Ask an AI assistant about your EPICS control system. What is this PV reading right now? Why is it disconnected? Which operator screens show this device, and is it archived and alarm-configured? The server exposes your EPICS layer as Model Context Protocol (MCP) tools over p4p, so an assistant can answer those the way an operator would, instead of you clicking through CS-Studio, the Archiver Appliance UI and ChannelFinder by hand.
Read-only by default. set_pv_value is triple-gated: an env switch, a required regex
allowlist, and a rate limit. A value outside the record's own drive limits is refused after those
three have admitted the write, which is a further refusal and not a fourth gate. Logbook writes sit
behind their own separate gate, of six checks. The fullest statement of the posture, including what
leaves your machine, is
Safety and network posture.
Project status. Pre-1.0 and under active development. Tools and APIs may still change between minor versions, so pin one if you depend on it.
I want to try it, and I have no control system. Install it (below), then follow the
quick start: three commands, and epics-testpv serves the PV
for you, so there is nothing else to obtain. No facility, no IOC, no EPICS Base, no ChannelFinder,
no archiver.
I want to point it at my facility. The deployment guide is written for
that. It starts at epics-init, which prints a client-configuration block for one of four
deployment shapes and checks it in the same step, and it then walks the variables plane by plane,
the CA-bundle recipe for internal HTTPS, and the documented assumptions. Either way you end at
epics-doctor, which probes every configured plane read-only and tells you what your instance
actually reaches, and whether either write gate is armed and where it could write.
MCP is a small, standard protocol that lets an AI assistant (Claude, or any MCP client) call tools you expose to it. This server is such a tool provider for EPICS.
Its READ reach is decided by the launcher's EPICS search-path environment, not by this
server: the address lists, EPICS_PVA_NAME_SERVERS (TCP unicast, not subnet-bound), and the
auto-address search, which EPICS defaults to ON. Even an empty environment broadcasts PV
searches into the local subnets. The optional REST services stay off until their URLs are set.
PV write is the one reach the launcher does not decide: enabling it forces a loopback-only
search reach, and the process refuses to start otherwise.
Do not assume isolation from this document. Run epics-doctor to see what an instance actually
reaches, and read Safety and network posture.
An assistant does not have to ask: every read answer carries a reach field naming the plane
that served it and its scope, so no value can be quoted without both. The reach comes from the
configuration, not from a probe, and the field says so itself.
The server joins several planes of an EPICS installation, and everything it reports is framed in these terms. Full descriptions are in the tool reference.
| Plane | Source | Tools |
|---|---|---|
| Live | p4p (PVAccess; p4p 4.x offers no Channel Access) | get_pv_value, get_pvs, get_pv_info, monitor_pv, discover_pvs, set_pv_value |
| Registry | ChannelFinder | find_channels, list_channel_vocabulary, diagnose_connection, coverage_audit |
| History | EPICS Archiver Appliance | is_archived, get_pv_history, get_archive_info, get_appliance_info, list_archived_pvs |
| Alarm | Phoebus Alarm Logger | is_alarm_configured, get_alarm_history |
| Naming | ESS Naming Service | lookup_device_name, diagnose_connection, crossplane_check |
| Logbook | Phoebus Olog | search_logbook, get_log_entry, list_logbooks, list_tags, list_log_levels, create_log_entry, reply_to_log, update_log_entry, add_log_attachment, list_log_attachments, download_log_attachment |
| Display | .bob operator screens and .plt Data Browser trends (CS-Studio / Phoebus) |
validate_pvs, crossplane_check, coverage_audit, find_device |
| IOC | e3 st.cmd (+ optional .db) |
crossplane_check |
The Live plane is the only authority for connected or disconnected. Every other plane is explanatory, and is withheld rather than reported as a false negative when its service is not configured.
- Python 3.12+
- p4p ≥ 4.2, installed automatically. It bundles the EPICS libraries, so no separate EPICS Base build is needed for the client.
- A reachable EPICS PV. Your control system once you widen the address list, an IOC of your own, or
the synthetic one
epics-testpvserves, which needs nothing beyond this package.
From PyPI, with uv (recommended):
uv tool install epics-mcpor with pip:
pip install epics-mcpFor the development version, install straight from the repository
(uv tool install git+https://github.com/epicDirk/EPICS-MCP); from a local checkout,
uv tool install . and pip install . do the same thing.
This installs the core server: live PV access, diagnosis, and the REST-service planes, plus seven
commands (epics-mcp, epics-init, epics-testpv, epics-doctor, epics-diagnose,
epics-crossplane, epics-coverage).
The last two are display-aware and need the opi_navigation engine, which is not part of the
package: they refuse with an explanation rather than running. Everything else works without it.
See Related and roadmap.
