diff --git a/CHANGELOG.md b/CHANGELOG.md
index dca7ece..2c7fc72 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,46 @@ Pre-v1.0.0 tags followed the pi npm version (`v{pi_version}[letter]`).
 
 ---
 
+## Unreleased
+
+Staged, not yet tagged — more changes are queued for the next release before CI
+is kicked off.
+
+### Changed
+
+- **mempalace pin `3.5.0` → `3.6.0`** (`Dockerfile.base` `MEMPALACE_VERSION`),
+  in lockstep with opencode-devbox v2.9.0 as the pin's own comment requires.
+  3.6.0 (2026-07-17) is PyPI latest and is additive/reliability only — secure
+  `mempalace serve` remote mode, optional Milvus backend, atomic KG
+  `supersede()`, conversation chronology, mining exclusions, plus recovery and
+  locking fixes. **Reviewed for MCP tool-schema changes before bumping** — that
+  being the exact regression class this pin exists to catch, after an unpinned
+  install once swept in the broken 3.3.x/3.4.0 `diary_write` schema: there are
+  **none**, and nothing touches `diary_write`, so the perl workaround removed in
+  v1.2.2 stays removed. Two fixes are directly relevant to how this image uses
+  mempalace: read-only mode now covers `checkpoint` + `delete_by_source` in
+  `_MUTATING_TOOLS` (#1930), and agent attribution is preserved in
+  `mempalace_checkpoint` (#2023/#2034) — the latter matters because the diary
+  protocol relies on per-agent attribution. Rebuilds the base image.
+
+### Documentation
+
+- Documents **per-variant image description labels** (committed and pushed after
+  the v1.6.4 tag without a changelog entry). Both published variants used to
+  inherit `Dockerfile.base`'s `description="pi-devbox — base image
+  (variant-independent)"`, so `v1.6.4` and `v1.6.4-studio` both advertised
+  themselves on Docker Hub as *the base image* — misleading, and useless for
+  telling the two apart. Since a `LABEL` cannot branch on `INSTALL_STUDIO`, the
+  text now arrives as a build arg: CI passes a variant-specific string
+  (interpolating `RELEASE_TAG`, `PI_VERSION`, and `STUDIO_TAG` for studio), while
+  the `Dockerfile.variant` default keeps a bare local `docker build` honest
+  rather than misleading. Sets `org.opencontainers.image.title`/`.description`
+  alongside the legacy bare `description` key so both Hub and OCI-aware tooling
+  see it. The ARGs stay in the last-declared block, so the label layer remains
+  the only thing invalidated.
+
+---
+
 ## v1.6.4 — 2026-07-30
 
 Patch release. Headline: **the `fork` tool has never once loaded since v1.0.0**
diff --git a/Dockerfile.base b/Dockerfile.base
index 3cbb3ce..192de33 100644
--- a/Dockerfile.base
+++ b/Dockerfile.base
@@ -367,13 +367,24 @@ ARG INSTALL_MEMPALACE=true
 # diary_write schema. Pinning makes mempalace upgrades a reviewable diff
 # rather than a surprise.
 #
-# 3.5.0 (2026-06) ships the upstream fix for the top-level-anyOf diary_write
+# 3.5.0 (2026-06) shipped the upstream fix for the top-level-anyOf diary_write
 # schema (issue #1728 / PR #1717, merged 2026-06-14): the advertised schema
 # is now `"required": ["agent_name"]` with entry/content enforced at dispatch,
 # which Anthropic's tools API accepts — so the old mcp_server.py perl
-# workaround that used to live below is gone. Keep in lockstep with
-# opencode-devbox when bumping.
-ARG MEMPALACE_VERSION=3.5.0
+# workaround that used to live below is gone.
+#
+# 3.6.0 (2026-07-17, PyPI latest) is additive/reliability only — secure
+# `mempalace serve` remote mode, optional Milvus backend, atomic KG
+# supersede(), conversation chronology, mining exclusions, plus recovery and
+# locking fixes. Reviewed for MCP tool-schema changes before bumping (that
+# being the exact regression class this pin exists to catch): there are NONE,
+# and nothing touches diary_write. Two fixes matter for how this image uses
+# mempalace: read-only mode now covers checkpoint + delete_by_source in
+# _MUTATING_TOOLS (#1930), and agent attribution is preserved in
+# mempalace_checkpoint (#2023/#2034).
+#
+# Keep in lockstep with opencode-devbox when bumping.
+ARG MEMPALACE_VERSION=3.6.0
 ENV UV_TOOL_DIR=/opt/uv-tools
 ENV UV_TOOL_BIN_DIR=/usr/local/bin
 RUN if [ "${INSTALL_MEMPALACE}" = "true" ]; then \