diff --git a/Cargo.lock b/Cargo.lock
index 794a9fd3..1c9d9466 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -43,6 +43,7 @@ dependencies = [
  "rayon",
  "rfd",
  "rustc-hash 2.1.3",
+ "semver",
  "serde",
  "serde_json",
  "truck-meshalgo",
@@ -1867,6 +1868,15 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "getopts"
+version = "0.2.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cfe4fbac503b8d1f88e6676011885f34b7174f46e59956bba534ba83abded4df"
+dependencies = [
+ "unicode-width",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.2.17"
@@ -2376,6 +2386,7 @@ dependencies = [
  "iced_renderer",
  "log",
  "num-traits",
+ "pulldown-cmark",
  "rustc-hash 2.1.3",
  "thiserror 2.0.18",
  "unicode-segmentation",
@@ -4136,6 +4147,25 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "pulldown-cmark"
+version = "0.12.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f86ba2052aebccc42cbbb3ed234b8b13ce76f75c3551a303cb2bcffcff12bb14"
+dependencies = [
+ "bitflags 2.13.1",
+ "getopts",
+ "memchr 2.8.3",
+ "pulldown-cmark-escape",
+ "unicase",
+]
+
+[[package]]
+name = "pulldown-cmark-escape"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "007d8adb5ddab6f8e3f491ac63566a7d5002cc7ed73901f72057943fa71ae1ae"
+
 [[package]]
 name = "pulp"
 version = "0.22.3"
@@ -5695,6 +5725,12 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "unicase"
+version = "2.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dbc4bc3a9f746d862c45cb89d705aa10f187bb96c76001afab07a0d35ce60142"
+
 [[package]]
 name = "unicode-bidi"
 version = "0.3.18"
diff --git a/Cargo.toml b/Cargo.toml
index 8545571b..dcaad6fa 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -35,6 +35,7 @@ solid3d = ["dep:truck-meshalgo", "dep:truck-shapeops", "dep:lzma-sys"]
 # and the consolidated user config (settings.json) via serde-derived structs.
 serde_json = "1"
 serde = { version = "1", features = ["derive"] }
+semver = "1"
 # Stable, dependency-free add-on contract (manifest + ribbon/CadModule types).
 # Plugin authors target this crate's semver, not OpenCADStudio internals.
 # The `host` feature (out-of-process plugin runtime: interprocess, libloading,
@@ -47,7 +48,7 @@ serde = { version = "1", features = ["derive"] }
 # Forcing the `static` feature builds liblzma from the bundled source, making
 # the binary self-contained on every platform.
 lzma-sys = { version = "0.1", features = ["static"], optional = true }
-iced = { version = "0.14", features = ["image", "svg", "advanced", "canvas", "smol"] }
+iced = { version = "0.14", features = ["image", "svg", "advanced", "canvas", "smol", "markdown"] }
 iced_aw = { version = "0.14.1", features = ["menu"] }
 bytemuck = { version = "1.25", features = ["derive"] }
 glam = { version = "0.33", features = ["bytemuck"] }
diff --git a/docs/plugin-template/plugin.toml b/docs/plugin-template/plugin.toml
index 6153aeaa..f2718db5 100644
--- a/docs/plugin-template/plugin.toml
+++ b/docs/plugin-template/plugin.toml
@@ -5,9 +5,10 @@ version = "0.1.0"
 description = "Short description of what this add-on does"
 author = "Your Name"
 license = "GPL-3.0-only"
+repository = "your-account/your-plugin-repo"
 
