diff --git a/client/src/pages/SkillsPage.tsx b/client/src/pages/SkillsPage.tsx
index 945e39e..77c0191 100644
--- a/client/src/pages/SkillsPage.tsx
+++ b/client/src/pages/SkillsPage.tsx
@@ -1,5 +1,5 @@
 import { useCallback, useEffect, useMemo, useState } from 'react'
-import { BookMarked, GitFork, Pencil, Plus, Store, Trash2 } from 'lucide-react'
+import { BookMarked, Download, GitFork, Pencil, Plus, Store, Trash2, Upload } from 'lucide-react'
 import { toast } from 'sonner'
 import { AppShell } from '@/components/AppShell'
 import { Badge } from '@/components/ui/badge'
@@ -32,6 +32,7 @@ interface GoldenTest {
 }
 
 interface SkillSummary {
+  id: string
   skillKey: string
   name: string
   version: string
@@ -56,6 +57,11 @@ interface SkillDetail {
   body: string
 }
 
+interface MarketplaceEntry {
+  skill: SkillSummary
+  alreadyInLibrary: boolean
+}
+
 type Mode = 'new' | 'version' | 'edit'
 
 interface FormState {
@@ -92,7 +98,7 @@ const emptyForm = (): FormState => ({
   outputs: '',
   tools: '',
   context: '',
-  visibility: 'public',
+  visibility: 'private',
   minTier: 'free',
   body: '',
   actions: [],
@@ -120,7 +126,7 @@ export function SkillsPage() {
   const organizationId = useAuth((s) => s.organizationId)
   const [tab, setTab] = useState<'library' | 'marketplace'>('library')
   const [skills, setSkills] = useState<SkillSummary[]>([])
-  const [marketplace, setMarketplace] = useState<SkillSummary[]>([])
+  const [marketplace, setMarketplace] = useState<MarketplaceEntry[]>([])
   const [form, setForm] = useState<FormState | null>(null)
   const [busy, setBusy] = useState(false)
 
@@ -129,7 +135,7 @@ export function SkillsPage() {
     try {
       const [lib, market] = await Promise.all([
         api.get<SkillSummary[]>(`/api/skills?organizationId=${organizationId}`),
-        api.get<SkillSummary[]>(`/api/skills/marketplace`),
+        api.get<MarketplaceEntry[]>(`/api/skills/marketplace?organizationId=${organizationId}`),
       ])
       setSkills(lib)
       setMarketplace(market)
@@ -193,6 +199,32 @@ export function SkillsPage() {
     }
   }
 
