diff --git a/apps/web/src/components/AgentDetailsPanel.tsx b/apps/web/src/components/AgentDetailsPanel.tsx
new file mode 100644
index 0000000..6086f3d
--- /dev/null
+++ b/apps/web/src/components/AgentDetailsPanel.tsx
@@ -0,0 +1,230 @@
+import { useState, useEffect } from "react";
+import { Link } from "@tanstack/react-router";
+import { trpc } from "@/lib/trpc";
+import { cn } from "@/lib/utils";
+import { Skeleton } from "@/components/Skeleton";
+import { Button } from "@/components/ui/button";
+import { StatusDot } from "@/components/StatusDot";
+import { formatRelativeTime } from "@/lib/utils";
+import { modeLabel } from "@/lib/labels";
+
+export function AgentDetailsPanel({ agentId }: { agentId: string }) {
+  return (
+    <div className="h-full overflow-y-auto p-4 space-y-6">
+      <section>
+        <h3 className="text-xs font-semibold uppercase tracking-wide text-muted-foreground mb-3">Metadata</h3>
+        <MetadataSection agentId={agentId} />
+      </section>
+      <section>
+        <h3 className="text-xs font-semibold uppercase tracking-wide text-muted-foreground mb-3">Input Files</h3>
+        <InputFilesSection agentId={agentId} />
+      </section>
+      <section>
+        <h3 className="text-xs font-semibold uppercase tracking-wide text-muted-foreground mb-3">Effective Prompt</h3>
+        <EffectivePromptSection agentId={agentId} />
+      </section>
+    </div>
+  );
+}
+
+function MetadataSection({ agentId }: { agentId: string }) {
+  const query = trpc.getAgent.useQuery({ id: agentId });
+
+  if (query.isLoading) {
+    return (
+      <div className="space-y-2">
+        {Array.from({ length: 5 }).map((_, i) => (
+          <Skeleton key={i} variant="line" />
+        ))}
+      </div>
+    );
+  }
+
+  if (query.isError) {
+    return (
+      <div className="space-y-2">
+        <p className="text-sm text-destructive">{query.error.message}</p>
+        <Button variant="outline" size="sm" onClick={() => void query.refetch()}>Retry</Button>
+      </div>
+    );
+  }
+
+  const agent = query.data;
+  if (!agent) return null;
+
+  const showExitCode = !['idle', 'running', 'waiting_for_input'].includes(agent.status);
+
+  const rows: Array<{ label: string; value: React.ReactNode }> = [
+    {
+      label: 'Status',
+      value: (
+        <span className="flex items-center gap-1.5">
+          <StatusDot status={agent.status} size="sm" />
+          {agent.status}
+        </span>
+      ),
+    },
+    {
+      label: 'Mode',
+      value: modeLabel(agent.mode),
+    },
+    {
+      label: 'Provider',
+      value: agent.provider,
+    },
+    {
+      label: 'Initiative',
+      value: agent.initiativeId ? (
+        <Link
+          to="/initiatives/$initiativeId"
+          params={{ initiativeId: agent.initiativeId }}
+          className="underline underline-offset-2"
+        >
+          {(agent as { initiativeName?: string | null }).initiativeName ?? agent.initiativeId}
+        </Link>
+      ) : '—',
+    },
+    {
+      label: 'Task',
+      value: (agent as { taskName?: string | null }).taskName ?? (agent.taskId ? agent.taskId : '—'),
+    },
+    {
+      label: 'Created',
+      value: formatRelativeTime(String(agent.createdAt)),
+    },
+  ];
+
+  if (showExitCode) {
+    rows.push({
+      label: 'Exit Code',
+      value: (
+        <span className={agent.exitCode === 1 ? 'text-destructive' : ''}>
+          {agent.exitCode ?? '—'}
+        </span>
+      ),
+    });
+  }
+
+  return (
+    <div>
+      {rows.map(({ label, value }) => (
+        <div key={label} className="flex items-center gap-4 py-1.5 border-b border-border/30 last:border-0">
+          <span className="w-28 shrink-0 text-xs text-muted-foreground">{label}</span>
+          <span className="text-sm">{value}</span>
+        </div>
+      ))}
+    </div>
+  );
+}
+
+function InputFilesSection({ agentId }: { agentId: string }) {
+  const query = trpc.getAgentInputFiles.useQuery({ id: agentId });
+  const [selectedFile, setSelectedFile] = useState<string | null>(null);
+
+  useEffect(() => {
+    setSelectedFile(null);
+  }, [agentId]);
+
+  useEffect(() => {
+    if (!query.data?.files) return;
+    if (selectedFile !== null) return;