 [opencad]
 api_version = 3
 ribbon_order = 60
 command_prefixes = ["MP_"]
-xdata_apps = ["MYPLUGIN_RECORD"]
\ No newline at end of file
+xdata_apps = ["MYPLUGIN_RECORD"]
diff --git a/src/app/mod.rs b/src/app/mod.rs
index 96b0a68f..5d1aa6b0 100644
--- a/src/app/mod.rs
+++ b/src/app/mod.rs
@@ -528,10 +528,19 @@ pub(super) struct OpenCADStudio {
     plugin_repos: Vec<String>,
     /// Add-repository text field in the Plugin Manager.
     plugin_repo_input: String,
+    /// Live filter for installed and available plugin cards.
+    plugin_search_input: String,
     /// Installable release tags fetched per linked repo (for the dropdown).
     repo_release_tags: rustc_hash::FxHashMap<String, Vec<String>>,
     /// The release tag currently selected per linked repo.
     repo_selected_tag: rustc_hash::FxHashMap<String, String>,
+    /// Repository currently shown in the Plugin Manager detail pane.
+    selected_plugin_repo: Option<String>,
+    /// Parsed GitHub README content or the last fetch error, cached per repo.
+    plugin_readmes:
+        rustc_hash::FxHashMap<String, Result<iced::widget::markdown::Content, String>>,
+    /// README requests in flight, used to render a deterministic loading state.
+    plugin_readme_loading: rustc_hash::FxHashSet<String>,
     /// Last marketplace status / error line shown in the Plugin Manager.
     marketplace_status: String,
     /// PDSIZE text buffer for the Point Style (DDPTYPE) dialog.
@@ -2059,6 +2068,8 @@ pub enum Message {
     // ── Plugin marketplace (install from a linked repo's releases) ─────────
     /// Edit the add-repository text field.
     PluginRepoInput(String),
+    /// Filter installed and available plugin cards.
+    PluginSearchInput(String),
     /// Link the repository currently in the text field.
     PluginRepoAdd,
     /// Unlink a repository.
@@ -2079,8 +2090,14 @@ pub enum Message {
     PluginReleasesFetched(String, Result<Vec<String>, String>),
     /// Choose a release tag for a repo (`repo`, `tag`).
     PluginReleaseSelect(String, String),
+    /// Select a plugin source and show its GitHub README in the detail pane.
+    PluginReadmeSelect(String),
+    /// A GitHub README fetch finished (`repo`, Markdown or error).
+    PluginReadmeFetched(String, Result<String, String>),
     /// Install the selected release of `owner/repo`.
     PluginInstall(String),
+    /// Install a specific newer release from an installed plugin card.
+    PluginUpdate(String, String),
     /// Result of an install: the plugin id, or an error message.
     PluginInstalled(Result<String, String>),
     /// Delete an installed plugin's folder (effective next restart).
@@ -2594,8 +2611,12 @@ impl OpenCADStudio {
             plugin_registry: Vec::new(),
             plugin_repos: Vec::new(),
             plugin_repo_input: String::new(),
+            plugin_search_input: String::new(),
             repo_release_tags: rustc_hash::FxHashMap::default(),
             repo_selected_tag: rustc_hash::FxHashMap::default(),
+            selected_plugin_repo: None,
+            plugin_readmes: rustc_hash::FxHashMap::default(),
+            plugin_readme_loading: rustc_hash::FxHashSet::default(),
             marketplace_status: String::new(),
             point_size_buf: String::new(),
             point_size_relative: true,
diff --git a/src/app/update/file.rs b/src/app/update/file.rs
index 87f67168..6d96b31a 100644
--- a/src/app/update/file.rs
+++ b/src/app/update/file.rs
@@ -295,6 +295,21 @@ impl OpenCADStudio {
         Task::none()
     }
 