+  const setListed = async (key: string, version: string, listed: boolean) => {
+    setBusy(true)
+    try {
+      await api.post(`/api/skills/${key}/${listed ? 'publish' : 'unpublish'}`, { organizationId, version })
+      toast.success(listed ? `Published ${key}@${version} to the marketplace.` : `Unlisted ${key}@${version}.`)
+      await load()
+    } catch (err) {
+      toast.error((err as Error).message)
+    } finally {
+      setBusy(false)
+    }
+  }
+
+  const install = async (sourceSkillId: string, name: string) => {
+    setBusy(true)
+    try {
+      await api.post('/api/skills/install', { organizationId, sourceSkillId })
+      toast.success(`Installed ${name} into your library.`)
+      await load()
+    } catch (err) {
+      toast.error((err as Error).message)
+    } finally {
+      setBusy(false)
+    }
+  }
+
   const save = async () => {
     if (!form) return
     setBusy(true)
@@ -260,6 +292,8 @@ export function SkillsPage() {
                 onNewVersion={(v) => openForm(key, v, 'version')}
                 onEdit={(v) => openForm(key, v, 'edit')}
                 onFork={(v) => fork(key, v)}
+                onPublish={(v) => setListed(key, v, true)}
+                onUnpublish={(v) => setListed(key, v, false)}
               />
             ))}
             {groups.length === 0 && (
@@ -269,23 +303,38 @@ export function SkillsPage() {
         ) : (
           <div className="flex flex-col gap-4">
             <p className="text-sm text-muted-foreground">
-              Public skills shared by other organizations. One-click install lands in the next step.
+              Published skills shared by other organizations. Install a copy into your library — it lands private,
+              so you can edit or version it freely.
             </p>
-            {marketplace.map((s) => (
-              <Card key={`${s.organizationId}-${s.skillKey}-${s.version}`}>
+            {marketplace.map(({ skill: s, alreadyInLibrary }) => (
+              <Card key={s.id}>
                 <CardHeader className="pb-3">
                   <CardTitle className="flex items-center gap-2 text-base">
                     {s.name} <Badge variant="outline">{s.version}</Badge>
+                    <span className="font-mono text-xs text-muted-foreground">{s.skillKey}</span>
                   </CardTitle>
                   <CardDescription>{s.summary}</CardDescription>
                 </CardHeader>
-                <CardContent className="flex items-center gap-2">
+                <CardContent className="flex flex-wrap items-center gap-2">
                   {s.roles.map((r) => <Badge key={r} variant="secondary">{r}</Badge>)}
-                  <Button size="sm" variant="outline" disabled className="ml-auto">Install (soon)</Button>
+                  <span className="text-xs text-muted-foreground">
+                    {s.goldenTestCount} golden test{s.goldenTestCount === 1 ? '' : 's'}
+                  </span>
+                  {alreadyInLibrary ? (
+                    <Badge variant="secondary" className="ml-auto">In your library</Badge>
+                  ) : (
+                    <Button size="sm" disabled={busy} className="ml-auto" onClick={() => install(s.id, s.name)}>
+                      <Download data-icon="inline-start" /> Install
+                    </Button>
+                  )}
                 </CardContent>
               </Card>
             ))}
-            {marketplace.length === 0 && <p className="text-sm text-muted-foreground">Nothing published yet.</p>}
+            {marketplace.length === 0 && (
+              <p className="text-sm text-muted-foreground">
+                Nothing published yet. Publish one of your own skills to share it here.
+              </p>
+            )}
           </div>
         )}
       </div>
@@ -420,16 +469,22 @@ function SkillGroupCard({
   onNewVersion,
   onEdit,
   onFork,
+  onPublish,
+  onUnpublish,
 }: {
   versions: SkillSummary[]
   busy: boolean
   onNewVersion: (version: string) => void
   onEdit: (version: string) => void
   onFork: (version: string) => void
+  onPublish: (version: string) => void
+  onUnpublish: (version: string) => void
 }) {
   const [selected, setSelected] = useState(versions[0].version)
   const current = versions.find((v) => v.version === selected) ?? versions[0]
   const isBuiltin = current.origin === 'Builtin'
+  const isListed = current.visibility === 'Public'
+  const canPublish = !isBuiltin && current.status === 'Published'
 
   return (
     <Card>
@@ -456,6 +511,7 @@ function SkillGroupCard({
         )}
         {current.roles.map((r) => <Badge key={r} variant="secondary">{r}</Badge>)}
         <span className="text-xs text-muted-foreground">{current.goldenTestCount} golden test{current.goldenTestCount === 1 ? '' : 's'}</span>
+        {isListed && <Badge variant="default" className="gap-1"><Store className="size-3" /> Listed</Badge>}
 
         <div className="ml-auto flex items-center gap-2">
           {isBuiltin ? (
@@ -463,9 +519,20 @@ function SkillGroupCard({
               <GitFork data-icon="inline-start" /> Fork to my org
             </Button>
           ) : (
-            <Button size="sm" variant="outline" disabled={busy} onClick={() => onEdit(current.version)}>
-              <Pencil data-icon="inline-start" /> Edit
-            </Button>
+            <>
+              <Button size="sm" variant="outline" disabled={busy} onClick={() => onEdit(current.version)}>
+                <Pencil data-icon="inline-start" /> Edit
+              </Button>
+              {isListed ? (
+                <Button size="sm" variant="outline" disabled={busy} onClick={() => onUnpublish(current.version)}>
+                  Unlist
+                </Button>
+              ) : canPublish ? (
+                <Button size="sm" variant="outline" disabled={busy} onClick={() => onPublish(current.version)}>
+                  <Upload data-icon="inline-start" /> Publish
+                </Button>
+              ) : null}
+            </>
           )}
           <Button size="sm" disabled={busy} onClick={() => onNewVersion(current.version)}>
             <Plus data-icon="inline-start" /> New version
diff --git a/src/Modules/TeamUp.Modules.Skills/Domain/Skill.cs b/src/Modules/TeamUp.Modules.Skills/Domain/Skill.cs
index 4c38dbf..742bc3a 100644
--- a/src/Modules/TeamUp.Modules.Skills/Domain/Skill.cs
+++ b/src/Modules/TeamUp.Modules.Skills/Domain/Skill.cs
@@ -75,9 +75,12 @@ internal sealed class Skill : Entity
         GoldenTests = manifest.GoldenTests
             .Select(g => new GoldenExample { Input = g.Input, Expected = g.Expected })
             .ToList();
-        Visibility = ParseVisibility(manifest.Visibility);
-        MinTier = ParseTier(manifest.MinTier);
         Status = status;
+        // Invariant: only a published (golden-tested) skill may be Public. This holds on every
+        // (re)projection, so re-authoring a listed version without golden tests can't leave it
+        // Public+Draft — the marketplace/listing gate can never be decoupled from the eval gate.
+        Visibility = status == SkillStatus.Published ? ParseVisibility(manifest.Visibility) : SkillVisibility.PrivateToOrg;
+        MinTier = ParseTier(manifest.MinTier);
         Body = body;
         ContentHash = contentHash;
         SourceRepo = sourceRepo;
@@ -87,6 +90,13 @@ internal sealed class Skill : Entity
         UpdatedAtUtc = nowUtc;
     }
 