+    const manifest = query.data.files.find(f => f.name === 'manifest.json');
+    setSelectedFile(manifest?.name ?? query.data.files[0]?.name ?? null);
+  }, [query.data?.files]);
+
+  if (query.isLoading) {
+    return (
+      <div className="space-y-2">
+        <Skeleton variant="line" />
+        <Skeleton variant="line" />
+        <Skeleton variant="line" />
+      </div>
+    );
+  }
+
+  if (query.isError) {
+    return (
+      <div className="space-y-2">
+        <p className="text-sm text-destructive">{query.error.message}</p>
+        <Button variant="outline" size="sm" onClick={() => void query.refetch()}>Retry</Button>
+      </div>
+    );
+  }
+
+  const data = query.data;
+  if (!data) return null;
+
+  if (data.reason === 'worktree_missing') {
+    return <p className="text-sm text-muted-foreground">Worktree no longer exists — input files unavailable</p>;
+  }
+
+  if (data.reason === 'input_dir_missing') {
+    return <p className="text-sm text-muted-foreground">Input directory not found — this agent may not have received input files</p>;
+  }
+
+  const { files } = data;
+
+  if (files.length === 0) {
+    return <p className="text-sm text-muted-foreground">No input files found</p>;
+  }
+
+  return (
+    <div className="flex flex-col md:flex-row gap-2 min-h-0">
+      {/* File list */}
+      <div className="md:w-48 shrink-0 overflow-y-auto space-y-0.5">
+        {files.map(file => (
+          <button
+            key={file.name}
+            onClick={() => setSelectedFile(file.name)}
+            className={cn(
+              "w-full text-left px-2 py-1 text-xs rounded truncate",
+              selectedFile === file.name
+                ? "bg-muted font-medium"
+                : "hover:bg-muted/50 text-muted-foreground"
+            )}
+          >
+            {file.name}
+          </button>
+        ))}
+      </div>
+      {/* Content pane */}
+      <pre className="flex-1 text-xs font-mono overflow-auto bg-terminal rounded p-3 min-h-0">
+        {files.find(f => f.name === selectedFile)?.content ?? ''}
+      </pre>
+    </div>
+  );
+}
+
+function EffectivePromptSection({ agentId }: { agentId: string }) {
+  const query = trpc.getAgentPrompt.useQuery({ id: agentId });
+
+  if (query.isLoading) {
+    return <Skeleton variant="rect" className="h-32 w-full" />;
+  }
+
+  if (query.isError) {
+    return (
+      <div className="space-y-2">
+        <p className="text-sm text-destructive">{query.error.message}</p>
+        <Button variant="outline" size="sm" onClick={() => void query.refetch()}>Retry</Button>
+      </div>
+    );
+  }
+
+  const data = query.data;
+  if (!data) return null;
+
+  if (data.reason === 'prompt_not_written') {
+    return <p className="text-sm text-muted-foreground">Prompt file not available — agent may have been spawned before this feature was added</p>;
+  }
+
+  if (data.content) {
+    return (
+      <pre className="text-xs font-mono overflow-y-auto max-h-[400px] bg-terminal rounded p-3 whitespace-pre-wrap">
+        {data.content}
+      </pre>
+    );
+  }
+
+  return null;
+}
diff --git a/apps/web/src/routes/agents.tsx b/apps/web/src/routes/agents.tsx
index 95ff6ce..d03f7a5 100644
--- a/apps/web/src/routes/agents.tsx
+++ b/apps/web/src/routes/agents.tsx
@@ -1,4 +1,4 @@
-import { useState } from "react";
+import { useState, useEffect } from "react";
 import { createFileRoute, useNavigate, useSearch } from "@tanstack/react-router";
 import { motion } from "motion/react";
 import { AlertCircle, RefreshCw, Terminal, Users } from "lucide-react";
@@ -9,8 +9,9 @@ import { Skeleton } from "@/components/Skeleton";
 import { toast } from "sonner";
 import { trpc } from "@/lib/trpc";
 import { AgentOutputViewer } from "@/components/AgentOutputViewer";
+import { AgentDetailsPanel } from "@/components/AgentDetailsPanel";
 import { AgentActions } from "@/components/AgentActions";
-import { formatRelativeTime } from "@/lib/utils";
+import { formatRelativeTime, cn } from "@/lib/utils";
 import { modeLabel } from "@/lib/labels";
 import { StatusDot } from "@/components/StatusDot";
 import { useLiveUpdates } from "@/hooks";
@@ -29,7 +30,12 @@ export const Route = createFileRoute("/agents")({
 
