|
| 1 | +# Smriti Demo: From Deep Dive to Team Knowledge |
| 2 | + |
| 3 | +## The Problem |
| 4 | + |
| 5 | +Priya is a senior engineer at a startup. She just spent 2 hours in a Claude |
| 6 | +Code session doing a deep review of their payment service — a critical codebase |
| 7 | +she inherited when the original author left. |
| 8 | + |
| 9 | +During the session, she and Claude: |
| 10 | + |
| 11 | +- Traced a race condition in the webhook handler that causes duplicate charges |
| 12 | +- Discovered the retry logic uses `setTimeout` instead of exponential backoff |
| 13 | +- Decided to replace the hand-rolled queue with BullMQ |
| 14 | +- Found that the Stripe SDK is 3 major versions behind and the API they use is deprecated |
| 15 | +- Mapped out the full payment flow across 14 files |
| 16 | +- Identified 3 missing error boundaries that silently swallow failures |
| 17 | + |
| 18 | +That's a **goldmine** of institutional knowledge. But the Claude session is |
| 19 | +just a 400-message transcript buried in `~/.claude/projects/`. Tomorrow, when |
| 20 | +her teammate Arjun picks up the webhook fix, he'll start from scratch. When the |
| 21 | +intern asks "why BullMQ?", nobody will remember the tradeoff analysis. |
| 22 | + |
| 23 | +**This is the problem Smriti solves.** |
| 24 | + |
| 25 | +--- |
| 26 | + |
| 27 | +## Act 1: The Session Ends |
| 28 | + |
| 29 | +Priya's Claude Code session just finished. Here's what her terminal looks like: |
| 30 | + |
| 31 | +``` |
| 32 | +$ # Session over. 2 hours of deep review — bugs, decisions, architecture notes. |
| 33 | +$ # All sitting in a Claude transcript she'll never look at again. |
| 34 | +``` |
| 35 | + |
| 36 | +She has two paths to preserve this knowledge: |
| 37 | + |
| 38 | +| Path | Command | What it does | |
| 39 | +|------|---------|--------------| |
| 40 | +| **Ingest** | `smriti ingest claude` | Import into searchable memory (personal) | |
| 41 | +| **Share** | `smriti share --segmented` | Export as team documentation (git-committed) | |
| 42 | + |
| 43 | +She'll do both. |
| 44 | + |
| 45 | +--- |
| 46 | + |
| 47 | +## Act 2: Ingest — Building Personal Memory |
| 48 | + |
| 49 | +``` |
| 50 | +$ smriti ingest claude --project payments |
| 51 | +``` |
| 52 | + |
| 53 | +``` |
| 54 | + Discovering sessions... |
| 55 | + Found 1 new session in payments |
| 56 | +
|
| 57 | +Agent: claude-code |
| 58 | +Sessions found: 1 |
| 59 | +Sessions ingested: 1 |
| 60 | +Messages ingested: 412 |
| 61 | +Skipped: 0 |
| 62 | +``` |
| 63 | + |
| 64 | +That's it. 412 messages are now indexed — full-text searchable with BM25, |
| 65 | +ready for vector embedding, tagged with project and agent metadata. |
| 66 | + |
| 67 | +**What just happened under the hood:** |
| 68 | + |
| 69 | +1. Smriti found the JSONL transcript in `~/.claude/projects/-Users-priya-src-payments/` |
| 70 | +2. Parsed every message, tool call, file edit, and error |
| 71 | +3. Stored messages in QMD's content-addressable store (SHA256 dedup) |
| 72 | +4. Registered the session with project = `payments`, agent = `claude-code` |
| 73 | +5. Auto-indexed into FTS5 for instant search |
| 74 | + |
| 75 | +Now Priya can search her memory: |
| 76 | + |
| 77 | +``` |
| 78 | +$ smriti search "race condition webhook" --project payments |
| 79 | +``` |
| 80 | + |