+    /// <summary>Lists/unlists this version on the marketplace (Public ⇔ PrivateToOrg).</summary>
+    public void SetVisibility(SkillVisibility visibility, DateTimeOffset nowUtc)
+    {
+        Visibility = visibility;
+        UpdatedAtUtc = nowUtc;
+    }
+
     private static string Normalize(string value) => value.Trim().Replace("-", string.Empty).Replace("_", string.Empty);
 
     private static ActionRisk ParseRisk(string value) => Normalize(value).ToLowerInvariant() switch
diff --git a/src/Modules/TeamUp.Modules.Skills/Endpoints/SkillsDtos.cs b/src/Modules/TeamUp.Modules.Skills/Endpoints/SkillsDtos.cs
index 7218e97..3de9b69 100644
--- a/src/Modules/TeamUp.Modules.Skills/Endpoints/SkillsDtos.cs
+++ b/src/Modules/TeamUp.Modules.Skills/Endpoints/SkillsDtos.cs
@@ -5,6 +5,7 @@ internal sealed record ActionDto(string Name, string Risk, string? Description =
 internal sealed record GoldenTestDto(string Input, string Expected);
 
 internal sealed record SkillSummary(
+    Guid Id,
     string SkillKey,
     string Name,
     string Version,
@@ -54,3 +55,12 @@ internal sealed record AuthorSkillRequest(
 
 /// <summary>Copy a builtin/other skill into an org as an editable Authored skill.</summary>
 internal sealed record ForkSkillRequest(Guid OrganizationId, string Version, string? Name);
+
+/// <summary>List/unlist one of an org's own (published) skill versions on the marketplace.</summary>
+internal sealed record PublishSkillRequest(Guid OrganizationId, string Version);
+
+/// <summary>Install a public marketplace skill (by its row id) into an org as an Installed copy.</summary>
+internal sealed record InstallSkillRequest(Guid OrganizationId, Guid SourceSkillId);
+
+/// <summary>A marketplace listing plus whether the requesting org already holds that skill key.</summary>
+internal sealed record MarketplaceEntry(SkillSummary Skill, bool AlreadyInLibrary);
diff --git a/src/Modules/TeamUp.Modules.Skills/Endpoints/SkillsEndpoints.cs b/src/Modules/TeamUp.Modules.Skills/Endpoints/SkillsEndpoints.cs
index 73d52da..18e2c7a 100644
--- a/src/Modules/TeamUp.Modules.Skills/Endpoints/SkillsEndpoints.cs
+++ b/src/Modules/TeamUp.Modules.Skills/Endpoints/SkillsEndpoints.cs
@@ -27,6 +27,9 @@ internal static class SkillsEndpoints
         group.MapGet("/{key}", GetSkill).RequireAuthorization();
         group.MapPost("/authored", AuthorSkill).RequireAuthorization();
         group.MapPost("/{key}/fork", ForkSkill).RequireAuthorization();
+        group.MapPost("/{key}/publish", PublishSkill).RequireAuthorization();
+        group.MapPost("/{key}/unpublish", UnpublishSkill).RequireAuthorization();
+        group.MapPost("/install", InstallSkill).RequireAuthorization();
         group.MapPost("/index", IndexSkill).RequireAuthorization();
         group.MapPost("/sync", Sync).RequireAuthorization();
         group.MapPost("/webhook/gitea", Webhook).AllowAnonymous();
@@ -102,14 +105,143 @@ internal static class SkillsEndpoints
 
