feat: Decisions page — aggregated view of all decision points across traces

Adds /dashboard/decisions page with colored type badges, search,
filters (by type), sort (newest/oldest/costliest), pagination,
and links to parent traces. New /api/decisions endpoint with
Prisma queries. Removes 'Soon' badge from sidebar nav.

apps/web/src/app/api/decisions/route.ts

@@ -0,0 +1,127 @@
+import { NextRequest, NextResponse } from "next/server";
+import { prisma } from "@/lib/prisma";
+import { Prisma } from "@agentlens/database";
+
+export async function GET(request: NextRequest) {
+  try {
+    const { searchParams } = new URL(request.url);
+    const page = parseInt(searchParams.get("page") ?? "1", 10);
+    const limit = parseInt(searchParams.get("limit") ?? "20", 10);
+    const type = searchParams.get("type");
+    const search = searchParams.get("search");
+    const sort = searchParams.get("sort") ?? "newest";
+
+    // Validate pagination
+    if (isNaN(page) || page < 1) {
+      return NextResponse.json(
+        { error: "Invalid page parameter. Must be a positive integer." },
+        { status: 400 }
+      );
+    }
+    if (isNaN(limit) || limit < 1 || limit > 100) {
+      return NextResponse.json(
+        { error: "Invalid limit parameter. Must be between 1 and 100." },
+        { status: 400 }
+      );
+    }
+
+    // Validate type
+    const validTypes = [
+      "TOOL_SELECTION",
+      "ROUTING",
+      "RETRY",
+      "ESCALATION",
+      "MEMORY_RETRIEVAL",
+      "PLANNING",
+      "CUSTOM",
+    ];
+    if (type && !validTypes.includes(type)) {
+      return NextResponse.json(
+        { error: `Invalid type. Must be one of: ${validTypes.join(", ")}` },
+        { status: 400 }
+      );
+    }
+
+    // Validate sort
+    const validSorts = ["newest", "oldest", "costliest"];
+    if (!validSorts.includes(sort)) {
+      return NextResponse.json(
+        { error: `Invalid sort. Must be one of: ${validSorts.join(", ")}` },
+        { status: 400 }
+      );
+    }
+
+    // Build where clause
+    const where: Prisma.DecisionPointWhereInput = {};
+    if (type) {
+      where.type = type as Prisma.EnumDecisionTypeFilter["equals"];
+    }
+    if (search) {
+      where.reasoning = {
+        contains: search,
+        mode: "insensitive",
+      };
+    }
+
+    // Build order by
+    let orderBy: Prisma.DecisionPointOrderByWithRelationInput;
+    switch (sort) {
+      case "oldest":
+        orderBy = { timestamp: "asc" };
+        break;
+      case "costliest":
+        orderBy = { costUsd: "desc" };
+        break;
+      case "newest":
+      default:
+        orderBy = { timestamp: "desc" };
+        break;
+    }
+
+    // Count total
+    const total = await prisma.decisionPoint.count({ where });
+
+    // Pagination
+    const skip = (page - 1) * limit;
+    const totalPages = Math.ceil(total / limit);
+
+    // Fetch decisions with parent trace and span
+    const decisions = await prisma.decisionPoint.findMany({
+      where,
+      include: {
+        trace: {
+          select: {
+            id: true,
+            name: true,
+          },
+        },
+        span: {
+          select: {
+            id: true,
+            name: true,
+          },
+        },
+      },
+      orderBy,
+      skip,
+      take: limit,
+    });
+
+    return NextResponse.json(
+      {
+        decisions,
+        total,
+        page,
+        limit,
+        totalPages,
+      },
+      { status: 200 }
+    );
+  } catch (error) {
+    console.error("Error listing decisions:", error);
+    return NextResponse.json(
+      { error: "Internal server error" },
+      { status: 500 }
+    );
+  }
+}