+    /// Background task: fetch a repository README from its default branch.
+    #[cfg(not(target_arch = "wasm32"))]
+    pub(in crate::app) fn fetch_plugin_readme_task(&self, repo: String) -> Task<Message> {
+        let label = repo.clone();
+        Task::perform(
+            async move { crate::plugin::marketplace::fetch_readme(&repo) },
+            move |result| Message::PluginReadmeFetched(label, result),
+        )
+    }
+
+    #[cfg(target_arch = "wasm32")]
+    pub(in crate::app) fn fetch_plugin_readme_task(&self, _repo: String) -> Task<Message> {
+        Task::none()
+    }
+
     /// Background task: download and install the `tag` release of `owner/repo`.
     #[cfg(not(target_arch = "wasm32"))]
     pub(in crate::app) fn install_task(&self, repo: String, tag: String) -> Task<Message> {
@@ -305,7 +320,7 @@ impl OpenCADStudio {
                     .into_iter()
                     .find(|r| r.tag == tag)
                     .ok_or_else(|| format!("release {tag} not found"))?;
-                crate::plugin::marketplace::install(&rel)
+                crate::plugin::marketplace::install(&rel, &repo)
             },
             Message::PluginInstalled,
         )
diff --git a/src/app/update/mod.rs b/src/app/update/mod.rs
index a49f7f1c..eeecf083 100644
--- a/src/app/update/mod.rs
+++ b/src/app/update/mod.rs
@@ -3951,17 +3951,42 @@ impl OpenCADStudio {
                 // Refresh the on-disk external-plugin list each time the manager
                 // opens so newly dropped-in packages show up.
                 self.external_plugins = crate::plugin::external::discover();
+                self.marketplace_status.clear();
                 self.active_modal = Some(super::ModalKind::PluginManager);
                 // Fetch the curated registry and release lists for linked repos.
                 #[cfg(not(target_arch = "wasm32"))]
                 {
                     let mut tasks = vec![self.fetch_registry_task()];
+                    let release_repos: rustc_hash::FxHashSet<String> = self
+                        .plugin_repos
+                        .iter()
+                        .cloned()
+                        .chain(
+                            self.external_plugins
+                                .iter()
+                                .filter_map(|plugin| plugin.repository.clone()),
+                        )
+                        .collect();
                     tasks.extend(
-                        self.plugin_repos
-                            .clone()
+                        release_repos
                             .into_iter()
                             .map(|r| self.fetch_releases_task(r)),
                     );
+                    if self.selected_plugin_repo.is_none() {
+                        self.selected_plugin_repo = self
+                            .external_plugins
+                            .iter()
+                            .find_map(|plugin| plugin.repository.clone())
+                            .or_else(|| self.plugin_registry.first().map(|entry| entry.repo.clone()))
+                            .or_else(|| self.plugin_repos.first().cloned());
+                    }
+                    if let Some(repo) = self.selected_plugin_repo.clone() {
+                        if !self.plugin_readmes.contains_key(&repo)
+                            && self.plugin_readme_loading.insert(repo.clone())
+                        {
+                            tasks.push(self.fetch_plugin_readme_task(repo));
+                        }
+                    }
                     return Task::batch(tasks);
                 }
                 #[cfg(target_arch = "wasm32")]
@@ -3985,26 +4010,66 @@ impl OpenCADStudio {
                 self.plugin_repo_input = s;
                 Task::none()
             }
+            Message::PluginSearchInput(s) => {
+                self.plugin_search_input = s;
+                Task::none()
+            }
             Message::PluginRepoAdd => {
-                let repo = self
-                    .plugin_repo_input
-                    .trim()
-                    .trim_start_matches("https://github.com/")
-                    .trim_end_matches('/')
-                    .to_string();
-                if repo.is_empty() || self.plugin_repos.contains(&repo) {
+                let Some(repo) =
+                    crate::plugin::external::normalize_repository(&self.plugin_repo_input)
+                else {
+                    self.marketplace_status =
+                        "Enter a GitHub URL or repository in owner/repo format.".to_string();
+                    return Task::none();
+                };
+                if self.plugin_repos.contains(&repo)
+                    || self.plugin_registry.iter().any(|entry| entry.repo == repo)
+                {
+                    self.marketplace_status = format!("{repo} is already in the catalog.");
+                    self.selected_plugin_repo = Some(repo.clone());
+                    if !self.plugin_readmes.contains_key(&repo)
+                        && self.plugin_readme_loading.insert(repo.clone())
+                    {
+                        return self.fetch_plugin_readme_task(repo);
+                    }
+                    return Task::none();
+                }
+                if self
+                    .external_plugins
+                    .iter()
+                    .any(|plugin| plugin.repository.as_deref() == Some(repo.as_str()))
+                {
+                    self.marketplace_status = format!("{repo} is already installed.");
+                    self.selected_plugin_repo = Some(repo.clone());
+                    if !self.plugin_readmes.contains_key(&repo)
+                        && self.plugin_readme_loading.insert(repo.clone())
+                    {
+                        return self.fetch_plugin_readme_task(repo);
+                    }
                     return Task::none();
                 }
                 self.plugin_repos.push(repo.clone());
                 self.plugin_repo_input.clear();
                 self.persist_settings_if_changed();
                 self.marketplace_status = format!("Fetching releases for {repo}…");
-                self.fetch_releases_task(repo)
+                self.selected_plugin_repo = Some(repo.clone());
+                self.plugin_readmes.remove(&repo);
+                self.plugin_readme_loading.insert(repo.clone());
+                Task::batch(vec![
+                    self.fetch_releases_task(repo.clone()),
+                    self.fetch_plugin_readme_task(repo),
+                ])
             }
             Message::PluginRepoRemove(repo) => {
                 self.plugin_repos.retain(|r| r != &repo);
                 self.repo_release_tags.remove(&repo);
                 self.repo_selected_tag.remove(&repo);
+                if self.selected_plugin_repo.as_deref() == Some(repo.as_str())
+                    && !self.plugin_registry.iter().any(|entry| entry.repo == repo)
+                {
+                    self.selected_plugin_repo =
+                        self.plugin_registry.first().map(|entry| entry.repo.clone());
+                }
                 self.persist_settings_if_changed();
                 Task::none()
             }
@@ -4012,11 +4077,32 @@ impl OpenCADStudio {
                 // Fetch releases for every curated repo so the dropdowns fill in.
                 #[cfg(not(target_arch = "wasm32"))]
                 {
-                    let tasks: Vec<_> = entries
+                    if self.selected_plugin_repo.is_none() {
+                        self.selected_plugin_repo = self
+                            .external_plugins
+                            .iter()
+                            .find_map(|plugin| {