     // Marketplace seam (read-only groundwork): publicly-shared, org-authored skills from any org.
     // Publishing controls and install-into-your-org land in the next step.
-    private static async Task<IResult> Marketplace(SkillsDbContext db, CancellationToken ct)
+    // The marketplace: published skills other orgs have listed publicly. Excludes your own skills
+    // and flags any whose key already exists in your library (installed or authored).
+    private static async Task<IResult> Marketplace(
+        Guid organizationId, IPermissionService permissions, SkillsDbContext db, CancellationToken ct)
     {
+        if (!permissions.Has(Capability.ViewBoard, ScopeRef.Org(organizationId)))
+        {
+            return Results.Forbid();
+        }
+
         var listed = await db.Skills
-            .Where(s => s.Origin == SkillOrigin.Authored && s.Visibility == SkillVisibility.Public)
+            .Where(s => s.Origin == SkillOrigin.Authored
+                && s.Visibility == SkillVisibility.Public
+                && s.Status == SkillStatus.Published
+                && s.OrganizationId != null
+                && s.OrganizationId != organizationId)
             .OrderBy(s => s.SkillKey)
             .ThenByDescending(s => s.Version)
             .ToListAsync(ct);
-        return Results.Ok(listed.Select(ToSummary).ToList());
+
+        // Flag by (key, version) — matching the install conflict rule — so a newer, not-yet-owned
+        // version of a key you already hold still shows as installable.
+        var owned = (await db.Skills
+            .Where(s => s.OrganizationId == organizationId)
+            .Select(s => new { s.SkillKey, s.Version })
+            .ToListAsync(ct))
+            .Select(s => (s.SkillKey, s.Version))
+            .ToHashSet();
+
+        return Results.Ok(listed
+            .Select(s => new MarketplaceEntry(ToSummary(s), owned.Contains((s.SkillKey, s.Version))))
+            .ToList());
+    }
+
+    private static async Task<IResult> PublishSkill(
+        string key, PublishSkillRequest request, ICurrentUser user, IPermissionService permissions,
+        IAuditLog audit, SkillsDbContext db, TimeProvider clock, CancellationToken ct)
+    {
+        if (!permissions.Has(Capability.ManageSkills, ScopeRef.Org(request.OrganizationId)))
+        {
+            return Results.Forbid();
+        }
+
+        var skill = await db.Skills.FirstOrDefaultAsync(
+            s => s.OrganizationId == request.OrganizationId && s.SkillKey == key && s.Version == request.Version, ct);
+        if (skill is null)
+        {
+            return Results.NotFound();
+        }
+
+        // Only golden-tested (published) skills may be listed — the marketplace inherits the eval gate.
+        if (skill.Status != SkillStatus.Published)
+        {
+            return Results.BadRequest("Only a published (golden-tested) skill can be listed on the marketplace.");
+        }
+
+        skill.SetVisibility(SkillVisibility.Public, clock.GetUtcNow());
+        await db.SaveChangesAsync(ct);
+        await audit.WriteAsync(
+            new AuditEvent("skill.published", "Skill", skill.Id, user.MemberId, $"{skill.SkillKey}@{skill.Version}"), ct);
+        return Results.Ok(ToDetail(skill));
+    }
+
+    private static async Task<IResult> UnpublishSkill(
+        string key, PublishSkillRequest request, ICurrentUser user, IPermissionService permissions,
+        IAuditLog audit, SkillsDbContext db, TimeProvider clock, CancellationToken ct)
+    {
+        if (!permissions.Has(Capability.ManageSkills, ScopeRef.Org(request.OrganizationId)))
+        {
+            return Results.Forbid();
+        }
+
+        var skill = await db.Skills.FirstOrDefaultAsync(
+            s => s.OrganizationId == request.OrganizationId && s.SkillKey == key && s.Version == request.Version, ct);
+        if (skill is null)
+        {
+            return Results.NotFound();
+        }
+
+        skill.SetVisibility(SkillVisibility.PrivateToOrg, clock.GetUtcNow());
+        await db.SaveChangesAsync(ct);
+        await audit.WriteAsync(
+            new AuditEvent("skill.unpublished", "Skill", skill.Id, user.MemberId, $"{skill.SkillKey}@{skill.Version}"), ct);
+        return Results.Ok(ToDetail(skill));
+    }
+
+    // Copy a publicly-listed skill into the caller's org as a private Installed copy.
+    private static async Task<IResult> InstallSkill(
+        InstallSkillRequest request, ICurrentUser user, IPermissionService permissions,
+        IAuditLog audit, SkillsDbContext db, SkillIndexer indexer, CancellationToken ct)
+    {
+        if (!permissions.Has(Capability.ManageSkills, ScopeRef.Org(request.OrganizationId)))
+        {
+            return Results.Forbid();
+        }
+
+        var source = await db.Skills.FirstOrDefaultAsync(s => s.Id == request.SourceSkillId, ct);
+        if (source is null)
+        {
+            return Results.NotFound();
+        }
+
+        if (source.Origin != SkillOrigin.Authored
+            || source.Visibility != SkillVisibility.Public
+            || source.Status != SkillStatus.Published)
+        {
+            return Results.BadRequest("That skill is not published to the marketplace.");
+        }
+
+        if (source.OrganizationId == request.OrganizationId)
+        {
+            return Results.BadRequest("That skill already belongs to your organization.");
+        }
+
+        if (await db.Skills.AnyAsync(
+            s => s.OrganizationId == request.OrganizationId && s.SkillKey == source.SkillKey && s.Version == source.Version, ct))
+        {
+            return Results.Conflict("This skill version is already in your library.");
+        }
+
+        var manifest = ToManifest(source);
+        manifest.Visibility = "private"; // an installed copy is private until the installer chooses to publish it
+        try
+        {
+            // insertOnly: the DB unique index is the source of truth, so a race with a concurrent
+            // install/author of the same (org, key, version) becomes a clean 409, never a clobber.
+            var skill = await indexer.IndexAsync(
+                manifest, source.Body, SkillOwnership.Installed(request.OrganizationId, user.MemberId),
+                insertOnly: true, cancellationToken: ct);
+            await audit.WriteAsync(
+                new AuditEvent("skill.installed", "Skill", skill.Id, user.MemberId, $"{skill.SkillKey}@{skill.Version}"), ct);
+            return Results.Ok(ToDetail(skill));
+        }
+        catch (DbUpdateException)
+        {
+            return Results.Conflict("This skill version is already in your library.");
+        }
     }
 
