fix: Set viewport after updating timeouts when setting emulation - #2134

🤖 I have created a release *beep* *boop*
---


##
[1.1.0](ChromeDevTools/chrome-devtools-mcp@chrome-devtools-mcp-v1.0.1...chrome-devtools-mcp-v1.1.0)
(2026-05-26)


### 🎉 Features

* add extraHttpHeaders emulation to emulate tool
([ChromeDevTools#1176](ChromeDevTools#1176))
([6992106](ChromeDevTools@6992106))
* created cursor plugin.json setting file with release auto versioning
([ChromeDevTools#2091](ChromeDevTools#2091))
([10c8205](ChromeDevTools@10c8205))


### 🛠️ Fixes

* Apply CPU throttling to secondary CDP session
([ChromeDevTools#2092](ChromeDevTools#2092))
([3ade962](ChromeDevTools@3ade962))
* **cli:** address pid file creation issues
([ChromeDevTools#2124](ChromeDevTools#2124))
([1b51a52](ChromeDevTools@1b51a52))
* exit on stdin EOF and SIGTERM/SIGINT/SIGHUP, closing the browser
cleanly
([ChromeDevTools#2117](ChromeDevTools#2117))
([43b934c](ChromeDevTools@43b934c))
* Fix throttling info in performance trace output
([ChromeDevTools#2096](ChromeDevTools#2096))
([57f32b0](ChromeDevTools@57f32b0))
* make pageId required
([ChromeDevTools#2084](ChromeDevTools#2084))
([d751693](ChromeDevTools@d751693)),
closes
[ChromeDevTools#2052](ChromeDevTools#2052)
* remove duplicate .mcp.json
([ChromeDevTools#2095](ChromeDevTools#2095))
([dbf6ba9](ChromeDevTools@dbf6ba9))
* Set viewport after updating timeouts when setting emulation
([ChromeDevTools#2134](ChromeDevTools#2134))
([0c3ac37](ChromeDevTools@0c3ac37))
* use pinned version for plugins
([ChromeDevTools#2135](ChromeDevTools#2135))
([8ea5f09](ChromeDevTools@8ea5f09))
* use realpath for MCP roots validation
([ChromeDevTools#2127](ChromeDevTools#2127))
([176eb69](ChromeDevTools@176eb69))


### 📄 Documentation

* align coding agent examples with Antigravity
([ChromeDevTools#2094](ChromeDevTools#2094))
([ce31594](ChromeDevTools@ce31594))
* fix installation instructions for VS Code
([ChromeDevTools#2087](ChromeDevTools#2087))
([9f47df3](ChromeDevTools@9f47df3))


### 🏗️ Refactor

* remove redundant validatePath calls
([ChromeDevTools#2136](ChromeDevTools#2136))
([521c388](ChromeDevTools@521c388))

---
This PR was generated with [Release
Please](https://github.com/googleapis/release-please). See
[documentation](https://github.com/googleapis/release-please#release-please).

…omeDevTools#2134)

Tentatively addresses ChromeDevTools#2115

🤖 I have created a release *beep* *boop*
---


##
[1.1.0](ChromeDevTools/chrome-devtools-mcp@chrome-devtools-mcp-v1.0.1...chrome-devtools-mcp-v1.1.0)
(2026-05-26)


### 🎉 Features

* add extraHttpHeaders emulation to emulate tool
([ChromeDevTools#1176](ChromeDevTools#1176))
([6992106](ChromeDevTools@6992106))
* created cursor plugin.json setting file with release auto versioning
([ChromeDevTools#2091](ChromeDevTools#2091))
([10c8205](ChromeDevTools@10c8205))