| 81 | +``` |
| 82 | +[0.891] Payment Service Deep Review |
| 83 | + assistant: The race condition occurs in src/webhooks/stripe.ts at line 47. |
| 84 | + The handler processes the event, then checks idempotency — but between |
| 85 | + those two operations, a duplicate webhook can slip through... |
| 86 | +
|
| 87 | +[0.823] Payment Service Deep Review |
| 88 | + user: What's the fix? Can we just add a mutex? |
| 89 | +
|
| 90 | +[0.756] Payment Service Deep Review |
| 91 | + assistant: A mutex won't work in a multi-instance deployment. The proper |
| 92 | + fix is to check idempotency BEFORE processing, using a database-level |
| 93 | + unique constraint on the event ID... |
| 94 | +``` |
| 95 | + |
| 96 | +Three weeks later, she barely remembers the session. But she can recall it: |
| 97 | + |
| 98 | +``` |
| 99 | +$ smriti recall "why did we decide on BullMQ for payments" --synthesize |
| 100 | +``` |
| 101 | + |
| 102 | +``` |
| 103 | +[0.834] Payment Service Deep Review |
| 104 | + assistant: After comparing the options, BullMQ is the clear winner... |
| 105 | +
|
| 106 | +--- Synthesis --- |
| 107 | +
|
| 108 | +The decision to adopt BullMQ for the payment queue was made during a deep |
| 109 | +review of the payment service. The existing implementation used a hand-rolled |
| 110 | +queue with setTimeout-based retries, which had several issues: |
| 111 | +
|
| 112 | +1. No exponential backoff — failed jobs retry immediately, hammering Stripe |
| 113 | +2. No dead-letter queue — permanently failed jobs disappear silently |
| 114 | +3. No persistence — server restart loses the entire queue |
| 115 | +4. No visibility — no way to inspect pending/failed jobs |
| 116 | +
|
| 117 | +BullMQ was chosen over alternatives: |
| 118 | +- **pg-boss**: Good, but adds Postgres load to an already-strained DB |
| 119 | +- **Custom Redis queue**: Reinventing the wheel; BullMQ is battle-tested |
| 120 | +- **SQS/Cloud queue**: Adds AWS dependency the team wants to avoid |
| 121 | +
|
| 122 | +BullMQ provides exponential backoff, dead-letter queues, Redis persistence, |
| 123 | +and a dashboard (Bull Board) — solving all four issues. |
| 124 | +``` |
| 125 | + |
| 126 | +That synthesis didn't come from a new LLM call about BullMQ. It came from |
| 127 | +**Priya's actual reasoning during the review**, reconstructed from her |
| 128 | +session memory. |
| 129 | + |
| 130 | +--- |
| 131 | + |
| 132 | +## Act 3: Share — Exporting Team Knowledge |
| 133 | + |
| 134 | +Ingesting is personal. Sharing is for the team. |
| 135 | + |
| 136 | +``` |
| 137 | +$ smriti share --project payments --segmented |
| 138 | +``` |
| 139 | + |
| 140 | +``` |
| 141 | + Segmenting session: Payment Service Deep Review... |
| 142 | + Found 5 knowledge units (3 above relevance threshold) |
| 143 | + Generating documentation... |
| 144 | +
|
| 145 | +Output: /Users/priya/src/payments/.smriti |
| 146 | +Files created: 3 |
| 147 | +Files skipped: 0 |
| 148 | +``` |
| 149 | + |
| 150 | +Smriti's 3-stage pipeline just: |
| 151 | + |
| 152 | +**Stage 1 — Segment**: Analyzed the 412-message session and identified 5 |
| 153 | +distinct knowledge units: |
| 154 | + |
| 155 | +| Unit | Category | Relevance | Action | |
| 156 | +|------|----------|-----------|--------| |
| 157 | +| Webhook race condition | bug/investigation | 9 | Shared | |