apps/web/src/app/dashboard/decisions/page.tsx

@@ -0,0 +1,402 @@
+"use client";
+
+import { useState, useEffect, useCallback } from "react";
+import Link from "next/link";
+import {
+  Search,
+  ChevronLeft,
+  ChevronRight,
+  GitBranch,
+  DollarSign,
+  Clock,
+  ArrowRight,
+  Layers,
+} from "lucide-react";
+import { cn, formatRelativeTime } from "@/lib/utils";
+
+type DecisionType =
+  | "TOOL_SELECTION"
+  | "ROUTING"
+  | "RETRY"
+  | "ESCALATION"
+  | "MEMORY_RETRIEVAL"
+  | "PLANNING"
+  | "CUSTOM";
+
+type SortOption = "newest" | "oldest" | "costliest";
+
+interface Decision {
+  id: string;
+  traceId: string;
+  type: DecisionType;
+  reasoning: string | null;
+  chosen: Record<string, unknown>;
+  alternatives: Record<string, unknown>[];
+  contextSnapshot: Record<string, unknown> | null;
+  durationMs: number | null;
+  costUsd: number | null;
+  parentSpanId: string | null;
+  timestamp: string;
+  trace: {
+    id: string;
+    name: string;
+  };
+  span: {
+    id: string;
+    name: string;
+  } | null;
+}
+
+interface DecisionsResponse {
+  decisions: Decision[];
+  total: number;
+  page: number;
+  limit: number;
+  totalPages: number;
+}
+
+const typeConfig: Record<
+  DecisionType,
+  { label: string; bg: string; text: string }
+> = {
+  TOOL_SELECTION: {
+    label: "Tool Selection",
+    bg: "bg-blue-500/10",
+    text: "text-blue-400",
+  },
+  ROUTING: {
+    label: "Routing",
+    bg: "bg-purple-500/10",
+    text: "text-purple-400",
+  },
+  RETRY: {
+    label: "Retry",
+    bg: "bg-amber-500/10",
+    text: "text-amber-400",
+  },
+  ESCALATION: {
+    label: "Escalation",
+    bg: "bg-red-500/10",
+    text: "text-red-400",
+  },
+  MEMORY_RETRIEVAL: {
+    label: "Memory Retrieval",
+    bg: "bg-cyan-500/10",
+    text: "text-cyan-400",
+  },
+  PLANNING: {
+    label: "Planning",
+    bg: "bg-emerald-500/10",
+    text: "text-emerald-400",
+  },
+  CUSTOM: {
+    label: "Custom",
+    bg: "bg-neutral-500/10",
+    text: "text-neutral-400",
+  },
+};
+
+const sortOptions: { value: SortOption; label: string }[] = [
+  { value: "newest", label: "Newest" },
+  { value: "oldest", label: "Oldest" },
+  { value: "costliest", label: "Most Expensive" },
+];
+
+const allTypes: DecisionType[] = [
+  "TOOL_SELECTION",
+  "ROUTING",
+  "RETRY",
+  "ESCALATION",
+  "MEMORY_RETRIEVAL",
+  "PLANNING",
+  "CUSTOM",
+];
+
+function extractChosenName(chosen: Record<string, unknown>): string {
+  if (chosen && typeof chosen === "object") {
+    if (typeof chosen.name === "string") return chosen.name;
+    if (typeof chosen.action === "string") return chosen.action;
+    if (typeof chosen.tool === "string") return chosen.tool;
+    // Fallback: first string value
+    for (const val of Object.values(chosen)) {
+      if (typeof val === "string") return val;
+    }
+  }
+  return "Unknown";
+}
+
+function truncate(text: string, max: number): string {
+  if (text.length <= max) return text;
+  return text.slice(0, max) + "...";
+}
+
+export default function DecisionsPage() {
+  const [decisions, setDecisions] = useState<Decision[]>([]);
+  const [total, setTotal] = useState(0);
+  const [totalPages, setTotalPages] = useState(0);
+  const [currentPage, setCurrentPage] = useState(1);
+  const [isLoading, setIsLoading] = useState(true);
+
+  const [searchQuery, setSearchQuery] = useState("");
+  const [typeFilter, setTypeFilter] = useState<DecisionType | "ALL">("ALL");
+  const [sortFilter, setSortFilter] = useState<SortOption>("newest");
+
+  const fetchDecisions = useCallback(async () => {
+    setIsLoading(true);
+    try {
+      const params = new URLSearchParams();
+      params.set("page", currentPage.toString());
+      params.set("limit", "30");
+
+      if (typeFilter !== "ALL") {
+        params.set("type", typeFilter);
+      }
+      if (searchQuery) {
+        params.set("search", searchQuery);
+      }
+      if (sortFilter !== "newest") {
+        params.set("sort", sortFilter);
+      }
+
+      const res = await fetch(`/api/decisions?${params.toString()}`, {
+        cache: "no-store",
+      });
+
+      if (!res.ok) {
+        throw new Error(`Failed to fetch decisions: ${res.status}`);
+      }
+
+      const data: DecisionsResponse = await res.json();
+      setDecisions(data.decisions);
+      setTotal(data.total);
+      setTotalPages(data.totalPages);
+    } catch (error) {
+      console.error("Error fetching decisions:", error);
+    } finally {
+      setIsLoading(false);
+    }
+  }, [currentPage, typeFilter, searchQuery, sortFilter]);
+
+  useEffect(() => {
+    fetchDecisions();
+  }, [fetchDecisions]);
+
+  useEffect(() => {
+    setCurrentPage(1);
+  }, [searchQuery, typeFilter, sortFilter]);
