diff --git a/crates/plannotator-tui-hosts/src/lib.rs b/crates/plannotator-tui-hosts/src/lib.rs
index 33f9c7a..83a19c5 100644
--- a/crates/plannotator-tui-hosts/src/lib.rs
+++ b/crates/plannotator-tui-hosts/src/lib.rs
@@ -157,9 +157,9 @@ pub fn detect_host(env: impl Fn(&str) -> Option<String>) -> Result<Host, HostErr
         return Ok(Host::Copilot);
     }
     let ai_agent = env("AI_AGENT").map(|v| v.trim().to_ascii_lowercase());
-    // Oh My Pi is a pi harness: it reuses pi's `PI_CODING_AGENT` flag, so its own name must
-    // be checked before pi's flag. `OMPCODE` is exported into every shell OMP spawns, which is
-    // why Plannotator checks it last of all the markers.
+    // Oh My Pi exports `OMPCODE=1` (and `CLAUDECODE=1`) into the shells it spawns and no
+    // pi marker (verified in oh-my-pi `packages/utils/src/procmgr.ts`), so it is found by
+    // `OMPCODE` below; `AI_AGENT=omp` is accepted in case a future version adds it.
     if ai_agent.as_deref() == Some("omp") {
         return Ok(Host::Omp);
     }
diff --git a/crates/plannotator-tui/src/last/locate.rs b/crates/plannotator-tui/src/last/locate.rs
index 0a20b24..66d90f5 100644
--- a/crates/plannotator-tui/src/last/locate.rs
+++ b/crates/plannotator-tui/src/last/locate.rs
@@ -71,9 +71,8 @@ pub(crate) fn locate(options: &LastOptions) -> Result<Located> {
             let Some(id) = options.session_id.as_deref().filter(|s| !s.trim().is_empty()) else {
                 bail!("hermes needs a session id (Herdr provides it; or pass --session-id)");
             };
-            let db = std::env::var_os("HERMES_HOME")
-                .map_or_else(|| home().join(".hermes"), PathBuf::from)
-                .join(hermes::DB_FILE);
+            let db =
+                std::env::var_os("HERMES_HOME").map_or_else(hermes_home, PathBuf::from).join(hermes::DB_FILE);
             let messages = hermes::messages_for_session(&db, id, pick)?;
             (db, messages)
         }
@@ -150,6 +149,20 @@ pub(crate) fn screen_fallback(env: &crate::herdr::context::HerdrEnv) -> Option<D
     ))
 }
 
+/// Hermes' platform default (`hermes_constants.py`): `%LOCALAPPDATA%\hermes` on Windows,
+/// `~/.hermes` elsewhere.
+fn hermes_home() -> PathBuf {
+    #[cfg(windows)]
+    {
+        let base = std::env::var_os("LOCALAPPDATA")
+            .filter(|v| !v.is_empty())
+            .map_or_else(|| home().join("AppData").join("Local"), PathBuf::from);
+        return base.join("hermes");
+    }
+    #[cfg(not(windows))]
+    home().join(".hermes")
+}
+
 fn home() -> PathBuf {
     std::env::home_dir().unwrap_or_else(|| PathBuf::from("/"))
 }
diff --git a/docs/decisions.md b/docs/decisions.md
index 8d97c9f..b128f08 100644
--- a/docs/decisions.md
+++ b/docs/decisions.md
@@ -320,3 +320,12 @@ beats touching a running agent's store), and issues one query over
 (`kind: path | id`) rather than host+pid discovery; a transcript path handed over without a
 host name is recognised by its first lines (`sniff`), so any Herdr-integrated agent that
 writes one of the known formats works without a host table entry.
+
+Source-verified 2026-08-29 against `NousResearch/hermes-agent` (`hermes_state_common.py`,
+`hermes_state.py`, `hermes_state_search.py`, `hermes_constants.py`) and `oh-my-pi`
+(`packages/utils/src/procmgr.ts`): Hermes writes `messages.timestamp` with `time.time()`
+(Unix seconds); `active=0, compacted=0` rows are rewinds the user took back and
+`active=0, compacted=1` rows are compaction archives, so `active = 1` is the right filter;
+the session id Herdr reports is `sessions.id`; `HERMES_HOME` else `~/.hermes`
+(`%LOCALAPPDATA%\hermes` on Windows). omp exports only `OMPCODE=1` and `CLAUDECODE=1` to
+child shells, no pi marker, so the marker chain reaches `OMPCODE` correctly.