docs: cycle 2 retrospective — Kimi codebase scanning bottleneck identified

Root cause: Kimi reads entire codebase before editing, consuming timeout.
Fix: pre-extract context into prompt, or use Kimi for reasoning tasks only.

docs/design-log/2026-03-15-cycle2-retro.md

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+# Delegation Cycle 2 — Retrospective
+
+## Date: 2026-03-15
+## Task: #148 split into chunks per Cycle 1 lessons
+
+---
+
+## What Happened
+
+Split #148 into 3 chunks (A: timmy/, B: dashboard/, C: infra+spark/).
+Dispatched Chunk C (4 files, smallest) to Kimi with 180s timeout.
+
+**Result: Kimi timed out again without making any changes.**
+
+Kimi's --print mode spends its time budget on:
+1. Reading all files in the working directory (codebase scanning)
+2. Planning the approach (chain of thought)
+3. Searching the web for best practices
+4. Actually making edits
+
+For this codebase (~8800 SLOC), steps 1-3 consume most of the timeout.
+
+## Root Cause Analysis
+
+**Kimi is not timing out because the task is too big. It's timing out because
+it reads the entire codebase before starting work.**
+
+The 262K context is a trap — Kimi ingests everything it can find, and for a
+project with 200+ files, this planning phase alone can exceed 180s.
+
+## Proposed Fix for Cycle 3
+
+1. **Pre-extract context.** Instead of pointing Kimi at the full repo, give
+   it ONLY the files it needs to edit, as inline code in the prompt.
+2. **Use --add-dir sparingly.** Don't let Kimi see the full src/ tree.
+3. **Consider: do mechanical refactors myself.** sqlite3 context manager
+   conversion is a mechanical find-and-replace pattern. The value of Kimi
+   is in tasks requiring reasoning, not search-and-replace.
+
+## Deliverables
+
+- No new PRs this cycle
+- Lesson: Kimi's planning overhead on large codebases is the real bottleneck
+- #148 remains open — candidate for scripted refactoring or inline-context Kimi task
+
+## Cumulative Stats (Cycles 1+2)
+
+| Metric | Cycle 1 | Cycle 2 | Total |
+|--------|---------|---------|-------|
+| PRs created | 1 | 0 | 1 |
+| Kimi invocations | 4 | 1 | 5 |
+| Kimi timeouts | 3 | 1 | 4 |
+| Kimi successes | 1 | 0 | 1 |
+| Success rate | 25% | 0% | 20% |