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+# Lesson-0001: Enumerate ALL byte-asserted anchors across ALL test suites before compressing agents/*.md
+
+Date: 2026-09-12
+Author: orchestrator
+Context: Semantic compression of agents/orchestrator.md (66,782 → 54,932 chars, behavior preserved)
+Recurring: yes (any future compression of agents/*.md)
+
+## What was learned
+
+When compressing or extracting content from any `agents/*.md` prompt, the compression brief must
+enumerate every `grep -qF` / byte-exact string asserted against that file across **ALL** test
+suites — not only the suites the brief happens to name. In this task the Architect's anchor matrix
+covered test-agent-architecture T01–T09/T13–T15/T17, test-integration I06–I08/I11/I12, memory
+T08/T09, repo T05 — but omitted test-path-resolution T01's canonical runtime sentence, which is
+asserted against `agents/*.md` by a different suite. The compression removed the sentence's
+second/third clauses to docs/OPERATIONS_REFERENCE.md, leaving only the first clause, and
+`test-path-resolution T01` failed (suite went 7/8). Tester caught it; the fix restored the full
+byte-exact sentence.
+
+## Application
+
+- Before any compression of a prompt file: run `grep -rn 'grep.*agents\|-qF' scripts/test-*.sh`
+  (and inspect each suite's anchor list) to build the full byte-string inventory — every string any
+  suite asserts must survive verbatim in the compressed file or remain reachable exactly as asserted.
+- Include `test-path-resolution`, `test-install`, `test-runtime` in the inventory even when the
+  compression brief names only "the document suites".
+- Verify `test-path-resolution T01` (and the full `scripts/test-all.sh`) green pre-commit.
+
+## Evidence
+
+- Failure record: memory/failures/2026-09-12-path-resolution-t01-anchor-gap.md (now closed)
+- scripts/test-path-resolution.sh T01 greps agents/*.md for the full canonical runtime sentence
+- scripts/test-agent-architecture.sh asserts 62 anchors; compression preserved all 67/67 byte-asserted
+  strings; `bash scripts/test-all.sh` → 8/8 PASS (105 checks)
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diff --git a/memory/lessons/README.md b/memory/lessons/README.md
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@@ -27,4 +27,4 @@ Recurring: yes | no
 
 ## Index
 
-_No lessons recorded yet._
+- [Lesson-0001: Enumerate ALL byte-asserted anchors across ALL test suites before compressing agents/*.md](2026-09-12-anchor-enumeration-before-compression.md)