| 158 | +| BullMQ decision | architecture/decision | 8 | Shared | |
| 159 | +| Stripe SDK deprecation | project/dependency | 7 | Shared | |
| 160 | +| General code navigation | uncategorized | 3 | Filtered out | |
| 161 | +| Test setup discussion | uncategorized | 2 | Filtered out | |
| 162 | + |
| 163 | +**Stage 2 — Document**: Generated structured markdown using category-specific |
| 164 | +templates. A bug gets Symptoms → Root Cause → Fix → Prevention. A decision |
| 165 | +gets Context → Options → Decision → Consequences. |
| 166 | + |
| 167 | +**Stage 3 — Persist**: Wrote files, deduplicated via content hash, updated the |
| 168 | +manifest. |
| 169 | + |
| 170 | +Here's what landed on disk: |
| 171 | + |
| 172 | +``` |
| 173 | +payments/ |
| 174 | +└── .smriti/ |
| 175 | + ├── CLAUDE.md # Auto-discovered by Claude Code |
| 176 | + ├── index.json |
| 177 | + ├── config.json |
| 178 | + └── knowledge/ |
| 179 | + ├── bug-investigation/ |
| 180 | + │ └── 2026-02-28_webhook-race-condition-duplicate-charges.md |
| 181 | + ├── architecture-decision/ |
| 182 | + │ └── 2026-02-28_bullmq-for-payment-queue.md |
| 183 | + └── project-dependency/ |
| 184 | + └── 2026-02-28_stripe-sdk-v3-deprecation.md |
| 185 | +``` |
| 186 | + |
| 187 | +Let's look at the bug document: |
| 188 | + |
| 189 | +```markdown |
| 190 | +--- |
| 191 | +id: unit-a1b2c3 |
| 192 | +session_id: 6de3c493-60fa |
| 193 | +category: bug/investigation |
| 194 | +pipeline: segmented |
| 195 | +relevance_score: 9 |
| 196 | +entities: ["Stripe webhooks", "idempotency", "race condition", "PostgreSQL"] |
| 197 | +files: ["src/webhooks/stripe.ts", "src/db/events.ts"] |
| 198 | +project: payments |
| 199 | +author: priya |
| 200 | +shared_at: 2026-02-28T17:45:00Z |
| 201 | +--- |
| 202 | + |
| 203 | +# Webhook Race Condition Causing Duplicate Charges |
| 204 | + |
| 205 | +## Symptoms |
| 206 | + |
| 207 | +Customers occasionally receive duplicate charges for a single purchase. |
| 208 | +The issue occurs under high webhook volume — Stripe sends the same event |
| 209 | +twice within milliseconds, and both get processed. |
| 210 | + |
| 211 | +## Root Cause |
| 212 | + |
| 213 | +In `src/webhooks/stripe.ts`, the handler processes the event first, then |
| 214 | +checks the idempotency table. Between processing and the idempotency check, |
| 215 | +a duplicate webhook slips through. |
| 216 | + |
| 217 | +The vulnerable window is ~15ms (database round-trip time), which is enough |
| 218 | +for Stripe's retry mechanism to deliver a duplicate. |
| 219 | + |
| 220 | +## Investigation |
| 221 | + |
| 222 | +Traced the flow: `handleWebhook()` → `processEvent()` → `markProcessed()`. |
| 223 | +The idempotency check happens inside `markProcessed()`, AFTER the charge |
| 224 | +is executed. Should be BEFORE. |
| 225 | + |
| 226 | +## Fix |
| 227 | + |
| 228 | +Move the idempotency check to the entry point of `handleWebhook()`: |
| 229 | + |
| 230 | +1. Add a `UNIQUE` constraint on `webhook_events.stripe_event_id` |
| 231 | +2. `INSERT OR IGNORE` before processing — if the insert fails, the event |
| 232 | + was already handled |
| 233 | +3. Wrap the entire handler in a database transaction |
| 234 | + |
| 235 | +## Prevention |
| 236 | + |
| 237 | +- Add integration test that fires duplicate webhooks concurrently |
