self-healing-browser-mcp

An MCP server that hands an AI agent — Claude Desktop, Claude Code, Cursor, or anything that speaks MCP — a real browser to drive, with self-healing locators.

Why

The moment you let an agent automate a browser, brittle selectors bite: a data-testid gets renamed, the DOM is restructured, a button's markup changes — and the run dies on a locator not found. Agents burn tokens retrying, or just give up.

This server takes a different contract. You describe an element by whatever you know — a test id, a role + accessible name, a label, some text, a CSS selector — and it resolves the element using the most stable strategy that still works. If your preferred locator has drifted, it heals to a fallback and tells you so, instead of failing.

Related MCP server: browser-control-mcp-server

How the self-healing works

Each element tool accepts the same optional strategies. The resolver tries them in priority order and uses the first that matches exactly one visible element:

testid  →  role + name  →  label  →  placeholder  →  text  →  css  →  fuzzy (accessible-name match)

• If your first-choice strategy resolves the element, great — no heal.

• If it doesn't (renamed test id, changed structure) but a later strategy does, the result is flagged healed so you know the locator drifted and should be updated.

• If only a name is known and its casing/wording shifted, a final fuzzy pass matches the accessible name across interactive roles.

The agent "sees" the page semantically via browser_snapshot (roles + accessible names from the accessibility tree), not raw HTML or screenshots.

Demo

See it heal live — the same locator hint keeps working after a refactor deletes the element's data-testid (examples/self_healing_demo.py):

$ python examples/self_healing_demo.py
1) Original app — the preferred data-testid resolves the button:
   -> resolved via 'testid'   healed=False

2) After a refactor removed the data-testid — SAME hint, no code change:
   -> resolved via 'role'       healed=True
   -> clicked the recovered element successfully

The data-testid the agent learned is gone, but because the hint also carried the button's role and accessible name, the engine recovered the element, flagged the heal, and the element stayed clickable — no test edit, no agent retry loop.

Tools

The ... on element tools is the locator strategy set: testid, role, name, label, placeholder, text, css — all optional; pass as many as you know.

Install

From PyPI, into a virtual environment, then download the Chromium build Playwright drives:

python3 -m venv .venv
.venv/bin/pip install self-healing-browser-mcp
.venv/bin/python -m playwright install chromium

The server executable is .venv/bin/self-healing-browser-mcp (on Windows, .venv\Scripts\self-healing-browser-mcp.exe). It is only on your PATH while that venv is active, and MCP clients do not activate it, so point the client at the full path.

To work on the code, install from a clone instead (editable):

git clone https://github.com/RAJUSHANIGARAPU/self-healing-browser-mcp
cd self-healing-browser-mcp
python3 -m venv .venv
.venv/bin/pip install -e .
.venv/bin/python -m playwright install chromium

Use it from an MCP client

Option A — no venv, with uv. uvx installs the package from PyPI into a cached environment and runs it. Download Chromium once with the same Playwright version:

uvx --from self-healing-browser-mcp playwright install chromium

Claude Code:

claude mcp add self-healing-browser -- uvx self-healing-browser-mcp

Claude Desktop / Cursor (MCP servers config):

{
  "mcpServers": {
    "self-healing-browser": {
      "command": "uvx",
      "args": ["self-healing-browser-mcp"]
    }
  }
}

The first launch downloads dependencies, so the client's first connection can take a few seconds longer.

Option B — the venv you installed into. Replace /abs/path/to/.venv with the real path.

Claude Code:

claude mcp add self-healing-browser -- /abs/path/to/.venv/bin/self-healing-browser-mcp

Claude Desktop / Cursor (MCP servers config):

{
  "mcpServers": {
    "self-healing-browser": {
      "command": "/abs/path/to/.venv/bin/self-healing-browser-mcp"
    }
  }
}

Then ask your agent to, e.g., "open example.com, snapshot the page, and click the Sign in button." When a selector has drifted, the tool result will say it healed.

Configuration

How this differs from Microsoft's Playwright MCP

microsoft/playwright-mcp is the official, much broader server. Both drive Playwright and both let the agent read the page as an accessibility snapshot rather than screenshots. The differences:

Both let you change the test-id attribute (SHBM_TESTID_ATTR here, --test-id-attribute there). If you need multiple browsers, tabs, network control or screenshots, use Microsoft's server. This one is for the narrower case where an agent reuses locators across runs and you want them to survive markup changes and tell you when they drifted.

Develop

pip install -e ".[dev]"
python -m playwright install chromium
pytest

The self-healing engine (src/self_healing_browser_mcp/engine.py) is decoupled from the MCP layer and tested deterministically against in-memory HTML — no external site, no flakiness.

Releasing

Publishing to PyPI is automated with GitHub Actions via PyPI Trusted Publishing (OIDC) — no API token is stored in the repo. Every push builds and twine checks the distribution in CI, so main is always release-ready.

To cut a release:

1. Bump version in pyproject.toml, commit, and tag (git tag v0.1.1 && git push --tags).

2. Publish a GitHub Release for that tag — the Publish to PyPI workflow builds and uploads it to PyPI through the project's Trusted Publisher (workflow publish.yml, environment pypi).

License

MIT — see LICENSE.