Add a get_heapsnapshot_object_details MCP tool which lets the agent
query all known information about a node in the heap snapshot.
Co-authored-by: Dominik Inführ <dinfuehr@chromium.org>
Emits native contexts and their sizes with the get_heapsnapshot_summary
MCP tool. This should help the agent get an overview about which native
contexts consume the most memory.
Co-authored-by: Dominik Inführ <dinfuehr@chromium.org>
This exposes DevTools named filters in get_heapsnapshot_details and
get_heapsnapshot_class_nodes tools. This allows the client to list e.g.
all objects retained through detached DOM objects.
Co-authored-by: Dominik Inführ <dinfuehr@chromium.org>
Instead of two separate MCP tools, we can have one instead which takes
classIndex as optional argument.
Co-authored-by: Dominik Inführ <dinfuehr@chromium.org>
This commit adds two MCP tools for comparing heap snapshots.
`compare_heapsnapshot_summary` compares two memory snapshot and returns
which classes have new/deleted objects.
`compare_heapsnapshot_class_nodes` can then be used to list the object
ids added and deleted for a specific class.
Co-authored-by: Dominik Inführ <dinfuehr@chromium.org>
Adding the get_heapsnapshot_dominators MCP tool to show the dominators
for a given node. In combination with get_heapsnapshot_retaining_paths
this should help understand what keeps an object reachable and thus
alive.
Co-authored-by: Dominik Inführ <dinfuehr@chromium.org>
Co-authored-by: Nicholas Roscino <nroscino@google.com>
This PR adds the get_heapsnapshot_edges MCP tool. Agents can use it to
look at the outgoing edges for a specifc object.
Co-authored-by: Dominik Inführ <dinfuehr@chromium.org>
This PR adds the `get_heapsnapshot_retaining_paths` MCP tool. This can
be used to find the paths from the target object to the GC roots which
keep that object alive.
Co-authored-by: Dominik Inführ <dinfuehr@chromium.org>
Updates the flag for the memory tooling to remove the experimental bit
(keep alias for backwards compatibility).
And updates the SKILLs to reflected the update names and point to the
available tools.
Q: Should it be called `take_heapsnapshot` or `take_heap_snapshot`?
This commit adds the close_heapsnapshot MCP tool such that the coding
agent can close heap snapshots again.
Co-authored-by: Dominik Inführ <dinfuehr@chromium.org>
Co-authored-by: Nicholas Roscino <nroscino@google.com>
## Summary
Extend the existing `emulate` tool with an `extraHTTPHeaders` parameter
that calls Puppeteer's `page.setExtraHTTPHeaders()` (which uses CDP
`Network.setExtraHTTPHeaders` under the hood).
Closes#1175
## Approach
Per [feedback from
@natorion](https://github.com/ChromeDevTools/chrome-devtools-mcp/issues/1175#issuecomment-4097587153),
this integrates into the existing `emulate` tool rather than adding a
standalone tool. The `emulate` tool is already the central hub for
page-level state modifications (userAgent, viewport, networkConditions,
geolocation, colorScheme), and custom HTTP headers fit naturally
alongside them. This also avoids increasing the MCP tool count and LLM
token overhead.
## Changes
- **`src/types.ts`** — Added `extraHTTPHeaders?: Record<string, string>`
to `EmulationSettings`
- **`src/tools/emulation.ts`** — Added `extraHTTPHeaders` as an optional
zod parameter on the `emulate` tool
- **`src/McpContext.ts`** — Added handler logic in the `emulate()`
method:
- Calls `page.setExtraHTTPHeaders()` when `extraHTTPHeaders` is provided
- Clears from settings when an empty `{}` is passed
- Preserves existing headers when the param is **omitted** (unlike other
emulation settings that reset when omitted) — prevents
`emulate({colorScheme: "dark"})` from accidentally clearing
previously-set headers
- **`tests/tools/emulation.test.ts`** — Added 5 test cases:
1. Sets extra headers on requests
2. Clears headers with `{}`
3. Headers persist across navigations
4. Does not affect other emulation settings
5. Reports correctly per-page (new page has no headers)
## Use Case
This enables setting custom HTTP headers on **all** requests — including
the initial document navigation and `<script>` tag loads — which
`initScript` cannot do since it runs after the document is already
fetched.
