id: README kind: overview status: draft version: 1.0.0

EngiMCP

EngiMCP is a local MCP server for managing engineering projects stored as Markdown, YAML frontmatter, and Git history. It gives an LLM agent structured, safe access to requirements, engineering decisions, calculations, tests, tasks, BOM items, document relationships, impact analysis, context packs, and ordinary project files.

The source of truth stays in the project folder. The SQLite index under .engimcp/index.sqlite is derived data and can be rebuilt.

Related MCP server: mcp-docs

Why It Exists

Long-running engineering work cannot live only in chat. Requirements drift, decisions get forgotten, tests stop matching design assumptions, and documents become inconsistent.

Codex is strong at inspecting and changing code repositories, but engineering documentation needs a domain layer on top of files. EngiMCP exposes IDs, document kinds, frontmatter, links, graph relationships, validation, impact analysis, and focused writes so the agent can answer questions such as:

What breaks if we change the battery?
Prepare context for changing the project motors.
Create an EDR for this design choice.
Find requirements that are not verified by tests.

Requirements

• Node.js 20 or newer.

• npm.

• Git, for Git status/snapshot/commit workflows.

• An MCP-compatible client such as Codex, Claude Code, or another local MCP client.

User Guide

EngiMCP is meant to be used through an MCP client. In normal use, you do not call TypeScript code directly. You start the server, connect it to your agent, and then ask the agent engineering-project questions in plain language.

1. Prepare an Engineering Project Folder

Choose or create a local folder for the project:

mkdir -p ~/Work/Projects/RC-Car
cd ~/Work/Projects/RC-Car
git init

EngiMCP will keep the source of truth in this folder as Markdown files plus project.yaml.

2. Install and Build EngiMCP

From the EngiMCP repository:

npm install
npm run build

3. Connect It to an MCP Client

Use the built server command in your MCP client configuration:

node /absolute/path/to/EngiMCP/dist/index.js --root /absolute/path/to/your/project

For a read-only review session:

node /absolute/path/to/EngiMCP/dist/index.js --root /absolute/path/to/your/project --read-only

After package installation, the binary form is:

engimcp --root /absolute/path/to/project
engimcp --root /absolute/path/to/project --read-only

When --root is set, tool calls must use that same project root. When --read-only is set, write-like tools are rejected.

4. Initialize the Project

Ask your agent:

Initialize this folder as an EngiMCP project.

The agent should call:

engi_project_init(root="/absolute/path/to/project")

This creates the basic project files:

project.yaml
docs/
templates/
.engimcp/

5. Start Working

Useful first prompts:

Show project status.
Create a requirement: the car must run for 30 minutes.
Create an engineering decision for using four geared motors.
What breaks if we change the battery?
Prepare context for changing the project motors.
Find requirements that are not verified by tests.
Validate the project and show what needs fixing.
Show the Git diff summary.

The agent will use EngiMCP tools to read the right documents, build context, analyze links, and apply focused edits.

Common User Workflows

Create Requirements

Ask:

Add a requirement that the radio-controlled car must stop safely when radio control is lost.

EngiMCP creates a managed Markdown requirement with an ID such as FR-001, NFR-001, SEC-001, or AC-001.

Record Engineering Decisions

Ask:

Create an EDR explaining why we selected a 2S LiPo battery.

EngiMCP creates an Engineering Decision Record such as EDR-0001 with context, options, decision, consequences, and links.

Analyze Change Impact

Ask:

What documents, tests, BOM items, and decisions are affected if we change the battery?

EngiMCP follows frontmatter links and inline links to return direct and transitive impact.

Prepare Focused Context

Ask:

Prepare context for changing the drive motors.

EngiMCP builds a compact context pack instead of forcing the agent to read the whole project.

Edit Documents Safely

Ask:

Update the Battery Estimate section with the new runtime calculation.

The agent should use section-level document tools, so the edit stays focused and reviewable in Git.

Work with Ordinary Files

Ask:

List files under docs.
Read docs/battery-notes.md.
Create a folder for test reports.
Move this draft file into docs/archive.
Delete this temporary note.

EngiMCP uses the safe engi_fs_* layer. Deletes go to .engimcp/trash/... by default.

