feat(session-historian): cross-platform session history agent and /ce-sessions skill (#534)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

plugins/compound-engineering/agents/research/session-history-scripts/discover-sessions.sh

@@ -0,0 +1,81 @@
+#!/usr/bin/env bash
+# Discover session files across Claude Code, Codex, and Cursor.
+#
+# Usage: discover-sessions.sh <repo-name> <days> [--platform claude|codex|cursor]
+#
+# Outputs one file path per line. Safe in both bash and zsh (all globs guarded).
+# Pass output to extract-metadata.py:
+#   python3 extract-metadata.py --cwd-filter <repo-name> $(bash discover-sessions.sh <repo-name> 7)
+#
+# Arguments:
+#   repo-name  Folder name of the repo (e.g., "my-repo"). Used for directory matching.
+#   days       Scan window in days (e.g., 7). Files older than this are skipped.
+#   --platform Restrict to a single platform. Omit to search all.
+
+set -euo pipefail
+
+REPO_NAME="${1:?Usage: discover-sessions.sh <repo-name> <days> [--platform claude|codex|cursor]}"
+DAYS="${2:?Usage: discover-sessions.sh <repo-name> <days> [--platform claude|codex|cursor]}"
+PLATFORM="${4:-all}"
+
+# Parse optional --platform flag
+shift 2
+while [ $# -gt 0 ]; do
+    case "$1" in
+        --platform) PLATFORM="$2"; shift 2 ;;
+        *) shift ;;
+    esac
+done
+
+# --- Claude Code ---
+discover_claude() {
+    local base="$HOME/.claude/projects"
+    [ -d "$base" ] || return 0
+
+    # Find all project dirs matching repo name
+    for dir in "$base"/*"$REPO_NAME"*/; do
+        [ -d "$dir" ] || continue
+        find "$dir" -maxdepth 1 -name "*.jsonl" -mtime "-${DAYS}" 2>/dev/null
+    done
+}
+
+# --- Codex ---
+discover_codex() {
+    for base in "$HOME/.codex/sessions" "$HOME/.agents/sessions"; do
+        [ -d "$base" ] || continue
+
+        # Use mtime-based discovery (consistent with Claude/Cursor) so that
+        # sessions started before the scan window but still active within it
+        # are not missed.
+        find "$base" -name "*.jsonl" -mtime "-${DAYS}" 2>/dev/null
+    done
+}
+
+# --- Cursor ---
+discover_cursor() {
+    local base="$HOME/.cursor/projects"
+    [ -d "$base" ] || return 0
+
+    for dir in "$base"/*"$REPO_NAME"*/; do
+        [ -d "$dir" ] || continue
+        local transcripts="$dir/agent-transcripts"
+        [ -d "$transcripts" ] || continue
+        find "$transcripts" -name "*.jsonl" -mtime "-${DAYS}" 2>/dev/null
+    done
+}
+
+# --- Dispatch ---
+case "$PLATFORM" in
+    claude)  discover_claude ;;
+    codex)   discover_codex ;;
+    cursor)  discover_cursor ;;
+    all)
+        discover_claude
+        discover_codex
+        discover_cursor
+        ;;
+    *)
+        echo "Unknown platform: $PLATFORM" >&2
+        exit 1
+        ;;
+esac