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MedHarness

Design-control checks for software teams — traceability, verification, SOUP and releases, as CI gates.

PyPI License: MIT Python 3.11+

MedHarness keeps a Design History File (DHF) as plain YAML in your repository and checks it with ordinary code: does every requirement trace to its parent, is each one verified the way it says, does the SOUP register match what ships. Each check is a command that answers in JSON with an exit code, so it drops into any CI. An optional AI workflow drafts the design and the code for a change request; the checks never ask a model.

Quick start

pip install medharness
mkdir my-device && cd my-device
medharness init            # writes DHF/ with sample items, and CLAUDE.md
medharness verify dhf      # does the design hold together?

Replace the sample items with your own, then add the checks to CI.

What it checks

Command The question it answers
verify dhf Does the V-model hold together — schema, required links, dangling links, cycles, coverage?
verify tests Is each requirement verified by the method it declares — a Test requirement by a passing test?
verify soup Is the SOUP register what actually ships, and is any of it known-vulnerable?
verify completion Is a change request's record complete, and is every item it changed verified?
workflow check-changes Did the branch change the items its change request said it would?
workflow check-approval Did a reviewer approve the exact commit being merged?
$ medharness verify dhf
FAIL [cycle] SRS-014 → SYS-006 → SRS-014
FAIL [required] SRS-022: SRS derives_from → SYS (count=0, need ≥1)
WARN [coverage] RISK→RCM: 3/4 covered

Broken structure — a cycle, a missing required link, a link to nothing — always fails. Design not yet written — an item with no child yet — only warns, unless you pass --fail-on-uncovered.

What a project looks like

my-device/
├── DHF/
│   ├── config/global.yaml       # the project name — and only what you change
│   └── items/                   # one YAML file per item, one directory per type
│       ├── 01_crs/CRS-001.yaml
│       ├── 03_srs/SRS-001.yaml
│       └── …                    # UC SYS SYSARCH MODULE SWDD RISK RCM SOUP CR DEF REL
└── CLAUDE.md                    # product context, read by the AI stages

The 13 item types, their lifecycles, which links are required, and the specification templates are defaults inside the package, so a project gets their improvements by upgrading medharness. To change one, override it:

To change Do this
A setting, e.g. which links are required Set its key in global.yaml — it replaces the default key
An item type's fields Put DHF/config/doc_types/<type>.yaml — it replaces the default type of that code
A new item type Add a file there with a new code
A type you don't use omit_doc_types: [UC] in global.yaml
A specification template Put a file of the same name in DHF/documents/specs/

The defaults are in dhfkit/templates/config and dhfkit/templates/specs.

An item is a small YAML file. Links are written on the child and point up:

id: SRS-012
title: Password must be at least 12 characters
derives_from: [SYS-004]
verification_method: [Test]
testing: |
  T1: an 11-character password is rejected

Fitting it into what you already have

  • Tests. Any runner that writes JUnit XML. Tag each test case with the requirement it verifies — the medharness.links property, or @links:SRS-012 in the test name. In pytest: @pytest.mark.dhf_links("SRS-012").

  • CI. Every check prints JSON to stdout and exits 0 pass, 1 fail. The smallest useful pipeline is two steps in a job that checks out the repository:

    - run: pip install medharness==0.40.0
    - run: medharness verify dhf --fail-on-uncovered
    

    The full recipe, including the release job, is in adopting.md.

  • Requirements kept elsewhere. MedHarness reads the item files under DHF/items/. To check requirements that live in another tool, export them into that format — one YAML file per item — and run the same commands. The format is specified in interface.md.

  • No AI. Nothing above needs a model. The AI workflow below is opt-in.

The AI change workflow (optional)

flowchart LR
    CR["CR opened"] --> PLAN["build plan<br/>AI drafts the design"]
    PLAN --> REV{"Human review"}
    REV -.->|rejected| PLAN
    REV -->|approved| CODE["build code<br/>AI writes code and tests"]
    CODE --> GATES["verify *<br/>ordinary code decides"]
    GATES -.->|fails| CODE
    GATES ==>|passes| MERGE["merge"]
    MERGE -.->|"tag v*"| REL["build release"]

build plan and build code run the claude CLI by default (npm install -g @anthropic-ai/claude-code), or any MEDHARNESS_{DESIGN,DESIGN_REVIEW,DEVELOP,CODE_REVIEW}_MODEL=provider:model (anthropic, openai, deepseek; MEDHARNESS_{STAGE}_BASE_URL for Azure, Ollama or vLLM). They run an agent with a shell, so run them on an ephemeral CI runner — read ai-security.md first.

Commands

Two CLIs from one package: medharness runs the checks and the workflow; dhfkit stores and reads the items. Both take --dhf PATH before the command, defaulting to DHF. Every command writes JSON to stdout and readable lines to stderr; --help on any of them lists its options.

verify — reads the DHF only

Command Returns
medharness verify dhf gate result¹
medharness verify tests --junit test-results gate result
medharness verify soup gate result
medharness verify completion --cr CR-034 gate result

workflow — needs Git or GitHub; CI helpers

Command What it does Returns
medharness workflow check-changes --cr CR-034 Compares the branch diff with the CR's affected_items gate result
medharness workflow check-approval --pr 42 Requires an approving review of the PR's head commit; needs GH_TOKEN gate result

¹ Every gate answers {gate, passed, summary, errors, warnings}; see interface.md.

build — writes items, code or artifacts

Command What it does Returns
medharness build plan --cr CR-034 AI drafts the CR's design items and impact analysis outcome, items_changed, review_cycles
medharness build code --cr CR-034 AI writes the code and tests for the approved design outcome, files_changed, review_cycles
medharness build soup --write Reconciles SOUP items with your dependency manifests; without --write, only reports to_create, to_update, orphans
medharness build release --version 1.0.0 --out-dir release --write Checks the DHF, CRs and open defects, writes the baseline, BOM, SBOM and evidence, and — only if every check passed — records the REL item outcome, cr_ids, rel_uid, artifacts, errors

Setup

Command What it does Returns
medharness init Scaffolds DHF/ and CLAUDE.md in the current directory; refuses if DHF/ exists project_name, created
medharness doctor Checks Python, the CLIs, gh auth, and the DHF checks, healthy

dhfkit — the items

Command What it does Returns
dhfkit item list --type SYS Lists items of a type one JSON object per line
dhfkit item get SRS-012 One item, with its links resolved the item
dhfkit item create --type SRS --data '{...}' Adds an item; its ID is allocated the item
dhfkit item update SRS-012 --data '{...}' Merges fields into an item the item
dhfkit item transition CR-034 completed Moves an item through its lifecycle; without a state, lists where it can go the item
dhfkit validate Checks every item against its type's schema, and that no two files claim one ID valid, errors, item_count
dhfkit doc SRS --format html Renders a specification from the items — md by default, html or pdf (needs medharness[docs]); ALL for every type md_path, plus html_path or pdf_path
dhfkit sbom CycloneDX 1.6 SBOM from the SOUP register path, components

Example project

ContourLab is an example project used to exercise MedHarness end to end: its DHF, its CI, and changes made through the AI workflow.

Documentation

adopting.md starting fresh, the CI recipe, bringing an existing DHF, releases
interface.md the gate result, exit codes, what may change
ai-security.md what the AI stages can do, and running without them
architecture.md how the code is organised
CHANGELOG.md version history

License

MIT. See LICENSE.

Metadata

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