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+---
+date: 2026-05-28
+run_started_utc: 23:00:00
+sources_scanned: 6
+sources_unreachable: 1
+items_considered: 5
+items_opened_pr: 1
+items_deferred: 0
+items_out_of_scope: 2
+prs_opened: [20]
+---
+
+# 2026-05-28 — Daily improvement routine
+
+## Summary
+
+Claude Opus 4.8 shipped today (2026-05-28) with a new `effort` parameter and 4× fewer missed code flaws — a direct upgrade to CSIS's Builder checkpoint. All other in-window items from this source cycle had already been covered by PRs from earlier runs (#8, #15, #16, #18).
+
+## Items considered
+
+### opened-PR — Introducing Claude Opus 4.8
+- URL: https://www.anthropic.com/news/claude-opus-4-8
+- Source: anthropic.com/news, published 2026-05-28
+- Theme: 6 — Substrate / capability boundaries (also Theme 2 — Trust + verification)
+- Touches: `csis/backends/anthropic.py` (_DEFAULT_MODEL_MAP), `csis/backends/base.py` (LLMRequest), `tests/test_backends.py` (new)
+- Size: trivial (100 LOC added across 3 files)
+- Risk: low (no cycle-9 chokepoints touched — Coordinator.__init__, _BackendTracker, writer_iteration_id, promotion CAS all untouched)
+- PR: #20
+
+### out-of-scope — Project Glasswing: An initial update
+- URL: https://www.anthropic.com/research/glasswing-initial-update
+- Reconsidered: skipped — already covered in PR #8 (glasswing-frontier-ranking, 2026-05-23).
+
+### out-of-scope — Coding agents in the social sciences
+- URL: https://www.anthropic.com/research/coding-agents-social-sciences
+- Behavioral adoption study (survey of 1,260 social scientists). No technical agent architecture content. Does not map to any of the seven CSIS themes.
+
+### reconsidered: skipped — How we contain Claude across products
+- URL: https://www.anthropic.com/engineering/how-we-contain-claude
+- Already covered in PR #15 (external-content-layer, 2026-05-26). No new angle to open.
+
+### reconsidered: skipped — Agent SDK overview
+- URL: https://code.claude.com/docs/en/agent-sdk/overview
+- Already covered in PR #16 (domain-system-prompt, 2026-05-26). No new angle to open.
+
+## Reconsidered from prior runs
+
+None this run. The two prior-run `deferred` items (Managed Agents dreaming preview, Stainless MCP manifest) remain deferred — no new public API surface has appeared for either.
+
+## Sources unreachable
+
+- `platform.claude.com/docs/en` — returned a Not Found / loading-state SPA response (same pattern as prior runs). Subpages reachable via direct URL (fetched model overview via `platform.claude.com/docs/en/docs/about-claude/models/overview`). Counted as 1 partial failure.
diff --git a/brain/routines/index.md b/brain/routines/index.md
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--- a/brain/routines/index.md
+++ b/brain/routines/index.md
@@ -12,3 +12,10 @@ Status values:
 | URL | First seen | Status | Notes |
 |---|---|---|---|
 | (none) | (initial) | quiet-day-empty | Ledger initialized; first real entries land on the routine's first scheduled run. |
+| https://www.anthropic.com/research/glasswing-initial-update | 2026-05-23 | opened-PR | PR #8 glasswing-frontier-ranking |
+| https://www.anthropic.com/news/widening-conversation-ai | 2026-05-24 | opened-PR | PR #10 value-reminder-tripwire (also PR #18 constitution-reminder-tool) |
+| https://code.claude.com/docs/en/changelog | 2026-05-25 | opened-PR | PR #12 event-span-agent-ids, PR #13 critic-effort-levels |
+| https://www.anthropic.com/engineering/how-we-contain-claude | 2026-05-26 | opened-PR | PR #15 external-content-layer |
+| https://code.claude.com/docs/en/agent-sdk/overview | 2026-05-26 | opened-PR | PR #16 domain-system-prompt |
+| https://www.anthropic.com/news/claude-opus-4-8 | 2026-05-28 | opened-PR | PR #20 opus-4-8-effort |
+| https://www.anthropic.com/research/coding-agents-social-sciences | 2026-05-28 | out-of-scope | Behavioral adoption study, no technical CSIS-theme content |