diff --git a/changelog.mdx b/changelog.mdx
index 24d0a20b..72d4a464 100644
--- a/changelog.mdx
+++ b/changelog.mdx
@@ -16,6 +16,30 @@ in `automation/changelog-notes.md`.
 
 {/* CHANGELOG:AUTOGEN:START — edit scripts/build_changelog.py or automation/changelog-notes.md, not this region */}
 
+<Update label="September 2026" tags={["TypeScript", "Rust"]}>
+  ## TypeScript
+
+  | Package | Version |
+  |---------|---------|
+  | `@resq-systems/map` | 4.0.0 |
+  | `@resq-systems/analytics` | 3.1.0 |
+  | `@resq-systems/email-templates` | 1.2.0 |
+  | `@resq-systems/ui` | 0.42.0 |
+  | `@resq-systems/constants` | 0.7.0 |
+  | `@resq-systems/nav` | 0.2.0 |
+
+  ## Rust
+
+  | Package | Version |
+  |---------|---------|
+  | `resq-cli` | 0.4.7 |
+  | `resq-bin`, `resq-clean`, `resq-flame` | 0.1.26 |
+  | `resq-perf` | 0.1.22 |
+  | `resq-tui` | 0.1.18 |
+  | `resq-dsa` | 0.1.4 |
+  | `resq-ai` | 0.1.3 |
+</Update>
+
 <Update label="August 2026" tags={["TypeScript", "Rust"]}>
   ## TypeScript
 
@@ -25,8 +49,9 @@ in `automation/changelog-notes.md`.
   | `@resq-systems/security` | 2.1.0 |
   | `@resq-systems/analytics`, `@resq-systems/http` | 2.0.2 |
   | `@resq-systems/map` | 2.0.0 |
+  | `@resq-systems/email-templates` | 1.1.0 |
   | `@resq-systems/ui` | 0.41.1 |
-  | `@resq-systems/helpers` | 0.6.0 |
+  | `@resq-systems/constants`, `@resq-systems/helpers` | 0.6.0 |
   | `@resq-systems/rate-limiting` | 0.4.3 |
   | `@resq-systems/telemetry` | 0.3.0 |
   | `@resq-systems/types` | 0.2.0 |
@@ -35,9 +60,9 @@ in `automation/changelog-notes.md`.
 
   | Package | Version |
   |---------|---------|
-  | `resq-cli` | 0.4.0 |
-  | `resq-bin`, `resq-clean`, `resq-flame`, `resq-perf` | 0.1.19 |
-  | `resq-tui` | 0.1.11 |
+  | `resq-cli` | 0.4.1 |
+  | `resq-bin`, `resq-clean`, `resq-flame`, `resq-perf` | 0.1.20 |
+  | `resq-tui` | 0.1.12 |
   | `resq-ai` | 0.1.1 |
 </Update>
 
@@ -71,7 +96,7 @@ in `automation/changelog-notes.md`.
 
   | Package | Version |
   |---------|---------|
-  | `resq-bin`, `resq-clean`, `resq-deploy`, `resq-flame`, `resq-health`, `resq-logs`, `resq-perf` | 0.1.18 |
+  | `resq-bin`, `resq-clean`, `resq-flame`, `resq-perf` | 0.1.18 |
   | `resq-tui` | 0.1.10 |
 </Update>
 
@@ -80,7 +105,7 @@ in `automation/changelog-notes.md`.
 
   | Package | Version |
   |---------|---------|
-  | `resq-bin`, `resq-clean`, `resq-deploy`, `resq-flame`, `resq-health`, `resq-logs`, `resq-perf` | 0.1.17 |
+  | `resq-bin`, `resq-clean`, `resq-flame`, `resq-perf` | 0.1.17 |
   | `resq-tui` | 0.1.9 |
 </Update>
 
@@ -96,12 +121,12 @@ in `automation/changelog-notes.md`.
 
   | Package | Version |
   |---------|---------|
-  | `resq-bin`, `resq-clean`, `resq-deploy`, `resq-flame`, `resq-health`, `resq-logs`, `resq-perf` | 0.1.16 |
+  | `resq-bin`, `resq-clean`, `resq-flame`, `resq-perf` | 0.1.16 |
   | `resq-tui` | 0.1.8 |
   | `resq-dsa` | 0.1.3 |
 </Update>
 
-<Update label="April 2026" tags={["TypeScript", "Python", "Rust", ".NET"]}>
+<Update label="April 2026" tags={["TypeScript", "Rust", ".NET"]}>
   **Rust CLI tools renamed.** The seven CLI tools were renamed on 3 April 2026.
   The old crate names stopped at `0.1.9` and are no longer published; the new
   names continue the version series.
@@ -122,19 +147,12 @@ in `automation/changelog-notes.md`.
   |---------|---------|
   | `@resq-sw/logger`, `@resq-sw/rate-limiting` | 0.1.1 |
 