     private static async Task<IResult> GetSkill(
@@ -150,7 +282,7 @@ internal static class SkillsEndpoints
 
         var manifest = ToManifest(request);
         var skill = await indexer.IndexAsync(
-            manifest, request.Body.Trim(), SkillOwnership.Authored(request.OrganizationId, user.MemberId), ct);
+            manifest, request.Body.Trim(), SkillOwnership.Authored(request.OrganizationId, user.MemberId), cancellationToken: ct);
 
         await audit.WriteAsync(
             new AuditEvent("skill.authored", "Skill", skill.Id, user.MemberId, $"{skill.SkillKey}@{skill.Version}"), ct);
@@ -183,7 +315,7 @@ internal static class SkillsEndpoints
         }
 
         var skill = await indexer.IndexAsync(
-            manifest, source.Body, SkillOwnership.Authored(request.OrganizationId, user.MemberId), ct);
+            manifest, source.Body, SkillOwnership.Authored(request.OrganizationId, user.MemberId), cancellationToken: ct);
 
         await audit.WriteAsync(
             new AuditEvent("skill.forked", "Skill", skill.Id, user.MemberId, $"{skill.SkillKey}@{skill.Version}"), ct);
@@ -231,7 +363,8 @@ internal static class SkillsEndpoints
             .ToList(),
         Tools = request.Tools ?? [],
         Context = request.Context ?? [],
-        Visibility = string.IsNullOrWhiteSpace(request.Visibility) ? "public" : request.Visibility,
+        // Authored skills are private by default; listing on the marketplace is an explicit publish step.
+        Visibility = string.IsNullOrWhiteSpace(request.Visibility) ? "private" : request.Visibility,
         MinTier = string.IsNullOrWhiteSpace(request.MinTier) ? "free" : request.MinTier,
         GoldenTests = (request.GoldenTests ?? [])
             .Select(g => new GoldenExample { Input = g.Input, Expected = g.Expected })
@@ -258,6 +391,7 @@ internal static class SkillsEndpoints
     };
 
     private static SkillSummary ToSummary(Skill skill) => new(
+        skill.Id,
         skill.SkillKey,
         skill.Name,
         skill.Version,
diff --git a/src/Modules/TeamUp.Modules.Skills/Indexing/SkillIndexer.cs b/src/Modules/TeamUp.Modules.Skills/Indexing/SkillIndexer.cs
index a4ef163..ea358a8 100644
--- a/src/Modules/TeamUp.Modules.Skills/Indexing/SkillIndexer.cs
+++ b/src/Modules/TeamUp.Modules.Skills/Indexing/SkillIndexer.cs
@@ -34,19 +34,25 @@ internal sealed class SkillIndexer(SkillsDbContext db, ISkillEmbedder embedder,
     {
         var parsed = SkillMarkdownParser.Parse(content);
         var contentHash = Hash(content);
-        return IndexAsync(parsed.Manifest, parsed.Body, contentHash, SkillOwnership.Builtin, sourceRepo, sourcePath, sourceCommit, cancellationToken);
+        return IndexAsync(parsed.Manifest, parsed.Body, contentHash, SkillOwnership.Builtin, sourceRepo, sourcePath, sourceCommit, insertOnly: false, cancellationToken);
     }
 