## Usage
```js
// Set headers
emulate({ extraHTTPHeaders: { "X-Custom": "value", "Authorization": "Bearer token" } })
// Clear headers
emulate({ extraHTTPHeaders: {} })
// Combine with other emulation settings
emulate({ extraHTTPHeaders: { "X-Branch": "feature-1" }, userAgent: "MyBot/1.0" })
```
---------
Co-authored-by: Alex Rudenko <alexrudenko@chromium.org>
Co-authored-by: Nicholas Roscino <nroscino@google.com>
Update the tools to all include the `heapsnapshot` term for easier
handling.
Renames UID to ID to reduce confusion with the snapshot UIDs.
Renames Id to NodeId to better differentiate from the base Id.
Remove EdgeIndex as it was not useful.
Closes:
https://github.com/ChromeDevTools/chrome-devtools-mcp/issues/1970
- add a message about successful configuration
- add a message about the currently emulated geolocation
- switch to comma separate format instead of `x` separator.
Tested with https://www.audero.it/demo/geolocation-api-demo.html
## Summary
Adds an optional `filePath` parameter to `evaluate_script` that saves
the script output to a file instead of returning it inline.
Refs #153
## Motivation
Issue #153 requested `filePath` support for `take_snapshot` and
`evaluate_script`. `take_snapshot` was addressed in #463. PR #248
previously attempted this but was closed due to conflicts. This PR
implements the same feature on the current codebase, completing the
remaining piece.
## Changes
- Add optional `filePath` parameter to the `evaluate_script` schema
- Add `context.validatePath(filePath)` call for path validation
- Pass `{filePath, context}` options to `performEvaluation()`
- In `performEvaluation()`: when `filePath` is provided, save output via
`context.saveFile()` with `.json` extension; otherwise return inline as
before
- Update `docs/tool-reference.md` via `npm run docs:generate`
- Add unit test for file output
## Key design decisions
- **Same pattern as existing tools**: Follows the `context.saveFile()`
pattern established by `take_snapshot` (#463), `take_screenshot`,
`get_network_request` (#795), and performance tools (#686).
- **Minimal change surface**: Only `performEvaluation()` gains an
optional `options` parameter. No new interfaces or abstractions.
- **Backwards compatible**: `filePath` is optional. When omitted,
behavior is identical to before.
## Testing
**Unit test added** (`tests/tools/script.test.ts`):
- Call `evaluate_script` with `filePath` set to a temp file
- Assert response contains "Output saved to"
- Assert file content matches the JSON-serialized return value
- Clean up temp file in `finally` block
**Manual testing performed**:
- `() => document.title` with `filePath: /tmp/test.json` → file contains
`"Example Domain"`
- `() => document.title` without `filePath` → inline ```json block
returned (no regression)
- `() => Array.from({length: 100}, ...)` with `filePath` → 100-item
array saved correctly
- `filePath` pointing to non-existent directory → directory
auto-created, file saved
- Relative path (`test.json`) → resolved to CWD, absolute path shown in
response
- Function that throws → error returned, no partial file created
- Existing file as `filePath` → file overwritten completely
---------
Co-authored-by: Alex Rudenko <alexrudenko@chromium.org>
Fixes#1942
Verified using `npm run eval --
scripts/eval_scenarios/fill_select_and_checkboxes_test.ts`
Without this change, I observed 7 runs using fill_form for all controls
at once, 14 runs using click to select checkboxes and 10 runs that did
nothing (total 31 runs)
After this change: 9 fill_form using runs (passes), 1 click based
approach and 10 no-attempt fails (20 runs total)
Depending how we count the no-attempt runs, its either increase from 23%
to 45% or 33% to 90% in eval pass rate.