| 238 | +- Add monitoring alert on duplicate event IDs in the events table |
| 239 | +- Consider adding Stripe's recommended `idempotency-key` header to all |
| 240 | + API calls |
| 241 | +``` |
| 242 | + |
| 243 | +That's not a raw transcript. It's a **structured incident document** that any |
| 244 | +engineer can read, understand, and act on — without ever having been in the |
| 245 | +original session. |
| 246 | + |
| 247 | +--- |
| 248 | + |
| 249 | +## Act 4: The Payoff |
| 250 | + |
| 251 | +### Monday morning — Arjun picks up the webhook fix |
| 252 | + |
| 253 | +He opens the payments repo. Claude Code automatically reads |
| 254 | +`.smriti/CLAUDE.md` and sees the shared knowledge index. |
| 255 | + |
| 256 | +``` |
| 257 | +$ smriti search "webhook duplicate" --project payments |
| 258 | +``` |
| 259 | + |
| 260 | +He finds the full investigation, root cause, and fix — before writing a |
| 261 | +single line of code. |
| 262 | + |
| 263 | +### Two weeks later — the intern asks "why BullMQ?" |
| 264 | + |
| 265 | +``` |
| 266 | +$ smriti recall "why BullMQ instead of pg-boss" --synthesize --project payments |
| 267 | +``` |
| 268 | + |
| 269 | +The original tradeoff analysis surfaces instantly, with Priya's reasoning |
| 270 | +preserved verbatim. |
| 271 | + |
| 272 | +### A month later — Priya reviews a different service |
| 273 | + |
| 274 | +She notices the same setTimeout retry pattern: |
| 275 | + |
| 276 | +``` |
| 277 | +$ smriti search "setTimeout retry" --category bug |
| 278 | +``` |
| 279 | + |
| 280 | +Her earlier finding surfaces. She already knows the fix. |
| 281 | + |
| 282 | +--- |
| 283 | + |
| 284 | +## The Commands |
| 285 | + |
| 286 | +```bash |
| 287 | +# After a deep session — capture everything |
| 288 | +smriti ingest claude |
| 289 | + |
| 290 | +# Share structured knowledge with the team |
| 291 | +smriti share --project payments --segmented |
| 292 | + |
| 293 | +# Commit shared knowledge to git |
| 294 | +cd /path/to/payments |
| 295 | +git add .smriti/ |
| 296 | +git commit -m "docs: share payment service review findings" |
| 297 | + |
| 298 | +# Teammates sync the knowledge |
| 299 | +smriti sync --project payments |
| 300 | + |
| 301 | +# Search across all your sessions |
| 302 | +smriti search "race condition" --project payments |
| 303 | + |
| 304 | +# Get synthesized answers from memory |
| 305 | +smriti recall "how should we handle retries" --synthesize |
| 306 | + |
| 307 | +# Check what you've captured |
| 308 | +smriti status |
| 309 | +``` |
| 310 | + |
| 311 | +--- |
| 312 | + |
| 313 | +## What Makes This Different |
| 314 | + |
| 315 | +| Without Smriti | With Smriti | |
| 316 | +|---|---| |
| 317 | +| Session transcript sits in `~/.claude/` forever | Searchable, indexed, synthesizable memory | |
| 318 | +| Knowledge dies when the session closes | Knowledge persists across sessions and engineers | |
| 319 | +| Teammates start from scratch | Teammates find existing analysis instantly | |
| 320 | +| "Why did we decide X?" — nobody remembers | `smriti recall "why X" --synthesize` | |
| 321 | +| Deep dives produce code changes only | Deep dives produce code changes + documentation | |
| 322 | + |
| 323 | +The session is ephemeral. The knowledge doesn't have to be. |
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