-    /// <summary>Index a manifest authored/installed in-app — same pipeline, org-owned.</summary>
+    /// <summary>
+    /// Index a manifest authored/installed in-app — same pipeline, org-owned. When
+    /// <paramref name="insertOnly"/> is true the row must not already exist: it is always inserted
+    /// and a colliding (org, key, version) trips the unique index (DbUpdateException) rather than
+    /// silently overwriting — the install path uses this so a race can't clobber an existing skill.
+    /// </summary>
     public Task<Skill> IndexAsync(
         SkillManifest manifest,
         string body,
         SkillOwnership ownership,
+        bool insertOnly = false,
         CancellationToken cancellationToken = default)
     {
         // The content hash spans the structured manifest + body so re-authoring changes it.
         var canonical = $"{manifest.Id}\n{manifest.Version}\n{manifest.Summary}\n{string.Join(',', manifest.Roles)}\n{body}";
-        return IndexAsync(manifest, body, Hash(canonical), ownership, sourceRepo: null, sourcePath: null, sourceCommit: null, cancellationToken);
+        return IndexAsync(manifest, body, Hash(canonical), ownership, sourceRepo: null, sourcePath: null, sourceCommit: null, insertOnly, cancellationToken);
     }
 
     private async Task<Skill> IndexAsync(
@@ -57,6 +63,7 @@ internal sealed class SkillIndexer(SkillsDbContext db, ISkillEmbedder embedder,
         string? sourceRepo,
         string? sourcePath,
         string? sourceCommit,
+        bool insertOnly,
         CancellationToken cancellationToken)
     {
         var now = clock.GetUtcNow();
@@ -71,9 +78,11 @@ internal sealed class SkillIndexer(SkillsDbContext db, ISkillEmbedder embedder,
             ? SkillStatus.Published
             : SkillStatus.Draft;
 
-        var skill = await db.Skills.FirstOrDefaultAsync(
-            s => s.OrganizationId == ownership.OrganizationId && s.SkillKey == manifest.Id && s.Version == manifest.Version,
-            cancellationToken);
+        var skill = insertOnly
+            ? null
+            : await db.Skills.FirstOrDefaultAsync(
+                s => s.OrganizationId == ownership.OrganizationId && s.SkillKey == manifest.Id && s.Version == manifest.Version,
+                cancellationToken);
 