+
+  const handlePageChange = (newPage: number) => {
+    setCurrentPage(newPage);
+    window.scrollTo({ top: 0, behavior: "smooth" });
+  };
+
+  return (
+    <div className="space-y-6">
+      {/* Header */}
+      <div>
+        <h1 className="text-2xl font-bold text-neutral-100">Decisions</h1>
+        <p className="text-neutral-400 mt-1">
+          {total} decision point{total !== 1 ? "s" : ""} across all traces
+        </p>
+      </div>
+
+      {/* Search and Filters */}
+      <div className="flex flex-col gap-4">
+        <div className="flex flex-col sm:flex-row gap-4">
+          {/* Search */}
+          <div className="relative flex-1">
+            <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-5 h-5 text-neutral-500" />
+            <input
+              type="text"
+              placeholder="Search by reasoning..."
+              value={searchQuery}
+              onChange={(e) => setSearchQuery(e.target.value)}
+              className="w-full pl-10 pr-4 py-3 bg-neutral-900 border border-neutral-800 rounded-lg text-neutral-100 placeholder-neutral-500 focus:outline-none focus:border-emerald-500/50 focus:ring-1 focus:ring-emerald-500/50 transition-all"
+            />
+          </div>
+
+          {/* Type Filter */}
+          <div className="flex items-center gap-3">
+            <select
+              value={typeFilter}
+              onChange={(e) =>
+                setTypeFilter(e.target.value as DecisionType | "ALL")
+              }
+              className="bg-neutral-900 border border-neutral-800 rounded-lg px-3 py-3 text-sm text-neutral-100 focus:outline-none focus:border-emerald-500/50 focus:ring-1 focus:ring-emerald-500/50 transition-all"
+            >
+              <option value="ALL">All Types</option>
+              {allTypes.map((t) => (
+                <option key={t} value={t}>
+                  {typeConfig[t].label}
+                </option>
+              ))}
+            </select>
+
+            {/* Sort */}
+            <select
+              value={sortFilter}
+              onChange={(e) => setSortFilter(e.target.value as SortOption)}
+              className="bg-neutral-900 border border-neutral-800 rounded-lg px-3 py-3 text-sm text-neutral-100 focus:outline-none focus:border-emerald-500/50 focus:ring-1 focus:ring-emerald-500/50 transition-all"
+            >
+              {sortOptions.map((option) => (
+                <option key={option.value} value={option.value}>
+                  {option.label}
+                </option>
+              ))}
+            </select>
+          </div>
+        </div>
+      </div>
+
+      {/* Loading State */}
+      {isLoading && decisions.length === 0 && (
+        <div className="space-y-3">
+          {Array.from({ length: 5 }).map((_, i) => (
+            <div
+              key={i}
+              className="p-5 bg-neutral-900 border border-neutral-800 rounded-xl animate-pulse"
+            >
+              <div className="flex items-center gap-4">
+                <div className="h-6 w-24 bg-neutral-800 rounded-md" />
+                <div className="flex-1">
+                  <div className="h-5 w-48 bg-neutral-800 rounded-md mb-2" />
+                  <div className="h-4 w-96 bg-neutral-800/60 rounded-md" />
+                </div>
+                <div className="h-4 w-16 bg-neutral-800 rounded-md" />
+              </div>
+            </div>
+          ))}
+        </div>
+      )}
+
+      {/* Empty State */}
+      {!isLoading && decisions.length === 0 && (
+        <div className="flex flex-col items-center justify-center py-20 text-center">
+          <div className="w-20 h-20 rounded-2xl bg-neutral-900 border border-neutral-800 flex items-center justify-center mb-6">
+            <GitBranch className="w-10 h-10 text-neutral-600" />
+          </div>
+          <h2 className="text-xl font-semibold text-neutral-100 mb-2">
+            No decision points yet
+          </h2>
+          <p className="text-neutral-400 max-w-md">
+            Decision points will appear here once your agents start making
+            decisions. Send traces with decision data to see them aggregated.
+          </p>
+        </div>
+      )}
+
+      {/* Decision List */}
+      {decisions.length > 0 && (
+        <div className="space-y-3">
+          {decisions.map((decision) => (
+            <DecisionCard key={decision.id} decision={decision} />
+          ))}
+        </div>
+      )}
+
+      {/* Pagination */}
+      {totalPages > 1 && (
+        <div className="flex items-center justify-between pt-6 border-t border-neutral-800">
+          <p className="text-sm text-neutral-500">
+            Page {currentPage} of {totalPages}