-  ## Python
-
-  | Package | Version |
-  |---------|---------|
-  | `resq-mcp` | 1.3.4 |
-
   ## Rust
 
   | Package | Version |
   |---------|---------|
   | `resq-cli` | 0.2.6 |
-  | `resq-bin`, `resq-clean`, `resq-deploy`, `resq-flame`, `resq-health`, `resq-logs`, `resq-perf` | 0.1.15 |
-  | `resq-bin-explorer`, `resq-cleanup`, `resq-deploy-cli`, `resq-flamegraph`, `resq-health-checker`, `resq-log-viewer`, `resq-perf-monitor` | 0.1.10 |
+  | `resq-bin`, `resq-clean`, `resq-flame`, `resq-perf` | 0.1.15 |
   | `resq-tui` | 0.1.7 |
   | `resq-dsa` | 0.1.2 |
   | `resq-ai` | 0.1.0 |
@@ -158,7 +176,6 @@ in `automation/changelog-notes.md`.
   | Package | Version |
   |---------|---------|
   | `resq-cli` | 0.2.3 |
-  | `resq-bin-explorer`, `resq-cleanup`, `resq-deploy-cli`, `resq-flamegraph`, `resq-health-checker`, `resq-log-viewer`, `resq-perf-monitor` | 0.1.8 |
   | `resq-tui` | 0.1.4 |
   | `resq-dsa` | 0.1.1 |
 
diff --git a/scripts/build_changelog.py b/scripts/build_changelog.py
index b64703f0..57db070d 100644
--- a/scripts/build_changelog.py
+++ b/scripts/build_changelog.py
@@ -25,6 +25,9 @@
 import re
 import subprocess
 import sys
+import urllib.error
+import urllib.parse
+import urllib.request
 
 # repo -> (sidebar label/tag, how tags encode the package name, single-pkg name)
 #   "scoped"   -> @scope/name@version   (npm)
@@ -40,6 +43,24 @@
 }
 ECOSYSTEM_ORDER = ["npm", "pypi", "crates", "dotnet-sdk", "vcpkg"]
 
+# repo -> (registry, package to query for "single"-mode repos)
+#
+# Tags are not proof of publication. A repo-level tag like v0.1.0 in a
+# "single"-mode repo parses as a package release even when no such package
+# version was ever pushed, which is how resq-mcp 0.1.0 and .NET 0.2.0 reached
+# the changelog: neither exists (PyPI starts at 0.3.1, NuGet at 0.3.0). Every
+# derived version is checked against the registry before it is rendered.
+#
+# vcpkg is a port collection with no version registry to query, so it is
+# exempt rather than silently dropped.
+REGISTRY = {
+    "npm": ("npm", None),
+    "pypi": ("pypi", "resq-mcp"),
+    "crates": ("crates", None),
+    "dotnet-sdk": ("nuget", "ResQ.Core"),
+    "vcpkg": (None, None),
+}
+
 # Scope renames: a package under the old scope is dropped from a month's table
 # only when its counterpart under the new scope shipped that same month. This
 # hides the abandoned-scope tail (e.g. @resq-sw/http's final release in July,
@@ -139,7 +160,125 @@ def load_releases(releases_file: str | None) -> list[dict]:
     return out
 
