diff --git a/AGENTS.md b/AGENTS.md
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+# AGENTS.md
+
+Harness-agnostic entry point: read by any agent harness that loads `AGENTS.md`
+(kilo, opencode, Claude, Cursor, ...).
+
+## Changelog fragments
+
+A non-test change under `tinyagentos/` or `desktop/src/` requires a
+`changelog.d/<pr>-<slug>.md` fragment (or a `CHANGELOG.md` line) in the same
+PR. The single-source rule lives in [`docs/changelog-fragments.md`](docs/changelog-fragments.md)
+and is summarized in [`CONTRIBUTING.md`](CONTRIBUTING.md) (the "Changelog" section).
diff --git a/CLAUDE.md b/CLAUDE.md
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+# CLAUDE.md
+
+Loaded by the Claude CLI / Claude Code agent when present at the repo root.
+
+## Changelog fragments
+
+A non-test change under `tinyagentos/` or `desktop/src/` requires a
+`changelog.d/<pr>-<slug>.md` fragment (or a `CHANGELOG.md` line) in the same
+PR. The single-source rule lives in [`docs/changelog-fragments.md`](docs/changelog-fragments.md)
+and is summarized in [`CONTRIBUTING.md`](CONTRIBUTING.md) (the "Changelog" section).