+          </p>
+          <div className="flex gap-2">
+            <button
+              disabled={currentPage <= 1}
+              onClick={() => handlePageChange(Math.max(1, currentPage - 1))}
+              className="p-2 rounded-lg border border-neutral-800 text-neutral-400 hover:text-neutral-100 hover:border-neutral-700 disabled:opacity-50 disabled:cursor-not-allowed transition-colors"
+            >
+              <ChevronLeft className="w-5 h-5" />
+            </button>
+            <button
+              disabled={currentPage >= totalPages}
+              onClick={() =>
+                handlePageChange(Math.min(totalPages, currentPage + 1))
+              }
+              className="p-2 rounded-lg border border-neutral-800 text-neutral-400 hover:text-neutral-100 hover:border-neutral-700 disabled:opacity-50 disabled:cursor-not-allowed transition-colors"
+            >
+              <ChevronRight className="w-5 h-5" />
+            </button>
+          </div>
+        </div>
+      )}
+    </div>
+  );
+}
+
+function DecisionCard({ decision }: { decision: Decision }) {
+  const config = typeConfig[decision.type] || typeConfig.CUSTOM;
+  const chosenName = extractChosenName(
+    decision.chosen as Record<string, unknown>
+  );
+
+  return (
+    <div className="group p-5 bg-neutral-900 border border-neutral-800 rounded-xl hover:border-emerald-500/30 hover:bg-neutral-800/50 transition-all duration-200">
+      <div className="flex flex-col lg:flex-row lg:items-center gap-4">
+        {/* Left: Type badge + chosen + reasoning */}
+        <div className="flex-1 min-w-0">
+          <div className="flex items-center gap-3 mb-2">
+            <span
+              className={cn(
+                "inline-flex items-center px-2.5 py-1 rounded-md text-xs font-medium uppercase tracking-wide",
+                config.bg,
+                config.text
+              )}
+            >
+              {config.label}
+            </span>
+            <h3 className="font-semibold text-neutral-100 truncate">
+              {chosenName}
+            </h3>
+          </div>
+
+          {decision.reasoning && (
+            <p className="text-sm text-neutral-400 leading-relaxed">
+              {truncate(decision.reasoning, 120)}
+            </p>
+          )}
+
+          <div className="flex items-center gap-4 mt-2 text-sm text-neutral-500">
+            <span className="flex items-center gap-1.5">
+              <Clock className="w-3.5 h-3.5" />
+              {formatRelativeTime(decision.timestamp)}
+            </span>
+            {decision.alternatives.length > 0 && (
+              <span className="flex items-center gap-1.5">
+                <Layers className="w-3.5 h-3.5" />
+                {decision.alternatives.length} alternative
+                {decision.alternatives.length !== 1 ? "s" : ""}
+              </span>
+            )}
+            {decision.costUsd !== null && decision.costUsd > 0 && (
+              <span className="flex items-center gap-1.5">
+                <DollarSign className="w-3.5 h-3.5" />$
+                {decision.costUsd.toFixed(4)}
+              </span>
+            )}
+            {decision.span && (
+              <span className="flex items-center gap-1.5 text-neutral-500">
+                <GitBranch className="w-3.5 h-3.5" />
+                {decision.span.name}
+              </span>
+            )}
+          </div>
+        </div>
+
+        {/* Right: Trace link */}
+        <div className="flex items-center gap-3 shrink-0">
+          <Link
+            href={`/dashboard/traces/${decision.trace.id}`}
+            onClick={(e) => e.stopPropagation()}
+            className="flex items-center gap-2 px-3 py-2 rounded-lg bg-neutral-800/50 border border-neutral-700/50 text-sm text-neutral-300 hover:text-emerald-400 hover:border-emerald-500/30 transition-all"
+          >
+            <span className="truncate max-w-[180px]">
+              {decision.trace.name}
+            </span>
+            <ArrowRight className="w-4 h-4 shrink-0" />
+          </Link>
+        </div>
+      </div>
+    </div>
+  );
+}

apps/web/src/app/dashboard/layout.tsx

@@ -8,7 +8,6 @@ import {
   GitBranch,
   Settings,
   Menu,
-  X,
   ChevronRight,
 } from "lucide-react";
 import { cn } from "@/lib/utils";
@@ -22,7 +21,7 @@ interface NavItem {
 
 const navItems: NavItem[] = [
   { href: "/dashboard", label: "Traces", icon: Activity },
-  { href: "/dashboard/decisions", label: "Decisions", icon: GitBranch, comingSoon: true },
+  { href: "/dashboard/decisions", label: "Decisions", icon: GitBranch },
   { href: "/dashboard/settings", label: "Settings", icon: Settings, comingSoon: true },
 ];