+                                plugin.repository.clone().or_else(|| {
+                                    entries
+                                        .iter()
+                                        .find(|entry| entry.name.eq_ignore_ascii_case(&plugin.name))
+                                        .map(|entry| entry.repo.clone())
+                                })
+                            })
+                            .or_else(|| entries.first().map(|entry| entry.repo.clone()));
+                    }
+                    let mut tasks: Vec<_> = entries
                         .iter()
                         .map(|e| self.fetch_releases_task(e.repo.clone()))
                         .collect();
                     self.plugin_registry = entries;
+                    if let Some(repo) = self.selected_plugin_repo.clone() {
+                        if !self.plugin_readmes.contains_key(&repo)
+                            && self.plugin_readme_loading.insert(repo.clone())
+                        {
+                            tasks.push(self.fetch_plugin_readme_task(repo));
+                        }
+                    }
                     return Task::batch(tasks);
                 }
                 #[cfg(target_arch = "wasm32")]
@@ -4073,7 +4159,10 @@ impl OpenCADStudio {
                         .entry(repo.clone())
                         .or_insert_with(|| first.clone());
                 }
-                self.marketplace_status = format!("{repo}: {} installable release(s)", tags.len());
+                if self.marketplace_status == format!("Fetching releases for {repo}…") {
+                    self.marketplace_status =
+                        format!("Repository added. {} installable release(s) found.", tags.len());
+                }
                 self.repo_release_tags.insert(repo, tags);
                 Task::none()
             }
@@ -4085,6 +4174,27 @@ impl OpenCADStudio {
                 self.repo_selected_tag.insert(repo, tag);
                 Task::none()
             }
+            Message::PluginReadmeSelect(repo) => {
+                self.selected_plugin_repo = Some(repo.clone());
+                if self.plugin_readme_loading.contains(&repo) {
+                    return Task::none();
+                }
+                if matches!(self.plugin_readmes.get(&repo), Some(Ok(_))) {
+                    return Task::none();
+                }
+                // A second click on an error state acts as retry.
+                self.plugin_readmes.remove(&repo);
+                self.plugin_readme_loading.insert(repo.clone());
+                self.fetch_plugin_readme_task(repo)
+            }
+            Message::PluginReadmeFetched(repo, result) => {
+                self.plugin_readme_loading.remove(&repo);
+                self.plugin_readmes.insert(
+                    repo,
+                    result.map(|source| iced::widget::markdown::Content::parse(&source)),
+                );
+                Task::none()
+            }
             Message::PluginInstall(repo) => {
                 let Some(tag) = self.repo_selected_tag.get(&repo).cloned() else {
                     return Task::none();
@@ -4092,6 +4202,10 @@ impl OpenCADStudio {
                 self.marketplace_status = format!("Installing {repo} {tag}…");
                 self.install_task(repo, tag)
             }
+            Message::PluginUpdate(repo, tag) => {
+                self.marketplace_status = format!("Updating {repo} to {tag}…");
+                self.install_task(repo, tag)
+            }
             Message::PluginInstalled(Ok(id)) => {
                 self.marketplace_status = format!("Installed '{id}'. Restart to load it.");
                 #[cfg(not(target_arch = "wasm32"))]
diff --git a/src/app/view/mod.rs b/src/app/view/mod.rs
index 6c0572d4..085f294e 100644
--- a/src/app/view/mod.rs
+++ b/src/app/view/mod.rs
@@ -1537,7 +1537,7 @@ impl OpenCADStudio {
             About => (440, 360),
             Shortcuts => (720, 520),
             Options => (480, 190),
-            PluginManager => (520, 460),
+            PluginManager => (940, 600),
             UpdateNotice => (560, 460),
             Layers => (900, 360),
             Plot => (760, 540),
diff --git a/src/app/view/modal.rs b/src/app/view/modal.rs
index 9e4f6b04..60ab761b 100644
--- a/src/app/view/modal.rs
+++ b/src/app/view/modal.rs
@@ -79,14 +79,19 @@ impl OpenCADStudio {
                     crate::ui::window::plugin_manager::MarketView {
                         registry: &self.plugin_registry,
                         input: &self.plugin_repo_input,
+                        search: &self.plugin_search_input,
                         repos: &self.plugin_repos,
                         release_tags: &self.repo_release_tags,
                         selected_tag: &self.repo_selected_tag,
+                        selected_repo: self.selected_plugin_repo.as_deref(),
+                        readmes: &self.plugin_readmes,
+                        readme_loading: &self.plugin_readme_loading,
                         status: &self.marketplace_status,
                     },
+                    &self.active_theme,
                 ),
-                520,
-                460,
+                940,
+                600,
             ),
             super::super::ModalKind::UpdateNotice => {
                 let latest = self.update_notice_version.as_deref().unwrap_or("?");
diff --git a/src/plugin/external.rs b/src/plugin/external.rs
index 245c8891..4e4e3600 100644
--- a/src/plugin/external.rs
+++ b/src/plugin/external.rs
@@ -30,6 +30,10 @@ pub struct ExternalPlugin {
     pub name: String,
     pub version: String,
     pub description: String,
+    /// GitHub source in `owner/repo` form. New marketplace installs persist
+    /// this beside the manifest so their README remains discoverable even when
+    /// an older `plugin.toml` does not declare `repository`.
+    pub repository: Option<String>,
     pub api_version: u32,
     pub ribbon_order: i32,
     pub command_prefixes: Vec<String>,
@@ -125,6 +129,11 @@ pub fn discover() -> Vec<ExternalPlugin> {
             continue;
         };
         if let Some(mut p) = parse_plugin_toml(&text) {
+            if p.repository.is_none() {
+                p.repository = std::fs::read_to_string(dir.join(".source_repo"))
+                    .ok()
+                    .and_then(|repo| normalize_repository(&repo));
+            }
             p.lib_present = lib_present_in(&dir);
             p.dir = dir;
             found.push(p);
@@ -156,6 +165,7 @@ pub(crate) fn parse_plugin_toml(text: &str) -> Option<ExternalPlugin> {
     let mut name = String::new();
     let mut version = String::new();
     let mut description = String::new();
+    let mut repository = None;
     let mut api_version: u32 = 0;
     let mut ribbon_order: i32 = 0;
     let mut command_prefixes: Vec<String> = Vec::new();
@@ -175,6 +185,7 @@ pub(crate) fn parse_plugin_toml(text: &str) -> Option<ExternalPlugin> {
             "name" => name = unquote(value),
             "version" => version = unquote(value),
             "description" => description = unquote(value),
+            "repository" => repository = normalize_repository(&unquote(value)),
             "api_version" => api_version = value.parse().unwrap_or(0),
             "ribbon_order" => ribbon_order = value.parse().unwrap_or(0),
             "command_prefixes" => command_prefixes = parse_string_array(value),
@@ -187,6 +198,7 @@ pub(crate) fn parse_plugin_toml(text: &str) -> Option<ExternalPlugin> {
         name,
         version,
         description,
+        repository,
         api_version,
         ribbon_order,
         command_prefixes,
@@ -195,6 +207,26 @@ pub(crate) fn parse_plugin_toml(text: &str) -> Option<ExternalPlugin> {
     })
 }
 