         var isNew = skill is null;
         skill ??= Skill.Create(manifest.Id, manifest.Version, ownership.OrganizationId, now);
diff --git a/tests/TeamUp.IntegrationTests/SkillMarketplaceTests.cs b/tests/TeamUp.IntegrationTests/SkillMarketplaceTests.cs
new file mode 100644
index 0000000..c317c03
--- /dev/null
+++ b/tests/TeamUp.IntegrationTests/SkillMarketplaceTests.cs
@@ -0,0 +1,195 @@
+using System.Net;
+using System.Net.Http.Headers;
+using System.Net.Http.Json;
+using Microsoft.Extensions.DependencyInjection;
+using TeamUp.Modules.Skills.Domain;
+using TeamUp.Modules.Skills.Indexing;
+using Xunit;
+
+namespace TeamUp.IntegrationTests;
+
+/// <summary>
+/// The skill marketplace, end to end: the publish gate (only golden-tested may list), own-org
+/// exclusion, another org's published skill listed and installed as a private copy, the duplicate
+/// conflict, and ManageSkills authorization. One flow per class — bootstrap is single-use.
+/// </summary>
+public sealed class SkillMarketplaceTests(PostgresFixture postgres) : IClassFixture<PostgresFixture>
+{
+    private sealed record BootstrapResponse(string Token, Guid MemberId, Guid OrganizationId);
+
+    private sealed record AuthResponse(string Token, Guid MemberId);
+
+    private sealed record InviteResponse(Guid InvitationId, string Token);
+
+    private sealed record ActionDto(string Name, string Risk, string? Description);
+
+    private sealed record GoldenTestDto(string Input, string Expected);
+
+    private sealed record SkillSummary(
+        Guid Id, string SkillKey, string Name, string Version, string? Summary, List<string> Roles,
+        string Visibility, string MinTier, string Status, string Origin, Guid? OrganizationId,
+        int GoldenTestCount, List<ActionDto> Actions);
+
+    private sealed record SkillDetail(
+        SkillSummary Skill, string? Inputs, string? Outputs, List<string> Tools,
+        List<string> Context, List<GoldenTestDto> GoldenTests, string Body);
+
+    private sealed record MarketplaceEntry(SkillSummary Skill, bool AlreadyInLibrary);
+
+    [Fact]
+    public async Task Publishes_lists_installs_with_gate_own_exclusion_and_authorization()
+    {
+        await using var factory = new TeamUpWebFactory(postgres.ConnectionString);
+        using var anon = factory.CreateClient();
+
+        var orgA = await PostOk<BootstrapResponse>(anon, "/api/identity/bootstrap", new
+        {
+            organizationName = "OrgA",
+            ownerEmail = "owner@alia.test",
+            ownerDisplayName = "Owner",
+            ownerPassword = "Passw0rd!",
+        });
+        using var client = Authed(factory, orgA.Token);
+
+        // Gate: a Draft (no golden test) cannot be listed on the marketplace.
+        await PostOk<SkillDetail>(client, "/api/skills/authored", Authored(orgA.OrganizationId, "draft-skill", goldenTested: false));
+        var cantPublish = await client.PostAsJsonAsync("/api/skills/draft-skill/publish",
+            new { organizationId = orgA.OrganizationId, version = "1.0.0" });
+        Assert.Equal(HttpStatusCode.BadRequest, cantPublish.StatusCode);
+
+        // A published skill lists fine; visibility flips to Public, but it never shows in its own org's marketplace.
+        await PostOk<SkillDetail>(client, "/api/skills/authored", Authored(orgA.OrganizationId, "prod-skill", goldenTested: true));
+        var published = await PostOk<SkillDetail>(client, "/api/skills/prod-skill/publish",
+            new { organizationId = orgA.OrganizationId, version = "1.0.0" });
+        Assert.Equal("Public", published.Skill.Visibility);
+
+        var ownMarket = await client.GetFromJsonAsync<List<MarketplaceEntry>>(
+            $"/api/skills/marketplace?organizationId={orgA.OrganizationId}");
+        Assert.DoesNotContain(ownMarket!, e => e.Skill.SkillKey == "prod-skill");
+
+        // You can't install your own skill.
+        var prod = await client.GetFromJsonAsync<List<SkillDetail>>(
+            $"/api/skills/prod-skill?organizationId={orgA.OrganizationId}");
+        var installOwn = await client.PostAsJsonAsync("/api/skills/install",
+            new { organizationId = orgA.OrganizationId, sourceSkillId = prod!.Single().Skill.Id });
+        Assert.Equal(HttpStatusCode.BadRequest, installOwn.StatusCode);
+
+        // Another org's published skill (no second-org onboarding yet — seed it via the indexer).
+        var orgB = Guid.NewGuid();
+        var sourceId = await SeedPublishedSkillAsync(factory, orgB, "research-brief", "Research Brief");
+
+        // Org A sees org B's skill on the marketplace, not yet in its library.
+        var market = await client.GetFromJsonAsync<List<MarketplaceEntry>>(
+            $"/api/skills/marketplace?organizationId={orgA.OrganizationId}");
+        var entry = Assert.Single(market!, e => e.Skill.SkillKey == "research-brief");
+        Assert.False(entry.AlreadyInLibrary);
+        Assert.Equal(sourceId, entry.Skill.Id);
+
+        // Installing lands a private, Installed copy in org A's namespace.
+        var installed = await PostOk<SkillDetail>(client, "/api/skills/install",
+            new { organizationId = orgA.OrganizationId, sourceSkillId = sourceId });
+        Assert.Equal("Installed", installed.Skill.Origin);
