openBIS

A Model Context Protocol server that exposes openBIS (via pyBIS) to LLM-based agents such as Claude.

The agent can browse spaces / projects / experiments / samples / datasets, inspect the schema (sample types, dataset types, vocabularies, property types), list and download dataset files, and — if explicitly enabled — create, update, and delete entities.

Status

Read-only operation works against a real openBIS instance today (tested against openbis.imm.rwth-aachen.de). Write operations are implemented but disabled by default; enable them with OPENBIS_MCP_ALLOW_WRITE=1 once you've verified the agent's behaviour on a non-production space.

Tools

Group	Tool	Purpose
session	get_server_info	URL, server version, MCP server version, write state
session	whoami	Authenticated user + session active flag
browse	list_spaces	All spaces visible to the user
browse	list_projects	Filter by space
browse	list_experiments	Filter by space / project / type
browse	list_samples	Filter by space / project / experiment / type
browse	list_datasets	Filter by space / project / experiment / sample / type
browse	get_entity	Full metadata for one entity (any kind)
search	search_samples	Property-based search with optional type/space restriction
search	search_datasets	Same shape, for datasets
schema	list_sample_types	All sample (object) types
schema	list_dataset_types	All dataset types
schema	list_experiment_types	All experiment (collection) types
schema	list_vocabularies	Controlled vocabularies
schema	get_property_types	Global list, or properties assigned to one type
files	list_dataset_files	File listing inside a dataset (no download)
files	download_dataset_file	Download one file to a local directory
write*	create_project	New project under a space
write*	create_experiment	New experiment under a project
write*	create_sample	New sample, optionally with parents/properties
write*	create_dataset	Upload local files as a new dataset
write*	update_sample	Update properties / add or remove parent–child links
write*	update_dataset	Update properties
write*	delete_entity	Delete by kind+identifier; non-empty reason required
s3	get_s3_status	S3 configuration status (bucket, region, DMS code)
s3†	create_s3_linked_dataset	Upload file to S3; register as LINK-kind dataset
s3	generate_s3_download_url	Fresh presigned S3 GET URL for a given object key

* write tools require OPENBIS_MCP_ALLOW_WRITE=1. See Enabling write access below.

† also requires OPENBIS_MCP_ALLOW_WRITE=1.

Configuration

The server reads connection details from environment variables. Provide credentials in one of three ways: a personal access token, a file containing one, or username + password.

Variable	Required?	Purpose
OPENBIS_URL	yes	Base URL, e.g. https://openbis.imm.rwth-aachen.de
OPENBIS_TOKEN	one of the three	Personal access token (PAT). Preferred.
OPENBIS_TOKEN_FILE	credential options	Path to a file holding the raw token (e.g. ~/.pybis/<host>.token). Used only if OPENBIS_TOKEN is empty.
OPENBIS_USERNAME + OPENBIS_PASSWORD	is required	Used only if neither token variable is set.
OPENBIS_VERIFY_CERTIFICATES	no	Set to false for self-signed dev certs. Default true.
OPENBIS_MCP_ALLOW_WRITE	no	Set to 1 to enable create/update/delete tools. Default off.

S3 storage configuration

S3 storage support enables storing dataset files in an S3-compatible object store while only keeping metadata (and a presigned download URL) in openBIS. This follows the approach of pybis_aixtended from pyiron/pyiron_rdm.

Install the extra dependencies first:

pip install -e ".[s3]"

Then configure via environment variables or an INI config file:

Environment variables:

Variable	Required?	Purpose
S3_ACCESS_KEY	yes	S3 access key ID
S3_ACCESS_SECRET	yes	S3 secret access key
S3_BUCKET	yes	Bucket name
S3_DMS_CODE	yes	openBIS External Data Management System code (set up by admin)
S3_REGION	no	AWS region (default: eu-central-1)
S3_ENDPOINT_URL	no	Custom endpoint for non-AWS stores
S3_ENDPOINT_PORT	no	Optional port suffix for the endpoint
S3_CONFIG_FILE	no	Path to an INI config file (overrides individual env vars)

INI config file (same format as pybis_aixtended):

[s3]
s3_region = eu-central-1
s3_endpoint_url = https://s3.example.com
s3_endpoint_port = 443
s3_access_key = AKID...
s3_access_secret = secret
s3_bucket = my-bucket

[openbis]
dms_code = MY_DMS

Point to it with S3_CONFIG_FILE=/path/to/s3_config.ini.

Note: The S3 DMS must be registered in openBIS by an instance admin before datasets can be linked. get_s3_status shows whether the server can see it; create_s3_linked_dataset requires OPENBIS_MCP_ALLOW_WRITE=1.