 
-def latest_by_month(releases: list[dict]) -> dict[str, dict[str, dict[str, str]]]:
+_PUBLISHED: dict[tuple[str, str], set[str] | None] = {}
+
+
+def _fetch(url: str) -> dict | None:
+    """Return parsed JSON, {} for 404 (absent), or None if the lookup failed."""
+    req = urllib.request.Request(url, headers={"User-Agent": "resq-docs-changelog"})
+    try:
+        with urllib.request.urlopen(req, timeout=20) as r:
+            return json.loads(r.read().decode("utf-8"))
+    except urllib.error.HTTPError as e:
+        if e.code == 404:
+            return {}
+        print(f"registry lookup failed ({e.code}): {url}", file=sys.stderr)
+        return None
+    except Exception as e:  # network/DNS/timeout
+        print(f"registry lookup failed ({e}): {url}", file=sys.stderr)
+        return None
+
+
+def published_versions(registry: str, pkg: str) -> set[str] | None:
+    """Versions actually published for pkg, or None if the registry was unreachable."""
+    key = (registry, pkg)
+    if key in _PUBLISHED:
+        return _PUBLISHED[key]
+    if registry == "npm":
+        d = _fetch(f"https://registry.npmjs.org/{urllib.parse.quote(pkg, safe='@')}")
+        out = set((d or {}).get("versions", {})) if d is not None else None
+    elif registry == "pypi":
+        d = _fetch(f"https://pypi.org/pypi/{urllib.parse.quote(pkg)}/json")
+        out = set((d or {}).get("releases", {})) if d is not None else None
+    elif registry == "crates":
+        d = _fetch(f"https://crates.io/api/v1/crates/{urllib.parse.quote(pkg)}")
+        out = {v["num"] for v in (d or {}).get("versions", [])} if d is not None else None
+    elif registry == "nuget":
+        d = _fetch(
+            f"https://api.nuget.org/v3-flatcontainer/{urllib.parse.quote(pkg.lower())}/index.json"
+        )
+        out = set((d or {}).get("versions", [])) if d is not None else None
+    else:
+        out = None
+    _PUBLISHED[key] = out
+    return out
+
+
+def _normalize_nuget_version(v: str) -> str:
+    """NuGet normalizes versions: lowercased, leading zeros stripped, and a zero-valued
+    fourth (revision) segment dropped. Comparing in this form keeps a tag like `0.6.0.0`
+    matching the index's `0.6.0`, so a purely cosmetic difference never looks 'unpublished'.
+    """
+    v = v.strip().lower()
+    core, _, pre = v.partition("-")
+    parts = core.split(".")
+    while len(parts) > 3 and parts[-1] in ("0", ""):
+        parts.pop()
+    parts = [str(int(p)) if p.isdigit() else p for p in parts]
+    core = ".".join(parts)
+    return f"{core}-{pre}" if pre else core
+
+
+def _nuget_version_exists(pkg: str, ver: str) -> bool | None:
+    """Confirm one NuGet version directly. The flat-container index can lag behind a
+    just-published version during propagation (NuGet/NuGetGallery#3455), so an index-only
+    miss is not proof of absence. Returns True (present), False (a 404 confirms absent), or
+    None (inconclusive -> the caller should fail open).
+    """
+    p = urllib.parse.quote(pkg.lower())
+    v = urllib.parse.quote(_normalize_nuget_version(ver))
+    url = f"https://api.nuget.org/v3-flatcontainer/{p}/{v}/{p}.{v}.nupkg"
+    req = urllib.request.Request(
+        url, method="HEAD", headers={"User-Agent": "resq-docs-changelog"}
+    )
+    try:
+        with urllib.request.urlopen(req, timeout=20):
+            return True
+    except urllib.error.HTTPError as e:
+        return False if e.code == 404 else None
+    except Exception:  # network/DNS/timeout
+        return None
+
+
+def is_published(repo: str, pkg: str | None, ver: str) -> bool:
+    """True unless the registry positively says this version was never published.
+
+    Unreachable registries and registry-less ecosystems fail open: a transient
+    network error must not silently erase real releases from the changelog.
+    """
+    registry, probe = REGISTRY.get(repo, (None, None))
+    if registry is None:
+        return True
+    target = pkg or probe
+    if not target:
+        return True
+    known = published_versions(registry, target)
+    if known is None:
+        return True
+    if ver in known:
+        return True
+    if registry == "nuget":
+        # NuGet normalizes versions, and its flat-container index can lag behind a
+        # just-published version during propagation, so neither a formatting
+        # difference nor an index-only miss proves the release never shipped. Match
+        # on the normalized form, then, if still absent, confirm the exact version
+        # directly before dropping it.
+        norm = _normalize_nuget_version(ver)
+        if any(_normalize_nuget_version(k) == norm for k in known):
+            return True
+        if _nuget_version_exists(target, ver) is not False:
+            return True
+    print(
+        f"dropping unpublished {repo} release: {target} {ver} "
+        f"(not in {registry})",
+        file=sys.stderr,
+    )
+    return False
+
+
+def latest_by_month(
+    releases: list[dict], verify: bool = True
+) -> dict[str, dict[str, dict[str, str]]]:
     """month 'YYYY-MM' -> repo -> package -> highest version released that month."""
     tree: dict[str, dict[str, dict[str, str]]] = {}
     for rel in releases:
@@ -150,6 +289,8 @@ def latest_by_month(releases: list[dict]) -> dict[str, dict[str, dict[str, str]]
         if not parsed:
             continue
         pkg, ver = parsed
+        if verify and not is_published(repo, pkg, ver):
+            continue
         month = rel["published_at"][:7]
         by_pkg = tree.setdefault(month, {}).setdefault(repo, {})
         if pkg not in by_pkg or version_key(ver) > version_key(by_pkg[pkg]):
@@ -254,11 +395,18 @@ def main() -> int:
     parser.add_argument(
         "--check", action="store_true", help="exit 1 if changelog.mdx is not up to date"
     )
+    parser.add_argument(
+        "--no-verify-registry",
+        action="store_true",
+        help="skip checking each version against its package registry "
+        "(implied by --releases-file, which is for offline runs)",
+    )
     args = parser.parse_args()
 
     root = args.root.resolve()
     releases = load_releases(args.releases_file)
-    tree = latest_by_month(releases)
+    verify = not (args.no_verify_registry or args.releases_file)
+    tree = latest_by_month(releases, verify=verify)
     notes = load_notes(root)
     region = render(tree, notes)