Usage Pulse P0 shipped: a zero-storage, cross-startup 'pulse' that reads its numbers at view-open

What shipped

The full P0 of Usage Pulse — a cross-startup dashboard in the 📈 Pulse tab — went from locked spec to installed app. Six glanceable views, each with a plain-language caption beside it (so a non-engineer never wonders what a number means):

• Effort split — output tokens per startup this week (bars)
• Momentum — a 14-day active-day dot strip + days-since-active
• Fan-out — internal agent steps per question, vs that startup's own baseline
• Explore vs produce — read/search vs edit/run tool mix
• Friction — times AI waited on you + tool errors (with an honest "history starts" note)
• Shipped vs thrash — asks that day vs commits that landed

The engine: one pure function, zero storage

pulse.rs::usage_pulse() rolls every number at view-open from data already on disk and writes nothing: the hook stream (session-events.jsonl), each DalkkakAI-run session's native transcript, and the GraphStore change nodes. Honest units only — output tokens, active days, counts. No total/cache tokens in any view (they're re-reads, noise), and no $ (a Max subscription has no per-token bill, so a dollar would be fabricated). Startup attribution is by cwd → granted root, longest-prefix-wins, ambiguity → a visible unassigned row — never confidently-wrong.

Verify the artifact, not the code that reads it

The design synthesis — which had impressively read the actual codebase — still got one thing wrong: it said the hook line had no cwd and no timestamp, and built the whole cold-start story around that gap. That claim came from sessionStatus.ts, which only parses {pane,event,tool,tpath}. But tail-ing the real session-events.jsonl showed every line is {pane,event,tool,cwd,tpath,ts} — the renderer just ignored two fields the hook was already writing. The cheaper, more-reliable attribution key was sitting unused.

Lesson, logged: a parser reading a subset of a file's fields is not evidence of the file's shape. Read the real artifact before designing around "field X doesn't exist."

Verified on real data

Before wiring the frontend, a throwaway Rust test ran the roller against the real hook log + transcripts: attribution matched (startup-ddalkkak vs home-dir → unassigned), the GraphStore commit join worked (25 and 1 commits on two real startups), local-tz day bucketing was correct, and blocks (26) / turns (31) / tool-mix all populated. Then the test was removed.

cargo check + tsc clean, bundled, installed. Full en/ko i18n. Spec/ADR-005 marked Built. Commit e34790b.