+/// Convert a plugin source URL or shorthand to the marketplace's canonical
+/// `owner/repo` form.
+pub(crate) fn normalize_repository(value: &str) -> Option<String> {
+    let repo = value
+        .trim()
+        .trim_start_matches("https://github.com/")
+        .trim_start_matches("http://github.com/")
+        .trim_end_matches('/')
+        .trim_end_matches(".git");
+    let mut parts = repo.split('/');
+    let (Some(owner), Some(name), None) = (parts.next(), parts.next(), parts.next()) else {
+        return None;
+    };
+    if owner.is_empty() || name.is_empty() {
+        None
+    } else {
+        Some(format!("{owner}/{name}"))
+    }
+}
+
 /// Strip surrounding single or double quotes from a TOML scalar.
 fn unquote(s: &str) -> String {
     let s = s.trim();
@@ -321,6 +353,7 @@ id = "opencad.my_plugin"
 name = "My Plugin"
 version = "0.1.0"
 description = "Template plugin"
+repository = "https://github.com/example/opencad-my-plugin.git"
 
 [opencad]
 api_version = 2
@@ -330,6 +363,7 @@ xdata_apps = ["MYPLUGIN_RECORD"]
 "#;
         let p = parse_plugin_toml(toml).expect("parsed");
         assert_eq!(p.api_version, 2);
+        assert_eq!(p.repository.as_deref(), Some("example/opencad-my-plugin"));
         assert!(p.command_prefixes.contains(&"MP_".to_string()));
         assert!(p.api_compatible(), "API v2 plugins must run on API v3 host");
     }
diff --git a/src/plugin/marketplace.rs b/src/plugin/marketplace.rs
index 462cf25d..86c882d7 100644
--- a/src/plugin/marketplace.rs
+++ b/src/plugin/marketplace.rs
@@ -148,6 +148,20 @@ pub fn fetch_releases(repo: &str) -> Result<Vec<Release>, String> {
     Ok(out)
 }
 