Project Format

A valid project has:

project.yaml
docs/
templates/
.engimcp/

Managed Markdown documents use YAML frontmatter with at least:

---
id: DOC-EXAMPLE
kind: design_doc
status: draft
version: 0.1.0
---

You can edit Markdown files manually in VS Code, Obsidian, or another editor. Run validation after manual edits:

Validate the project.

Quick Start

1. Start the MCP server from this repository or install it as a binary.

2. Connect an MCP client over stdio.

3. Initialize or open a project root.

4. Call engi_project_status to verify the project.

5. Use engi_context_pack before asking the agent to change a subsystem.

6. Use engi_impact_analyze before changing requirements, decisions, battery, motors, BOM, tests, or calculations.

7. Use engi_validate_project after changes.

8. Review the Git diff with engi_git_status.

Example workflow:

engi_project_status(root)
engi_context_pack(root, task="we are changing the project motors")
engi_impact_analyze(root, changed_ids=["DOC-RC-CAR-BATTERY"])
engi_doc_patch_section(root, id="DOC-RC-CAR-BATTERY", heading_path=["Initial Estimate"], ...)
engi_validate_project(root)
engi_git_status(root)

Core Tools

Project:

• engi_project_init

• engi_project_status

• engi_project_map

• engi_rebuild_index

Managed engineering documents:

• engi_doc_read

• engi_doc_create

• engi_frontmatter_patch

• engi_doc_patch_section

• engi_doc_add_relationship

Engineering entities:

• engi_requirement_create

• engi_decision_create

• engi_task_create

• engi_test_report_create

• engi_bom_item_create

Analysis and retrieval:

• engi_search

• engi_graph_query

• engi_impact_analyze

• engi_context_pack

• engi_validate_project

Git:

• engi_git_status

• engi_project_snapshot

• engi_git_commit

Safe filesystem layer:

• engi_fs_tree

• engi_fs_list

• engi_fs_read

• engi_fs_write

• engi_fs_mkdir

• engi_fs_move

• engi_fs_copy

• engi_fs_delete

• engi_fs_exists

• engi_fs_stat

• engi_fs_glob

Use engi_doc_* for managed engineering documents where IDs, frontmatter, links, graph, and validation matter. Use engi_fs_* for ordinary files and folders inside the project root.

Safety Model

EngiMCP is not raw filesystem access.

• All operations are restricted to project_root.

• Runtime --root pins the allowed project root.

• ../ traversal and absolute-path escape are rejected.

• Symlink escape outside the root is rejected.

• Deny patterns block .git, .env, SSH keys, secrets, private files, cache paths, and dependency folders.

• Project-configured deny patterns extend the defaults.

• Write-like tools respect read-only mode.

• Deletes use trash by default: .engimcp/trash/YYYY-MM-DD/<original-path>.

• Writes are atomic where practical.

• Write/move/copy/delete/mkdir operations write audit log entries.

• Overwrite-like operations refuse to modify files containing Git conflict markers.

Validation and Indexing

engi_validate_project checks IDs, required frontmatter, duplicate IDs, broken links, dependency cycles, and requirement verification gaps.

engi_rebuild_index regenerates .engimcp/index.sqlite from Markdown and frontmatter. Filesystem write-like operations rebuild the index after successful changes, and engi_project_status restores the index if it is missing.

Development Commands

npm run build
npm run lint
npm run format
npm run format:check
npm test
npm run check
npm run smoke

npm run check runs build, lint, format check, and the test suite. npm run smoke builds the project and runs a project-status smoke check against the radio-controlled car example.

Important Documentation

• docs/02_requirements/technical_requirements.md - functional and non-functional requirements.

• docs/02_requirements/filesystem_overlay_requirements.md - safe filesystem layer requirements.

• docs/02_requirements/acceptance_criteria.md - acceptance criteria.

• docs/03_architecture/system_architecture.md - system architecture.

• docs/04_data_model/entities_and_schema.md - entity and frontmatter model.

• docs/05_mcp_interface/tools_spec.md - MCP tool contracts.

• docs/05_mcp_interface/filesystem_tools_spec.md - filesystem tool contracts.

• docs/07_quality/testing_strategy.md - test strategy.

• docs/08_security/security_model.md - security model.

• docs/09_delivery/roadmap.md - milestone roadmap.

• CHANGELOG.md - release notes.

License

MIT.