+        Assert.Equal(orgA.OrganizationId, installed.Skill.OrganizationId);
+        Assert.Equal("PrivateToOrg", installed.Skill.Visibility);
+        Assert.Equal("research-brief", installed.Skill.SkillKey);
+
+        // Now it's in the library (flagged), and re-installing the same version is a conflict.
+        var market2 = await client.GetFromJsonAsync<List<MarketplaceEntry>>(
+            $"/api/skills/marketplace?organizationId={orgA.OrganizationId}");
+        Assert.True(Assert.Single(market2!, e => e.Skill.SkillKey == "research-brief").AlreadyInLibrary);
+
+        var dup = await client.PostAsJsonAsync("/api/skills/install",
+            new { organizationId = orgA.OrganizationId, sourceSkillId = sourceId });
+        Assert.Equal(HttpStatusCode.Conflict, dup.StatusCode);
+
+        // A newer version of an already-installed key stays installable — the flag is per (key, version).
+        var sourceV2 = await SeedPublishedSkillAsync(factory, orgB, "research-brief", "Research Brief", "2.0.0");
+        var market3 = await client.GetFromJsonAsync<List<MarketplaceEntry>>(
+            $"/api/skills/marketplace?organizationId={orgA.OrganizationId}");
+        Assert.False(Assert.Single(market3!, e => e.Skill.Id == sourceV2).AlreadyInLibrary);
+        Assert.True(Assert.Single(market3!, e => e.Skill.SkillKey == "research-brief" && e.Skill.Version == "1.0.0").AlreadyInLibrary);
+
+        // Invariant: re-authoring a listed version without golden tests cannot leave it Public.
+        await PostOk<SkillDetail>(client, "/api/skills/authored", Authored(orgA.OrganizationId, "regate-skill", goldenTested: true));
+        await PostOk<SkillDetail>(client, "/api/skills/regate-skill/publish",
+            new { organizationId = orgA.OrganizationId, version = "1.0.0" });
+        var degated = await PostOk<SkillDetail>(client, "/api/skills/authored",
+            Authored(orgA.OrganizationId, "regate-skill", goldenTested: false, visibility: "public"));
+        Assert.Equal("Draft", degated.Skill.Status);
+        Assert.Equal("PrivateToOrg", degated.Skill.Visibility);
+
+        // A plain Member cannot publish/unpublish (ManageSkills).
+        var invite = await PostOk<InviteResponse>(client, "/api/identity/invitations", new
+        {
+            email = "member@alia.test",
+            scopeType = "Organization",
+            scopeId = orgA.OrganizationId,
+            role = "Member",
+            organizationId = orgA.OrganizationId,
+        });
+        var member = await PostOk<AuthResponse>(anon, "/api/identity/invitations/accept",
+            new { token = invite.Token, displayName = "Member", password = "Passw0rd!" });
+        using var memberClient = Authed(factory, member.Token);
+        var forbidden = await memberClient.PostAsJsonAsync("/api/skills/prod-skill/unpublish",
+            new { organizationId = orgA.OrganizationId, version = "1.0.0" });
+        Assert.Equal(HttpStatusCode.Forbidden, forbidden.StatusCode);
+    }
+
+    private static object Authored(Guid organizationId, string key, bool goldenTested, string visibility = "private") => new
+    {
+        organizationId,
+        skillKey = key,
+        name = key,
+        version = "1.0.0",
+        summary = "x",
+        roles = new[] { "engineer" },
+        inputs = (string?)null,
+        outputs = (string?)null,
+        actions = Array.Empty<ActionDto>(),
+        tools = Array.Empty<string>(),
+        context = Array.Empty<string>(),
+        visibility,
+        minTier = "free",
+        body = "Do the thing.",
+        goldenTests = goldenTested
+            ? new[] { new GoldenTestDto("in", "out") }
+            : Array.Empty<GoldenTestDto>(),
+    };
+
+    // No public second-org onboarding yet, so seed the "other org's" published skill directly through
+    // the same indexer the authoring endpoint uses (InternalsVisibleTo grants the test access).
+    private static async Task<Guid> SeedPublishedSkillAsync(
+        TeamUpWebFactory factory, Guid orgId, string key, string name, string version = "1.0.0")
+    {
+        using var scope = factory.Services.CreateScope();
+        var indexer = scope.ServiceProvider.GetRequiredService<SkillIndexer>();
+        var manifest = new SkillManifest
+        {
+            Id = key,
+            Name = name,
+            Version = version,
+            Summary = "A shared, published skill.",
+            Roles = ["analyst"],
+            Visibility = "public",
+            GoldenTests = [new GoldenExample { Input = "a topic", Expected = "a brief" }],
+        };
+        var skill = await indexer.IndexAsync(manifest, "Write a research brief.", SkillOwnership.Authored(orgId, Guid.NewGuid()));
+        return skill.Id;
+    }
+
+    private static HttpClient Authed(TeamUpWebFactory factory, string token)
+    {
+        var client = factory.CreateClient();
+        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
+        return client;
+    }
+
+    private static async Task<T> PostOk<T>(HttpClient client, string url, object body)
+    {
+        var response = await client.PostAsJsonAsync(url, body);
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        var value = await response.Content.ReadFromJsonAsync<T>();
+        Assert.NotNull(value);
+        return value!;
+    }
+}