/start

name: start
description: One command from "plugin installed" to "running brief on your idea." Combines /mycelium:setup (project-state initialization) and /mycelium:interview (10-minute discovery brief) into a single flow. Run this immediately after installing the Mycelium plugin — it's the recommended entry point for first-time users.
metadata:
  framework_dependency: "mycelium"
  framework_dependency_note: "This skill is designed to run within the Mycelium framework (https://github.com/haabe/mycelium). Standalone use will skip the canvas state, theory gates, and harness behavior the skill assumes. Install: /plugin install mycelium@haabe-mycelium."

/mycelium:start — combined first-time entry

When this skill runs, follow the flow below. The skill is designed so a first-time user goes from "plugin installed" to "holding a one-page brief on their idea" in a single invocation.

Step 1: Welcome (~30 seconds of context, then move on)

Output a short welcome before doing anything. Do NOT skip this — the install-to-here gap is the friction point this skill exists to address. The user just installed a 45-skill framework and has no context yet.

> "Welcome to Mycelium. > > Mycelium makes the agent think before it builds — it can't skip the hard questions; each step has to clear an evidence check first. Grounded in 30+ established product-thinking frameworks; you'll meet the relevant ones as they come up. > > Two quick steps: > 1. Set up Mycelium's files in `.claude/` — about 10 seconds. Your existing files (CLAUDE.md, README, etc.) aren't touched; only a new `.claude/` directory is added. > 2. A 10-minute discovery brief: 4 questions about your idea, then a one-page brief covering who it's for, the biggest assumption, the biggest risk, and your next concrete move. > > Let's begin."

Step 2: Detect existing state — HARD GATE

**This must be the very first action after the welcome. Do NOT run any other Bash commands, Edit/Write operations, or "let me prepare the directories" reasoning before this gate fires.**

Run exactly this check, and only this check:

test -f "$CLAUDE_PROJECT_DIR/.claude/diamonds/active.yml"

• **If exit code 0** (file EXISTS): the project already has Mycelium state. Skip directly to Step 4 routing output. **Do NOT run setup. Do NOT run mkdir. Do NOT touch `.gitkeep` stubs.** Setup-style operations on an already-initialized project waste tokens and trigger Read-before-Write tool errors when the agent then tries to write to existing files. Detected during 2026-05-09 plugin-form dogfood — the agent ran `mkdir -p .claude/...` before honoring this gate, then hit a Write error on `active.yml` and only then realized the project was initialized. The fix is structural: the gate is the first action.

• **If exit code 1** (file does NOT exist): invoke the setup workflow inline. Follow the instructions in `${CLAUDE_PLUGIN_ROOT}/skills/setup/SKILL.md` exactly — same Step 1 detection (which will fall through), Step 2 directory creation with `.gitkeep` stubs, Step 3 starter file writes, Step 5 confirmation message — **but DEFER setup's Step 4 (the AGENTS.md prompt) to after the brief** (see below). Do not duplicate the setup logic here; reference it.

**AGENTS.md deferral (v0.56.0)**: in the /start composition, setup's Step 4 question does NOT fire before the interview. A first-time user's opening minutes must go to their idea, not to file administration — the 2026-07-02 roadmap dogfood run showed the AGENTS.md exchange consuming the first two conversational rounds before Question 1 was asked. Instead: after the brief is rendered and the depth menu is answered, IF `<project_root>/AGENTS.md` is absent or lacks a Mycelium section, ask setup's Step 4 question then (one exchange, at the natural pause). Setup's detect-first rule still applies: an AGENTS.md that already covers Mycelium is skipped silently. When `/mycelium:setup` is run standalone (not via /start), its Step 4 order is unchanged.

After setup completes, do NOT print setup's "Next:" line — this skill is the next step. Print:

> "Setup done. Now: 4 questions about your idea, ~10 minutes."

Step 3: Run interview (universal-flow shape)

Invoke the interview workflow inline. Follow the instructions in `${CLAUDE_PLUGIN_ROOT}/skills/interview/SKILL.md` from Phase 0 onward.

Because setup just ran, the canvas is empty — /interview's canvas-state detection will route to the Universal Brief Flow (the 4-question brief shape, not the legacy time-budget-routed ceremony). Render the brief, write canvas state, render the depth menu. Per opp-006 narration discipline in interview/SKILL.md, do not narrate phase numbers to the user — reference the outcome (e.g., "the brief", "the project-type question") instead of the phase index.

After the brief is rendered and the user picks a depth-menu option, the start skill is done. Hand off to whatever the user chose (`/mycelium:assumption-test` for "Test the biggest assumption", continued discovery for "Go deeper", graceful exit for "Stop for now", etc.).

Step 3b: Derive purpose properties (immediately after why/how/what land)

**The why/how/what are not decoration — everything below is checked against them, so they have to be checkable.** Propose a property list from what the user just wrote, then have them confirm it. Write to `purpose.yml#purpose_properties`. Full contract: `docs/purpose-stance.md`.

**For each element, ask yourself: can I name a specific solution that would CONTRADICT this?**

• Yes → it is a candidate property. Record `verbatim`, `source` (why/how/what), and the contradicting

solution in `contradicted_by`.

• No → **do not force one.** Quality adjectives ("secure", "accessible", "fast", "simple") yield

nothing checkable, because every candidate solution claims to satisfy them. Measured 2026-08-23: "accessible and secure" produced no checkable property at all.

**When a word fails, ask the user — and offer candidates rather than an open questio