+/// Fetch the repository README from its default branch as raw Markdown.
+pub fn fetch_readme(repo: &str) -> Result<String, String> {
+    let url = format!("https://api.github.com/repos/{repo}/readme");
+    agent()
+        .get(&url)
+        .header("User-Agent", UA)
+        .header("Accept", "application/vnd.github.raw+json")
+        .call()
+        .map_err(|e| e.to_string())?
+        .body_mut()
+        .read_to_string()
+        .map_err(|e| e.to_string())
+}
+
 fn download_string(url: &str) -> Result<String, String> {
     agent()
         .get(url)
@@ -176,7 +190,7 @@ fn download_bytes(url: &str) -> Result<Vec<u8>, String> {
 /// Download and install a release's package into the plugins folder. Verifies
 /// the API version from the package's `plugin.toml` first. Returns the plugin
 /// id on success.
-pub fn install(release: &Release) -> Result<String, String> {
+pub fn install(release: &Release, repository: &str) -> Result<String, String> {
     let lib = release.lib_asset().ok_or("no library for this platform")?;
     let toml = release.toml_asset().ok_or("release has no plugin.toml")?;
 
@@ -199,6 +213,8 @@ pub fn install(release: &Release) -> Result<String, String> {
     let bytes = download_bytes(&lib.url)?;
     replace_library(&dir, &lib.name, external_lib_ext(), &bytes)?;
     std::fs::write(dir.join("plugin.toml"), toml_text).map_err(|e| e.to_string())?;
+    std::fs::write(dir.join(".source_repo"), format!("{repository}\n"))
+        .map_err(|e| e.to_string())?;
     Ok(manifest.id)
 }
 
diff --git a/src/ui/window/plugin_manager.rs b/src/ui/window/plugin_manager.rs
index 3f1b903e..efc4921b 100644
--- a/src/ui/window/plugin_manager.rs
+++ b/src/ui/window/plugin_manager.rs
@@ -6,17 +6,27 @@
 
 use crate::app::Message;
 use crate::plugin::external::{ExternalPlugin, RegistryEntry};
-use iced::widget::{button, column, container, pick_list, row, scrollable, text, text_input, Space};
-use iced::{Background, Border, Element, Fill, Theme};
+use iced::widget::{
+    button, column, container, markdown, pick_list, row, rule, scrollable, text, text_input, Space,
+};
+use iced::{Background, Border, Element, Fill, Length, Theme};
 use rustc_hash::{FxHashMap, FxHashSet};
 
+/// Empty lane kept at the right edge of scroll content so the vertical
+/// scrollbar never covers card controls.
+const SCROLLBAR_GUTTER: f32 = 16.0;
+
 /// Marketplace state passed to the Plugin Manager view.
 pub struct MarketView<'a> {
     pub registry: &'a [RegistryEntry],
     pub input: &'a str,
+    pub search: &'a str,
     pub repos: &'a [String],
     pub release_tags: &'a FxHashMap<String, Vec<String>>,
     pub selected_tag: &'a FxHashMap<String, String>,
+    pub selected_repo: Option<&'a str>,
+    pub readmes: &'a FxHashMap<String, Result<markdown::Content, String>>,
+    pub readme_loading: &'a FxHashSet<String>,
     pub status: &'a str,
 }
 
@@ -104,7 +114,96 @@ fn status_badge<'a>(label: &str, kind: StatusKind) -> Element<'a, Message> {
         .into()
 }
 