Check the commands are on your PATH before anything else, because the failure otherwise arrives much later and somewhere unhelpful:
epics-doctor --version # or: which epics-doctor / where.exe epics-doctorEvery command answers --help and --version with its own name and the installed version, the one
a bug report asks for, on a core-only install as well. If nothing is found, add the tool directory
your installer used to your PATH (uv tool update-shell does that for uv). A current Linux
distribution refuses a system-wide pip install, so use a virtual environment or
uv tool install. If the install ends in compiler output, p4p had no prebuilt wheel for your
platform and fell back to building from source, see Compatibility.
| Page | What it answers |
|---|---|
| Quick start | Try it in three commands, with no control system: the test PV, the configuration block, and the client restart |
| Tools, CLIs, resources and prompts | What can it actually do? Every tool by plane, the standalone CLIs, the resources and prompts |
| Configuration | Every EPICS_MCP_* variable, including TLS trust and the EPICS network block |
| Safety and network posture | What is gated, what is audited, what decides network reach |
| MCP client integration | Ready-to-paste .mcp.json blocks, where they go, and the restart that finishes the job |
| Deployment guide | Bringing it up in your facility, plane by plane, with epics-doctor |
| Troubleshooting | It did not work: symptom first, from "the client says nothing" to a rejected config file, and the running-server questions after it |
| Removing it again | Uninstall and downgrade, and the four things an uninstall leaves behind |
| Write-gate contract | What every in-server write gate must satisfy, and what a gate is deliberately not |
| Operating guide | The operational cookbook: service landscape, recipes, error signatures. An assistant reaches the same text through the get_guide tool, one named section at a time, and an application through the epics-pv://guide resource |
| Architecture | The server → tools → services → clients layering and the plane model |
| Security policy | Reporting a vulnerability, and an honest statement of what the write gates are not |
| Contributing | Dev setup, the gate chain, Definition of Done |
| Known limits | What is deliberately not guarded, dated and measured, including the tempting repairs that were probed and rejected |
| Changelog | Release history |
Written and validated against a real installation at ESS: an e3 IOC over PVAccess, an Archiver Appliance, ChannelFinder, the Phoebus Alarm server and logger, and an Olog logbook. The quirks it compensates for were measured against those services, not read off a specification.
No site is hard-coded. Every service URL and network setting is an EPICS_MCP_* environment
variable, so deploying elsewhere means setting those variables, not changing code. Two defaults
carry a site-specific value (the ChannelFinder privacy allowlists), both documented as overridable
in the deployment guide.
Platforms. Installation is only as portable as p4p, which ships the EPICS libraries as
prebuilt wheels. Where a wheel exists, pip install just works; where it does not, pip falls back
to building from source, which needs a compiler and is not something this project tests.
| Platform | p4p wheel for Python 3.12+ |
Install verified |
|---|---|---|
| Linux x86_64 | yes | yes, in a clean container |
| Windows x86_64 | yes | yes, in a clean venv |
| macOS Apple Silicon | yes | not tested here |
| macOS Intel (x86_64) | yes, via the universal2 wheel (needs macOS 11+) |
not tested here |
| Linux aarch64 | no, source build | not tested here |
Services. Exercised against a local EPICS stack: an e3 test IOC (PVAccess), an EPICS Archiver
Appliance (single- or multi-instance), ChannelFinder, and the Phoebus Alarm server and logger.
Archiver topology note: in a single-JVM appliance the MGMT and retrieval webapps share a port, so
leave EPICS_MCP_ARCHIVER_RETRIEVAL_URL empty; in a split deployment MGMT (:17665) and retrieval
(:17668) are separate ports.
No version of those services is listed here, and that is deliberate. The deployment guide explains why, and what to run to answer the question for your own installation.
The gate chain is uv-based: uv sync --extra dev --locked, then
uv run pytest and uv run pre-commit run --all-files. A full local install additionally needs
--group displays for the opi_navigation PV engine, and a fresh clone needs one further command
to wire the commit-message guard, which lives outside the tree and which nothing can install for
you.
Every one of those, what CI runs and what it deliberately cannot, the Definition of done and the commit style: CONTRIBUTING.md.
Three things: what exists, what is deliberately missing, and what is only intended.
What exists. Four tools (validate_pvs, crossplane_check, coverage_audit, find_device)
and two commands (epics-crossplane, epics-coverage) join live PVs with the display plane:
the macro-expanded PV inventory of .bob operator screens and of the .plt Data Browser trends
reached from them, read through the opi_navigation PV engine. Everything else in this package,
live PVs, registry, history, alarm, naming and logbook, installs and runs without any of it.
What is deliberately missing. Those six are not available in a published install, and cannot
be made available by any flag. opi_navigation lives in a private repository, so it is wired
into a dependency group rather than advertised as an extra. A group stays out of the published
metadata, where an unreachable dependency would be a promise nobody could keep, and a direct git
reference is the one thing a package index refuses outright. The tools refuse with an explanation
instead of failing obscurely. This page names the gap rather than offering an install command
that cannot work.
What is intended, with no date attached. Two neighbouring pieces exist and are in daily use
here, both in private repositories: opi-live, a plugin that exposes a RUNNING CS-Studio, and
CS-Studio-MCP, an offline MCP server for the display files themselves. Opening the engine up is
tied to how those two hold up in practice. None of the three carries a release commitment, and
nothing on this page is a schedule. This page will say when one is published.
MIT, see LICENSE.
Independently developed EPICS MCP server, originally seeded from Jacky1-Jiang/EPICS-MCP-Server (MIT) and since rewritten on FastMCP and the p4p library, with a write-safety layer, batch operations, PV monitoring, cross-plane provenance, and OPI validation by epicDirk.