Co-authored-by: Piotr Paulski <piotrpaulski@chromium.org>
Enables "third-party developer tools" feature. This allows the inspected
web page to expose tools which provide debugging information to Chrome
DevTools for Agents.
Third-party developer tools enable web applications to expose internal
state, component hierarchies, or specific debug data that cannot be
deduced through static analysis. This allows Chrome DevTools for Agents
to provide richer, more actionable context to AI agents during debugging
sessions.
2 additional tools are enabled in Chrome DevTools for Agents for
interacting with third-party developer tools:
`list_3p_developer_tools()` and `execute_3p_developer_tool`.
Code changes in this PR:
- Rename "in-page tools" to "third-party developer tools"
- Unhide
- Make available in CLI
- Add documentation
Extracting WebMCP tools into a separate category for better grouping in
the docs. This changes `--experimentalWebmcp` to
`--categoryExperimentalWebmcp` to align with other experimental
categories. Debugging category was not a good fit since the tools
provided by WebMCP are not necessarily used for debugging.
cc @beaufortfrancois
This refactors the code to extract the Id logic from the PageCollector
and provide it in the heapsnapshot.
We need to use an UID as we need the internal ClassKey to query the
heapsnapshot, but that is a strange string (usually looking like
`,ClassName`) which may get the LLM confused as we use comma separated
output.
Provide a argument to LLM to handle dialogs that come up during code
execution.
---------
Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>
## Summary
This PR fixes several documentation and skill-reference issues across
the repo to improve accuracy and reduce confusion in implementation and
troubleshooting workflows.
## Changes
- corrected CLI examples in skill docs
- fixed the documented argument order for `performance_analyze_insight`
- updated the memory leak fallback script path
- corrected generated tool reference wording by updating the
source-of-truth tool descriptions
---------
Co-authored-by: ojonesjr <50652264+ojonesjr@users.noreply.github.com>
## Summary
Fix `chrome-devtools start` so it no longer implicitly enables
`isolated` when `--userDataDir` is provided.
Previously, the CLI wrapper always defaulted `isolated` to `true` for
`start`, which caused `userDataDir` and `isolated` to conflict even when
the user only specified `--userDataDir`. This made it impossible to
start the CLI daemon against a persistent browser profile.
## Changes
- Update `chrome-devtools start` default handling in
`src/bin/chrome-devtools.ts`
- only default `isolated=true` when `userDataDir` is not set
- Clarify the `isolated` CLI description to document the conditional
default
- Update `docs/cli.md` to reflect that:
- `headless` is enabled by default
- `isolated` is enabled by default unless `--userDataDir` is provided
- Fix a small error message typo
## Why
This matches the intended semantics of the flags:
- `--isolated` means use a temporary user data dir
- `--userDataDir` means use a persistent, explicit user data dir
If the user passes `--userDataDir`, the CLI should not also implicitly
enable `isolated`.
## Testing
- Ran:
- `npm test -- tests/cli.test.ts`
- `npm test -- tests/e2e/chrome-devtools.test.ts`
Added an e2e regression test in `tests/e2e/chrome-devtools.test.ts` to
verify that:
- `chrome-devtools start --userDataDir <temp dir>` succeeds
- the CLI no longer fails with `Arguments userDataDir and isolated are
mutually exclusive`
- the daemon starts successfully when `userDataDir` is provided
## Summary
When installing `chrome-devtools-mcp` as a Claude Code plugin (from the
official Anthropic marketplace or via `/plugin marketplace add`), the
plugin system clones the repository using HTTPS
(`https://github.com/ChromeDevTools/chrome-devtools-mcp.git`). In
environments where outbound HTTPS connectivity to GitHub is restricted —
such as servers behind corporate firewalls, restrictive proxy
configurations, or hosts with port 443 blocked — this clone operation
fails with a timeout:
```
chrome-devtools-mcp@claude-plugins-official: Failed to download/cache plugin chrome-devtools-mcp:
Failed to clone repository: Cloning into '...'...