-fn external_card<'a>(p: &ExternalPlugin, loaded: bool, disabled: bool) -> Element<'a, Message> {
+fn card_style(theme: &Theme, selected: bool) -> container::Style {
+    let palette = theme.extended_palette();
+    container::Style {
+        background: selected
+            .then(|| Background::Color(palette.primary.weak.color.scale_alpha(0.18))),
+        border: Border {
+            color: if selected {
+                palette.primary.base.color
+            } else {
+                palette.background.strong.color
+            },
+            width: if selected { 1.5 } else { 1.0 },
+            radius: 6.0.into(),
+        },
+        ..Default::default()
+    }
+}
+
+fn repository_for_external(
+    plugin: &ExternalPlugin,
+    registry: &[RegistryEntry],
+) -> Option<String> {
+    plugin.repository.clone().or_else(|| {
+        registry
+            .iter()
+            .find(|entry| entry.name.eq_ignore_ascii_case(&plugin.name))
+            .map(|entry| entry.repo.clone())
+    })
+}
+
+fn matches_search(query: &str, values: &[&str]) -> bool {
+    let query = query.trim().to_lowercase();
+    query.is_empty()
+        || values
+            .iter()
+            .any(|value| value.to_lowercase().contains(&query))
+}
+
+fn external_matches_search(plugin: &ExternalPlugin, repository: Option<&str>, query: &str) -> bool {
+    matches_search(
+        query,
+        &[
+            &plugin.name,
+            &plugin.id,
+            &plugin.description,
+            repository.unwrap_or_default(),
+        ],
+    ) || plugin
+        .command_prefixes
+        .iter()
+        .any(|command| matches_search(query, &[command]))
+}
+
+fn repository_is_installed(
+    repository: &str,
+    registry_name: Option<&str>,
+    externals: &[ExternalPlugin],
+) -> bool {
+    externals.iter().any(|plugin| {
+        plugin.repository.as_deref() == Some(repository)
+            || registry_name
+                .is_some_and(|name| plugin.name.eq_ignore_ascii_case(name))
+    })
+}
+
+fn trim_version_prefix(value: &str) -> &str {
+    value.trim_start_matches(|c| c == 'v' || c == 'V')
+}
+
+fn newest_update(installed: &str, tags: &[String]) -> Option<String> {
+    let installed = semver::Version::parse(trim_version_prefix(installed)).ok()?;
+    tags.iter()
+        .filter_map(|tag| {
+            semver::Version::parse(trim_version_prefix(tag))
+                .ok()
+                .map(|version| (version, tag))
+        })
+        .filter(|(version, _)| version > &installed)
+        .max_by(|(left, _), (right, _)| left.cmp(right))
+        .map(|(_, tag)| tag.clone())
+}
+
+fn external_card<'a>(
+    p: &ExternalPlugin,
+    repository: Option<String>,
+    update_tag: Option<String>,
+    loaded: bool,
+    disabled: bool,
+    selected: bool,
+) -> Element<'a, Message> {
     let (status, kind) = if loaded && disabled {
         ("Disabled", StatusKind::Muted)
     } else if loaded {
@@ -116,7 +215,7 @@ fn external_card<'a>(p: &ExternalPlugin, loaded: bool, disabled: bool) -> Elemen
     } else {
         ("Restart to load", StatusKind::Warning)
     };
-    let mut header = row![
+    let header = row![
         text(p.name.clone()).size(15),
         Space::new().width(8),
         badge(format!("v{}", p.version)),
@@ -126,33 +225,55 @@ fn external_card<'a>(p: &ExternalPlugin, loaded: bool, disabled: bool) -> Elemen
         status_badge(status, kind),
     ]
     .align_y(iced::Center);
-    // A loaded plugin can be turned off (drops its ribbon tab + dispatch).
-    if loaded {
-        header = header.push(Space::new().width(10));
-        header = header.push(toggle_button(&p.id, disabled));
-    }
-    header = header.push(Space::new().width(6));
-    header = header.push(pill_button(
-        "Uninstall",
-        Message::PluginUninstall(p.id.clone()),
-        button::danger,
-    ));
 
-    let id_line = text(p.id.clone()).size(11).style(primary_style);
-    let mut body = column![header, id_line].spacing(5);
+    let id_line = text(p.id.clone()).size(11).style(muted_style);
+    let mut info_body = column![header, id_line].spacing(5);
     if !p.description.is_empty() {
-        body = body.push(text(p.description.clone()).size(12).style(muted_style));
+        info_body = info_body.push(text(p.description.clone()).size(12).style(muted_style));
     }
     if !p.command_prefixes.is_empty() {
-        body = body.push(
+        info_body = info_body.push(
             text(format!("Commands: {}", p.command_prefixes.join(", ")))
                 .size(11)
                 .style(muted_style),
         );
     }
-    container(body.padding([12, 14]))
+
+    let info: Element<'a, Message> = if let Some(repo) = repository.clone() {
+        button(info_body.width(Fill))
+            .width(Fill)
+            .padding(0)
+            .style(button::text)
+            .on_press(Message::PluginReadmeSelect(repo))
+            .into()
+    } else {
+        info_body.width(Fill).into()
+    };
+
+    let mut actions = row![Space::new().width(Fill)].align_y(iced::Center);
+    if let (Some(repo), Some(tag)) = (repository, update_tag) {
+        let label = format!("Update to {tag}");
+        actions = actions.push(pill_button(
+            &label,
+            Message::PluginUpdate(repo, tag),
+            button::primary,
+        ));
+        actions = actions.push(Space::new().width(6));
+    }
+    // A loaded plugin can be turned off (drops its ribbon tab + dispatch).
+    if loaded {
+        actions = actions.push(toggle_button(&p.id, disabled));
+        actions = actions.push(Space::new().width(6));
+    }
+    actions = actions.push(pill_button(
+        "Uninstall",
+        Message::PluginUninstall(p.id.clone()),
+        button::danger,
+    ));
+
+    container(column![info, actions].spacing(8).padding([10, 12]))
         .width(Fill)
-        .style(container::bordered_box)
+        .style(move |theme: &Theme| card_style(theme, selected))
         .into()
 }
 
@@ -221,74 +342,306 @@ fn install_controls<'a>(
     controls.into()
 }
 
-fn market_card<'a>(body: iced::widget::Column<'a, Message>) -> Element<'a, Message> {
+fn market_card<'a>(
+    body: iced::widget::Column<'a, Message>,
+    selected: bool,
+) -> Element<'a, Message> {
     container(body.spacing(4).padding([10, 12]))
         .width(Fill)
-        .style(container::bordered_box)
+        .style(move |theme: &Theme| card_style(theme, selected))
         .into()
 }
 
