An MCP server front-end for pycti.

Inspired by Spathodea-Network/opencti-mcp, but rather than trying to reflect OpenCTI content back to the caller, the aim here is to condense, normalize, and consolidate data from OpenCTI into JSON for the LLM to consume in order to acheive the following improvements:

• More verbosity in field naming so the LLM can better intuit what a field represents
• Resolve parts of GraphQL-linked entities into the response so more context is available in a single MCP response
• Reduce the inclusion of non-informative metadata to reduce context window usage

To use:

1. Copy pycti_tools/local_settings.py.sample to pycti_tools/local_settings.py, and edit the new file to your needs
2. Run uv run mcp_server_octi.py

Usage details:

usage: mcp_server_octi.py [-h] [-p PORT] [-s]

Execute the OpenCTI MCP Server

options:
  -h, --help       show this help message and exit
  -p, --port PORT  TCP port to listen on (default 8002 - ignored if -s)
  -s, --stdio      Start an STDIO server (default: off)

Adding New Tools

New tools may be added by creating a new Python module under pycti_tools/, then adding it to the the __all__ list in pycti_tools/__init__.py. The only requirement is that your code must implement exactly one tool per module, and the module must contain a class ToolSpec that describes the tool using the following three class variables:

• name: The name of the tool as it will be exposed by the MCP server
• description: A description of the tool to provide via the MCP server as will
• fn: The function that will act as the entrypoint for the tool

Example from lookup_reports.py below:

class ToolSpec:
    name = "opencti_reports_lookup"
    description = """Search in OpenCTI for any reports matching the search term `search`, and having creation timestamps between
                     `earliest` and `latest`. Any of these input variables can be omitted by setting them to None, if the aren't
                     desired for filtering reports. The result will be a list of structured objects representing all the reports
                     matching the provided criteria.
                  """
    fn = opencti_reports_lookup

Implemented Tools

OpenCTI Observable Lookup

Name: opencti_observable_lookup

Inputs: observable (str): An Observable

This tool will perform an exact-match lookup in OpenCTI for the observable value provided as observable.

Given an observable, queries for it in OpenCTI and, if it exists, returns JSON object representing the findings from OpenCTI for the observable, with the following fields:

• observable_value: The observable value, as it is recorded in OpenCTI
• stix_id: The STIX Id of the observable object
• opencti_id: The entity Id of the observable object in OpenCTI
• data_type: The STIX Observable type
• descriotion: A short description of the observable, from OpenCTI
• created: Creation data within OpenCTI
• last_updated: The last time an update was written to the observable object in OpenCTI
• labels: A list of labels (as strings) attached to the observable
• external_reports: A list of external reports containing the observable
  • name: The title of the report
  • urls: List of URLs to fetch the report (or parts of it)
• notes: Notes in OpenCTI written about the observable
• opinions: Opinions in OpenCTI about the observable
  • sentiment: The sentiment expressed in the opinion.
  • explanation: An explanation of the opinion.

OpenCTI Adversary Lookup

Name: opencti_adversary_lookup

Inputs: name (str): A name or alias of an adversary, intrusion set, threat actor, threat group, or campaign

This tool will search across all "adversary" type entities: Intrusion Sets, Actors, and Campaigns for the adversary matching name either in its formal name or one of its aliases.

• stix_id: The STIX ID of the adversary object.
• opencti_id: The entity ID of the adversary object in OpenCTI.
• name: The name of the adversary.
• data_type: The type of the entity (e.g., "Threat Actor").
• description: A brief description of the adversary.
• created: The creation date of the adversary in OpenCTI.
• last_updated: The last time the adversary was updated in OpenCTI.
• labels: A list of labels (as strings) attached to the adversary.
• first_seen: The first date the adversary was observed.
• last_seen: The last date the adversary was observed.
• external_reports: A list of external reports related to the adversary, each containing:
  • name: The title of the report.
  • urls: List of URLs to access the report or its parts.
• notes: A collection of notes associated with the adversary.
• opinions: A list of opinions about the adversary, where each opinion includes:
  • sentiment: The sentiment expressed in the opinion.
  • explanation: An explanation of the opinion.

OpenCTI Report Lookup

Name: opencti_report_lookup

Inputs:

• search (str): An optional search term to use to filter to reports matching a string term
• earliest (str): Optional timestamp that sets the earliest date to search for reports
• latest (str): Optional timestamp that sets the latest date to search for reports

This tool will perform a lookup in OpenCTI of all of the threat reports matching a search term provided as search, between the creation timestamps earliest and latest. Any of the inputs can be omitted (specified as None).

• stix_id: The STIX ID of the report.
• opencti_id: The entity ID of the report in OpenCTI.
• name: The name of the report.
• data_type: The type of the entity (e.g., "Report").
• description: A brief description of the contents of the report.
• created: The creation date of the report.
• modified: The most recent modification date of the report.
• published: The report's publication date.
• labels: A list of labels (as strings) attached to the report.
• external_urls: A list of external URLs referencing sourcing of the report.
• report_types: The type label(s) of the analysis report.
• objects: The STIX objects (Entities and Cyber observables) contained within the report.