fatal: unable to access 'https://github.com/ChromeDevTools/chrome-devtools-mcp.git/':
Failed to connect to github.com port 443 after 136078 ms: Couldn't connect to server
```
This is a real-world scenario encountered on production Linux servers
where SSH to GitHub (port 22) works but HTTPS (port 443) is blocked or
unreliable. The Claude Code plugin marketplace
(`anthropics/claude-plugins-official`) specifies the HTTPS URL as the
plugin source, and users have no way to override this URL within the
plugin system itself.
## Changes
### `docs/troubleshooting.md`
Added a new troubleshooting section **Claude Code plugin installation
fails with `Failed to clone repository`** under Specific problems that
documents:
- **The exact error message** users encounter, making it searchable
- **Root cause explanation**: restricted HTTPS connectivity, firewalls,
proxy configs
- **Workaround 1 — SSH redirect**: Using `git config --global
url."git@github.com:".insteadOf "https://github.com/"` to transparently
redirect all GitHub HTTPS git operations to use SSH
- **Workaround 2 — CLI installation**: Using `claude mcp add
chrome-devtools --scope user npx chrome-devtools-mcp@latest` to install
the MCP server via npm/npx instead of git clone
### `README.md`
Added a `[!TIP]` callout in the Claude Code **Install as a Plugin**
section that cross-references the troubleshooting guide.
## Motivation
The HTTPS clone URL for this plugin is defined in the Anthropic official
plugin marketplace, not in this repository. Since users cannot change
the marketplace URL configuration, the most actionable fix from this
repository's side is to document the issue and provide clear
workarounds.
## Test plan
- [x] `npm run check-format` passes (eslint + prettier)
- [x] `npm run gen` produces no unexpected diff (auto-generated docs
unchanged)
- [x] Documentation-only change — no code, tool, or schema modifications
- [x] Markdown anchor link in README TIP callout correctly references
the troubleshooting section heading
- [x] Both workaround commands verified in the environment where this
issue was encountered
Added solutions for MCP server connection issues on Windows 10,
including using cmd and absolute path for npx.
---------
Co-authored-by: Alex Rudenko <OrKoN@users.noreply.github.com>
Co-authored-by: Alex Rudenko <alexrudenko@chromium.org>
Addresses cases where DevTools MCP tools were not consistently picked up
from natural language prompts by improving tool descriptions and
metadata.
Validation:
Tested locally across multiple prompts related to LCP and page
performance.
MCP tools were selected more consistently after the description updates.
Refs #940
---------
Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Alex Rudenko <OrKoN@users.noreply.github.com>
Co-authored-by: Nikolay Vitkov <34244704+Lightning00Blade@users.noreply.github.com>
Co-authored-by: Alex Rudenko <alexrudenko@chromium.org>
- **feat: add troubleshooting skill definition and expand documentation
with details on autoConnect timeouts and extension debugging
conflicts.**
- **docs: Simplify troubleshooting skill instructions by removing
explicit tool mentions and updating the troubleshooting guide link.**
- **docs: Update troubleshooting guide to recommend and correct usage of
`--logFile` for capturing debug logs.**
- **docs: Enhance troubleshooting guide with 'Tool not found' error,
`--autoConnect` Chrome 144+ requirement, and `startup_timeout_ms` tip
for Windows.**
- **docs: Clarify that Chrome 144+ must be running for `--autoConnect`
and add a verification step for remote debugging.**
- **feat: Add an initial troubleshooting step to read and interpret MCP
configuration, renumbering subsequent steps.**
- **docs: Add detailed troubleshooting steps for `Could not find
DevToolsActivePort` and other common connection errors.**
- **docs: Add troubleshooting guidance for empty profile creation due to
typos or misconfiguration.**
Dominik Inführ