A template lives in .env.example. Never commit a populated .env — .gitignore excludes it.

Setting the variables

One-shot, in your shell (the agent will inherit them):

export OPENBIS_URL=https://openbis.imm.rwth-aachen.de
export OPENBIS_TOKEN=your-token-here

From a token file (matches pyBIS's own convention — pybis saves tokens to ~/.pybis/<host>.token after o.login(..., save_token=True)):

export OPENBIS_URL=https://openbis.imm.rwth-aachen.de
export OPENBIS_TOKEN_FILE=~/.pybis/openbis.imm.rwth-aachen.de.token

Inside the MCP client config — preferred, because the env vars are scoped to the MCP server process and don't leak into your interactive shell. Example for Claude Code is shown below; Claude Desktop syntax is similar.

Getting a personal access token

In the openBIS web UI: User menu → Personal Access Tokens → Create. Choose a generous expiry (e.g. 90 days) and copy the resulting string — it is shown only once. Place it in OPENBIS_TOKEN, or write it to ~/.pybis/<host>.token (single line, no quotes) and use OPENBIS_TOKEN_FILE.

Install

Requires Python 3.10+.

git clone https://github.com/biterik/openbis-mcp-server.git
cd openbis-mcp-server
python -m venv .venv
source .venv/bin/activate
pip install -e ".[dev]"

This installs the openbis-mcp-server console script.

Run

Stand-alone (for testing — speaks MCP over stdio, expects an MCP client on the other end):

export OPENBIS_URL=https://openbis.imm.rwth-aachen.de
export OPENBIS_TOKEN=...
openbis-mcp-server

In normal use you don't run it manually; an MCP client (Claude Code, Claude Desktop, ...) launches it as a subprocess.

Register with Claude Code

Claude Code's CLI manages MCP servers in ~/.claude.json (user scope) or in the per-project .mcp.json. Use the claude mcp add command rather than editing the JSON by hand.

Read-only registration (recommended starting point):

claude mcp add openbis --scope user \
  --env OPENBIS_URL=https://openbis.imm.rwth-aachen.de \
  --env OPENBIS_TOKEN_FILE=$HOME/.pybis/openbis.imm.rwth-aachen.de.token \
  -- /absolute/path/to/.venv/bin/openbis-mcp-server

The -- separates Claude Code's flags from the command Claude Code will launch. Use the absolute path to the openbis-mcp-server executable in your virtualenv so Claude Code doesn't depend on your shell's PATH.

Verify:

claude mcp list
# openbis: /abs/path/.venv/bin/openbis-mcp-server - ✓ Connected

Restart Claude Code after registration so it picks up the new server. The tools then appear under names like mcp__openbis__list_spaces, mcp__openbis__get_entity, etc.

Enabling write access

Write tools (create_*, update_*, delete_entity) raise an error unless OPENBIS_MCP_ALLOW_WRITE=1 is set in the server's environment. To enable, re-register with the extra env var:

claude mcp remove openbis --scope user
claude mcp add openbis --scope user \
  --env OPENBIS_URL=https://openbis.imm.rwth-aachen.de \
  --env OPENBIS_TOKEN_FILE=$HOME/.pybis/openbis.imm.rwth-aachen.de.token \
  --env OPENBIS_MCP_ALLOW_WRITE=1 \
  -- /absolute/path/to/.venv/bin/openbis-mcp-server

Confirm with mcp__openbis__get_server_info — the response includes "write_enabled": true. Until you do this, the read tools work but every write tool returns an error explaining how to enable it.

Register with Claude Desktop (macOS)

The Claude Desktop app launches the MCP server as a stdio subprocess. On macOS there is one non-obvious trap to avoid before configuring it; please read the next section first.

⚠️ Do not install under ~/Desktop, ~/Documents, or ~/Downloads

macOS protects those three folders with TCC (Transparency, Consent & Control). The Claude Desktop app is not granted access to them by default, and that denial is inherited by every MCP subprocess it spawns. The result is that Python can't even read its own pyvenv.cfg from a virtualenv placed there:

PermissionError: [Errno 1] Operation not permitted:
  '/Users/you/Desktop/.../.venv/pyvenv.cfg'
Fatal Python error: init_import_site: Failed to import the site module

The interpreter dies before any of this server's code runs, the stdio transport closes, and Claude Desktop reports "Server disconnected" with no useful UI-level error. Install the project somewhere else — for example ~/Codes/, ~/dev/, or ~/src/. The walkthrough below uses ~/Codes/.

