ts

+    const resource = r.response.content._sha1 ?? r.response.content._file;
+    if (resource) {
+      console.log('\n  Response body');
+      console.log(`    ${path.resolve(trace.model.traceUri, 'resources', resource)}`);


Relative to cwd here as well.

dgozman · 2026-03-31T07:17:53Z

packages/playwright-core/src/tools/cli-client/skill/references/tracing.md

 Capture detailed execution traces for debugging and analysis. Traces include DOM snapshots, screenshots, network activity, and console logs.

-## Basic Usage
+## Recording a Trace


Let's not merge the skill here yet, make a separate PR for it please.

github-actions · 2026-03-31T08:33:48Z

Test results for "MCP"

1 failed
❌ [msedge] › mcp/files.spec.ts:106 › clicking on download link emits download @mcp-windows-latest

6295 passed, 360 skipped

Merge workflow run.

…rom resource

…rce (#39951) Co-authored-by: Simon Knott <info@simonknott.de>

Skn0tt requested review from Copilot and dgozman March 30, 2026 13:28

Skn0tt changed the title ~~fix: trace requests should show bodies from resource~~ fix: trace request should show bodies from resource Mar 30, 2026

Copilot started reviewing on behalf of Skn0tt March 30, 2026 13:29 View session

dgozman reviewed Mar 30, 2026

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Skn0tt commented Mar 31, 2026

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fix: trace request should show bodies from resource

549bc99

Skn0tt force-pushed the trace-feedback branch from 14c704b to 549bc99 Compare March 31, 2026 07:56

dgozman approved these changes Mar 31, 2026

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Skn0tt merged commit 9c68b52 into microsoft:main Mar 31, 2026
10 of 11 checks passed

dgozman pushed a commit to dgozman/playwright that referenced this pull request Mar 31, 2026

cherry-pick(microsoft#39930): fix: trace request should show bodies f…

371af57

…rom resource

dgozman added a commit that referenced this pull request Mar 31, 2026

cherry-pick(#39930): fix: trace request should show bodies from resou…

c23fe70

…rce (#39951) Co-authored-by: Simon Knott <info@simonknott.de>

-      if (blob)
-        body = await blob.text();
+      if (blob) {
+        const maxPreviewBytes = 2000;
+        const slice = blob.slice(0, maxPreviewBytes);
+        body = await slice.text();
+        if (blob.size > maxPreviewBytes)
+          body += '...';
+      }

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Skn0tt commented Mar 30, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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github-actions bot commented Mar 31, 2026

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Skn0tt commented Mar 30, 2026 •

edited

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