Momentic’s MCP server exposes tools that let agents browse, edit, create, and
run tests with a live browser directly from your editor.
Requires Momentic CLI 2.54.0 or later.
Common workflows
- Implement from executable specs. Use
momentic-spec before changing
user-visible behavior so the affected Momentic tests capture the intended
product behavior and validate the finished implementation.
- Author and extend coverage. Use
momentic-test to create tests, steps,
and modules against a live browser. Use momentic-mobile-test for Android and
iOS.
- Understand a branch failure. Use
momentic-maintain to find runs for the
branch, inspect the saved classifications and run evidence, and identify the
earliest point where behavior diverged.
- Investigate failures on main. DevX and on-call engineers can group recent
failures by status or classification, inspect representative runs, and
distinguish application regressions from test, environment, and Momentic
issues.
- Deflake tests and reduce latency. Find quarantined, recovered, and
retry-heavy runs, then repair unstable tests and reduce time spent in failure
recovery. Branch, classification, and minimum-attempt filters help prioritize
repeated failure patterns.
Prerequisites
- Momentic CLI installed locally (MCP runs on your machine)
- A project with a valid
momentic.config.yaml
- A
MOMENTIC_API_KEY available to the MCP process (most editors do not
inherit your shell environment)
Setup instructions
General
Momentic’s MCP is a local stdio server. Every editor ultimately runs:
For mobile testing, substitute momentic-mobile mcp. See
momentic mcp and
momentic-mobile mcp for every
supported flag (headful browser, pixel ratio, daemon mode, etc.).
Along with the server, install the Momentic skills for your editor. Skills
give agents explicit operating guidance so they don’t make malformed tool calls:
momentic-test: how to build reliable tests, steps, and modules
momentic-spec: how to write affected tests before product changes
momentic-maintain: how to investigate branch and main failures, audit
classifications, deflake quarantined or recovered tests, reduce retries, and
repair durable test issues
After registering the server with one of the clients below, restart the client
and start a new chat. Ask the agent which MCP tools are available. You should
see momentic_* tools such as momentic_get_artifacts. If they do not appear,
fully restart the client.
Claude Code
Register the server:
Verify with claude mcp list. On native Windows, wrap with cmd /c:
Pass MOMENTIC_API_KEY via the CLI’s --env flag or by running the command
from a shell that already has it exported. See
Claude Code MCP docs
for scoping and auth options.
Restart Claude Code and run /mcp to confirm the server is active.
Codex
Register the server:
The command saves the entry to ~/.codex/config.toml. For project-scoped
configs, edit .codex/config.toml in a trusted project. See
Codex MCP docs for env vars and
timeouts.
Restart Codex, then run /mcp in the TUI to verify.
Cursor
Open the command palette, select View: Open MCP Settings, click Add a new
Custom MCP server, then paste and restart Cursor:
Devin
Follow the dedicated Devin integration page. Devin
requires additional machine-configuration steps so it can install browsers, set
ANDROID_HOME / JAVA_HOME, and pre-install skills before MCP starts.
OpenCode
Edit opencode.json in your project root or ~/.config/opencode/:
VS Code (Copilot)
Open the command palette, select MCP: Add Server, pick Command (stdio),
then paste:
Name the server momentic when prompted. Then add MOMENTIC_API_KEY to the
generated entry in mcp.json:
Your org may need to allow MCP. Copilot only exposes MCP in agent mode.
Other clients
Any MCP-compatible client can launch the server with:
- Command:
npx
- Arguments:
momentic mcp --config /absolute/path/to/momentic.config.yaml
- Env:
MOMENTIC_API_KEY=your-api-key
Install skills
After registering the MCP server with your editor, install the Momentic skill
files from your project root:
Invoke the skill
Some agents load installed skills on their own, but many skip them unless you
name the skill in the prompt. Invoke skills with a slash prefix, as the examples
below show. For agents without slash commands, ask for the skill by name.
Authorship
Use momentic-test to create or extend Momentic tests:
Use momentic-mobile-test for Android and iOS. Naming the skill keeps the agent
on Momentic’s test format and MCP workflow instead of hand-rolling browser
automation.
Maintenance
Use momentic-maintain to understand failures on a branch or main, review and
challenge saved classifications, deflake quarantined or recovered tests, reduce
retries, and repair stale test steps while preserving the intended behavior:
Spec-driven development
Once your repo is on the simplified format, Momentic tests are readable enough
to double as product specs. Invoke momentic-spec when implementing a feature
so the agent creates or updates the smallest set of affected Momentic tests
before changing product code:
To make this the default behavior for your repository, also add a spec-driven
section to your AGENTS.md (or .cursor/rules, etc.):
See Agentic testing for more on act and AI
action V3.
Usage tips
- Model: use the newest model your editor offers.
High reasoning gives the
best results; Medium is about 20% faster with some quality loss.
- Invoke the relevant skill explicitly when authoring, maintaining, or
changing product behavior.
- Be specific in prompts. For exploratory runs, include a step limit.
- Let sessions terminate: the agent calls
momentic_session_terminate to
close the browser. Hard-stopping your editor leaks browser processes.
- Gitignore
.momentic-mcp/. MCP stores screenshots, videos, and traces
there.
- Long-running steps:
momentic_run_step returns within 30 seconds. If the
step range hasn’t finished, it returns a stepRunnerId that you can poll with
momentic_poll_runner. Pass an optional timeoutSeconds (0-30, default 0) to
hold the poll open briefly instead of busy-polling.