Surface and validate Claude's hidden assumptions about the project for user confirmation. Use when starting a new project, onboarding to a codebase, before major architectural decisions, or when the user says "hypotheses", "tu pars du principe que", "assumptions", "common ground". Invoke with /common-ground [--list] [--check] [--graph].
From atum-systemnpx claudepluginhub arnwaldn/atum-system --plugin atum-systemThis skill uses the workspace's default tool permissions.
references/assumption-classification.mdreferences/file-management.mdreferences/reasoning-graph.mdProvides UI/UX resources: 50+ styles, color palettes, font pairings, guidelines, charts for web/mobile across React, Next.js, Vue, Svelte, Tailwind, React Native, Flutter. Aids planning, building, reviewing interfaces.
Fetches up-to-date documentation from Context7 for libraries and frameworks like React, Next.js, Prisma. Use for setup questions, API references, and code examples.
Integrates PayPal payments with express checkout, subscriptions, refunds, and IPN. Includes JS SDK for frontend buttons and Python REST API for backend capture.
Surface Claude's implicit assumptions about the project so the user can validate or correct them before work begins.
Parse $ARGUMENTS:
| Flag | Mode | Description |
|---|---|---|
| (none) | Default | Surface & Adjust: two-phase interactive flow |
--list | List | Read-only view of all tracked assumptions |
--check | Check | Quick validation of current assumptions |
--graph | Graph | Generate Mermaid diagram of reasoning structure |
| Topic | Reference | Load When |
|---|---|---|
| Assumption Types & Tiers | references/assumption-classification.md | Classifying assumptions, determining type or tier |
| File Management | references/file-management.md | Storage operations, project ID, ground file format |
| Reasoning Graph | references/reasoning-graph.md | Using --graph flag, generating Mermaid diagrams |
git remote get-url origin 2>/dev/null
If found, use URL as project ID. Fallback: current working directory path. Sanitize to filesystem-safe string for storage path.
Read configuration files to infer assumptions:
package.json, tsconfig.json, .eslintrc*, .prettierrc (JS/TS)pyproject.toml, setup.py, ruff.toml (Python)Cargo.toml (Rust), go.mod (Go), pom.xml (Java)docker-compose.yml, .env.example, Dockerfile.github/workflows/, CI configsCLAUDE.md, .claude/ configPhase 1 — Surface & Select: Present assumptions grouped by category via AskUserQuestion (multiSelect):
For uncertain items, ask direct clarifying questions.
Phase 2 — Adjust Tiers: Present selected assumptions with proposed tiers via AskUserQuestion:
Write to ~/.claude/common-ground/{project_id}/COMMON-GROUND.md and ground.index.json.
See references/file-management.md for formats.
## Common Ground Complete
**Project:** {project_name}
**Tracked Assumptions:** {count}
- ESTABLISHED: {n} (high confidence)
- WORKING: {n} (medium confidence)
- OPEN: {n} (needs validation)
Load and display COMMON-GROUND.md grouped by tier. If no file exists, redirect to default mode.
Quick validation: present assumptions via AskUserQuestion with options "All valid", "Some need updates", "Full review needed". Update last_validated timestamp.
## Reasoning Graph