 function AgentsPage() {
   const [selectedAgentId, setSelectedAgentId] = useState<string | null>(null);
+  const [activeTab, setActiveTab] = useState<'output' | 'details'>('output');
   const { filter } = useSearch({ from: "/agents" });
+
+  useEffect(() => {
+    setActiveTab('output');
+  }, [selectedAgentId]);
   const navigate = useNavigate();
 
   // Live updates
@@ -308,15 +314,49 @@ function AgentsPage() {
           )}
         </div>
 
-        {/* Right: Output Viewer */}
+        {/* Right: Output/Details Viewer */}
         <div className="min-h-0 overflow-hidden">
           {selectedAgent ? (
-            <AgentOutputViewer
-              agentId={selectedAgent.id}
-              agentName={selectedAgent.name}
-              status={selectedAgent.status}
-              onStop={handleStop}
-            />
+            <div className="flex flex-col min-h-0 h-full">
+              {/* Tab bar */}
+              <div className="flex shrink-0 border-b border-terminal-border">
+                <button
+                  className={cn(
+                    "px-4 py-2 text-sm font-medium",
+                    activeTab === 'output'
+                      ? "border-b-2 border-primary text-foreground"
+                      : "text-muted-foreground hover:text-foreground"
+                  )}
+                  onClick={() => setActiveTab('output')}
+                >
+                  Output
+                </button>
+                <button
+                  className={cn(
+                    "px-4 py-2 text-sm font-medium",
+                    activeTab === 'details'
+                      ? "border-b-2 border-primary text-foreground"
+                      : "text-muted-foreground hover:text-foreground"
+                  )}
+                  onClick={() => setActiveTab('details')}
+                >
+                  Details
+                </button>
+              </div>
+              {/* Panel content */}
+              <div className="flex-1 min-h-0 overflow-hidden">
+                {activeTab === 'output' ? (
+                  <AgentOutputViewer
+                    agentId={selectedAgent.id}
+                    agentName={selectedAgent.name}
+                    status={selectedAgent.status}
+                    onStop={handleStop}
+                  />
+                ) : (
+                  <AgentDetailsPanel agentId={selectedAgent.id} />
+                )}
+              </div>
+            </div>
           ) : (
             <div className="flex h-full flex-col items-center justify-center gap-3 rounded-lg border border-dashed">
               <Terminal className="h-10 w-10 text-muted-foreground/30" />
diff --git a/docs/frontend.md b/docs/frontend.md
index 523bdbf..f538920 100644
--- a/docs/frontend.md
+++ b/docs/frontend.md
@@ -44,6 +44,7 @@ Use `mapEntityStatus(rawStatus)` from `StatusDot.tsx` to convert raw entity stat
 |-------|-----------|---------|
 | `/` | `routes/index.tsx` | Dashboard / initiative list |
 | `/initiatives/$id` | `routes/initiatives/$initiativeId.tsx` | Initiative detail (tabbed) |
+| `/agents` | `routes/agents.tsx` | Agent list with Output / Details tab panel |
 | `/settings` | `routes/settings/index.tsx` | Settings page |
 
 ## Initiative Detail Tabs
@@ -54,7 +55,7 @@ The initiative detail page has three tabs managed via local state (not URL param
 2. **Execution Tab** — Pipeline visualization, phase management, task dispatch
 3. **Review Tab** — Pending proposals from agents
 
-## Component Inventory (73 components)
+## Component Inventory (74 components)
 
 ### Core Components (`src/components/`)
 | Component | Purpose |
@@ -66,6 +67,7 @@ The initiative detail page has three tabs managed via local state (not URL param
 | `StatusBadge` | Colored badge using status tokens |
 | `TaskRow` | Task list item with status, priority, category |
 | `QuestionForm` | Agent question form with options |
+| `AgentDetailsPanel` | Details tab for agent right-panel: metadata, input files, effective prompt |
 | `InboxDetailPanel` | Agent message detail + response form |
 | `ProjectPicker` | Checkbox list for project selection |
 | `RegisterProjectDialog` | Dialog to register new git project |