### 🛠️ Fixes

* Apply CPU throttling to secondary CDP session
([ChromeDevTools#2092](ChromeDevTools#2092))
([3ade962](ChromeDevTools@3ade962))
* **cli:** address pid file creation issues
([ChromeDevTools#2124](ChromeDevTools#2124))
([1b51a52](ChromeDevTools@1b51a52))
* exit on stdin EOF and SIGTERM/SIGINT/SIGHUP, closing the browser
cleanly
([ChromeDevTools#2117](ChromeDevTools#2117))
([43b934c](ChromeDevTools@43b934c))
* Fix throttling info in performance trace output
([ChromeDevTools#2096](ChromeDevTools#2096))
([57f32b0](ChromeDevTools@57f32b0))
* make pageId required
([ChromeDevTools#2084](ChromeDevTools#2084))
([d751693](ChromeDevTools@d751693)),
closes
[ChromeDevTools#2052](ChromeDevTools#2052)
* remove duplicate .mcp.json
([ChromeDevTools#2095](ChromeDevTools#2095))
([dbf6ba9](ChromeDevTools@dbf6ba9))
* Set viewport after updating timeouts when setting emulation
([ChromeDevTools#2134](ChromeDevTools#2134))
([0c3ac37](ChromeDevTools@0c3ac37))
* use pinned version for plugins
([ChromeDevTools#2135](ChromeDevTools#2135))
([8ea5f09](ChromeDevTools@8ea5f09))
* use realpath for MCP roots validation
([ChromeDevTools#2127](ChromeDevTools#2127))
([176eb69](ChromeDevTools@176eb69))


### 📄 Documentation

* align coding agent examples with Antigravity
([ChromeDevTools#2094](ChromeDevTools#2094))
([ce31594](ChromeDevTools@ce31594))
* fix installation instructions for VS Code
([ChromeDevTools#2087](ChromeDevTools#2087))
([9f47df3](ChromeDevTools@9f47df3))


### 🏗️ Refactor

* remove redundant validatePath calls
([ChromeDevTools#2136](ChromeDevTools#2136))
([521c388](ChromeDevTools@521c388))

---
This PR was generated with [Release
Please](https://github.com/googleapis/release-please). See
[documentation](https://github.com/googleapis/release-please#release-please).

…vTools#3150)

Fixes ChromeDevTools#2966

`McpPage.emulate()` stores the new emulation settings before calling
`page.setViewport()` (intentionally, since ChromeDevTools#2134, so a
viewport-triggered reload uses the updated timeouts). When Chrome
rejects the viewport (e.g. `800.5x600x1` or `20000000x600x1`), the
rejected value stayed stored, so later responses printed `Emulating
viewport: ...` for a viewport the page doesn't have, and
`lighthouse_audit` failed when it called `restoreEmulation()`.

### Changes

- `src/McpPage.ts`: if `setViewport()` throws, put the previous viewport
back into the stored emulation settings (or drop it if there was none)
and rethrow. The order from ChromeDevTools#2134 (store settings, update timeouts, then
set the viewport) is unchanged, and the other settings applied in the
same call stay as they are.
- `tests/McpPage.test.ts`: two unit tests in which `setViewport`
rejects, one with no previous viewport and one with a previous viewport.

This changes only state handling in `McpPage`. It doesn't touch viewport
parsing in `ToolDefinition.ts`, so it doesn't overlap with ChromeDevTools#3120 /
ChromeDevTools#3124, which tighten input validation. The two changes work together:
validation rejects bad input earlier, and this keeps the stored state
consistent when Chrome still rejects a value.

### Testing

- `npm run test tests/McpPage.test.ts`: both new tests fail without the
fix (the stored viewport is `800.5x600` / `20000000x600`) and pass with
it. The file runs 74/74.
- `npm run check-format`: passes.
- Full `npm run test -- --test-concurrency=1` on Windows 11 / Node 22:
1386 passed, 1 failed (`ConfigWatcher` › follows symlinks, which needs
symlink privileges on Windows), and 6 files cancelled on the 120s file
timeout (e2e CLI daemon, `index.test`, `HeapSnapshotManager`). The same
tests fail the same way on unmodified `main` (9171f77) on this machine,
so the change doesn't cause them.