(If you really need the project on Desktop you can grant access in System Settings → Privacy & Security → Files & Folders → Claude → Desktop Folder, then fully quit and relaunch Claude. The relocated install is the more robust fix because it survives macOS upgrades and TCC resets.)

Step-by-step setup on macOS

1. Clone and install into a non-protected directory:

   mkdir -p ~/Codes
   cd ~/Codes
   git clone https://github.com/biterik/openbis-mcp-server.git
   cd openbis-mcp-server
   python3 -m venv .venv
   .venv/bin/pip install --upgrade pip
   .venv/bin/pip install -e .
   

   This creates the console script at /Users/<you>/Codes/openbis-mcp-server/.venv/bin/openbis-mcp-server. Note the absolute path — you'll need it in the next step.

2. Create a personal access token in the openBIS web UI (User menu → Personal Access Tokens → Create). Save it to a single-line file, matching the pyBIS convention:

   mkdir -p ~/.pybis
   printf '%s' 'PASTE-YOUR-TOKEN-HERE' > ~/.pybis/openbis.imm.rwth-aachen.de.token
   chmod 600 ~/.pybis/openbis.imm.rwth-aachen.de.token
   

   Replace the host portion of the filename if your openBIS lives elsewhere.

3. Edit Claude Desktop's config at ~/Library/Application Support/Claude/claude_desktop_config.json. If the file already exists, merge the mcpServers entry into the existing JSON; otherwise create it with this content (substitute your real username for <you> and your openBIS host for the URL):

   {
     "mcpServers": {
       "openbis": {
         "command": "/Users/<you>/Codes/openbis-mcp-server/.venv/bin/openbis-mcp-server",
         "env": {
           "OPENBIS_URL": "https://openbis.imm.rwth-aachen.de",
           "OPENBIS_TOKEN_FILE": "/Users/<you>/.pybis/openbis.imm.rwth-aachen.de.token"
         }
       }
     }
   }
   

   Use absolute paths in command and OPENBIS_TOKEN_FILE. Tilde (~) expansion is not guaranteed in this context, and the MCP subprocess does not inherit your interactive shell's PATH.

   To enable the write tools (create_*, update_*, delete_entity), add "OPENBIS_MCP_ALLOW_WRITE": "1" to the env block. Leave it out for read-only.

4. Fully quit Claude Desktop with ⌘Q — closing the window is not enough; the menu-bar process and any running MCP subprocesses must exit so the new config is read on relaunch. Then reopen the app.

5. Verify by asking the agent to call get_server_info. It should return the openBIS URL, server version, and "write_enabled": true|false.

Troubleshooting on macOS

The Claude Desktop log for this server lives at ~/Library/Logs/Claude/mcp-server-openbis.log. Tail it while restarting the app:

tail -f ~/Library/Logs/Claude/mcp-server-openbis.log

Common failure modes:

• PermissionError: [Errno 1] Operation not permitted: '.../pyvenv.cfg' — the install path is under ~/Desktop, ~/Documents, or ~/Downloads and TCC is blocking access. Move the project (see the warning above); recreating the venv at the new location is required because shebangs and pyvenv.cfg hard-code absolute paths.
• Server transport closed unexpectedly with no other log lines — the command path in claude_desktop_config.json is wrong, or the venv was created elsewhere and copied in. Check head -1 /Users/<you>/Codes/openbis-mcp-server/.venv/bin/openbis-mcp-server; the shebang must point at the same .venv/bin/python3 that exists today.
• connection: ... in the get_server_info response — credentials or URL are wrong, or the openBIS server is unreachable. Test the token outside Claude with openbis-mcp-server from the venv and the same env vars.

Project structure

openbis-mcp-server/
  src/openbis_mcp_server/
    __init__.py
    __main__.py        # entry point — `python -m openbis_mcp_server`
    server.py          # FastMCP server, all tool definitions
    openbis_client.py  # pyBIS connection wrapper, lazy login
    s3_support.py      # S3 config, upload helpers, linked-dataset registration
  tests/
    test_smoke.py      # offline tests (no live openBIS needed)
  pyproject.toml
  README.md
  .env.example
  .gitignore

Roadmap

• Read-only browsing
• Schema introspection (sample/dataset/experiment types, vocabularies)
• Dataset file listing + single-file download
• Write operations behind explicit env-var gate
• S3-linked dataset support (upload to S3, register LINK-kind dataset, presigned URLs)
• Higher-level workflows (e.g. ingest_lammps_run(folder) combining schema lookup, file consolidation, and upload)
• Bulk operations (multi-sample / multi-dataset create in one call)
• Search predicates richer than equality (>=, contains, date ranges)

License

Currently unlicensed (all rights reserved by default). A permissive license will be added before any external contributions are accepted.