-fn marketplace_section<'a>(m: &MarketView) -> Element<'a, Message> {
+fn repository_display_name(repository: &str) -> String {
+    repository
+        .rsplit_once('/')
+        .map(|(_, name)| name)
+        .unwrap_or(repository)
+        .split(['-', '_'])
+        .filter(|part| !part.is_empty())
+        .map(|part| {
+            if part.eq_ignore_ascii_case("opencad") {
+                "OpenCAD".to_string()
+            } else {
+                let mut chars = part.chars();
+                chars
+                    .next()
+                    .map(|first| first.to_uppercase().collect::<String>() + chars.as_str())
+                    .unwrap_or_default()
+            }
+        })
+        .collect::<Vec<_>>()
+        .join(" ")
+}
+
+fn add_repository_card<'a>(m: &MarketView) -> Element<'a, Message> {
+    let form = row![
+        text_input("GitHub URL or owner/repository", m.input)
+            .on_input(Message::PluginRepoInput)
+            .on_submit(Message::PluginRepoAdd)
+            .size(13)
+            .width(Fill),
+        Space::new().width(8),
+        pill_button(
+            "Add repository",
+            Message::PluginRepoAdd,
+            button::primary,
+        ),
+    ]
+    .align_y(iced::Center);
+
+    market_card(
+        column![
+            text("Add from GitHub").size(14),
+            text(
+                "Paste a public repository URL. Compatible releases and the README \
+                 are detected automatically.",
+            )
+            .size(11)
+            .style(muted_style),
+            Space::new().height(3),
+            form,
+        ]
+        .spacing(5),
+        false,
+    )
+}
+
+fn marketplace_section<'a>(
+    m: &MarketView,
+    externals: &[ExternalPlugin],
+) -> Element<'a, Message> {
     let mut col = column![text("Available plugins").size(13).style(primary_style)].spacing(6);
+    let mut visible = 0usize;
 
     // Curated registry entries (from the OpenCADStudio repo).
     for e in m.registry {
+        if repository_is_installed(&e.repo, Some(&e.name), externals)
+            || !matches_search(m.search, &[&e.name, &e.description, &e.repo])
+        {
+            continue;
+        }
+        visible += 1;
         let tags = m.release_tags.get(&e.repo).cloned().unwrap_or_default();
         let selected = m.selected_tag.get(&e.repo).cloned();
-        let header = row![
-            text(e.name.clone()).size(14),
+        let mut info = column![text(e.name.clone()).size(14)].spacing(4);
+        if !e.description.is_empty() {
+            info = info.push(text(e.description.clone()).size(12).style(muted_style));
+        }
+        let info = button(info.width(Fill))
+            .width(Fill)
+            .padding(0)
+            .style(button::text)
+            .on_press(Message::PluginReadmeSelect(e.repo.clone()));
+        let actions = row![
             Space::new().width(Fill),
             install_controls(&e.repo, tags, selected, false),
         ]
         .align_y(iced::Center);
-        let mut body = column![header, text(e.repo.clone()).size(11).style(primary_style)];
-        if !e.description.is_empty() {
-            body = body.push(text(e.description.clone()).size(12).style(muted_style));
-        }
-        col = col.push(market_card(body));
+        col = col.push(market_card(
+            column![info, actions].spacing(8),
+            m.selected_repo == Some(e.repo.as_str()),
+        ));
     }
 
-    // Manual: link any repo by owner/repo.
-    col = col.push(Space::new().height(6));
-    col = col.push(text("Add a repository").size(12).style(muted_style));
-    col = col.push(
-        row![
-            text_input("owner/repo", m.input)
-                .on_input(Message::PluginRepoInput)
-                .on_submit(Message::PluginRepoAdd)
-                .size(13)
-                .width(Fill),
-            Space::new().width(8),
-            pill_button("Add", Message::PluginRepoAdd, button::primary),
-        ]
-        .align_y(iced::Center),
-    );
+    // User-linked repositories join the same catalog, but curated and installed
+    // repositories are suppressed so every plugin appears only once.
     for repo in m.repos {
+        if m.registry.iter().any(|entry| entry.repo == *repo)
+            || repository_is_installed(repo, None, externals)
+        {
+            continue;
+        }
+        let display_name = repository_display_name(repo);
+        if !matches_search(m.search, &[&display_name, repo]) {
+            continue;
+        }
+        visible += 1;
         let tags = m.release_tags.get(repo).cloned().unwrap_or_default();
         let selected = m.selected_tag.get(repo).cloned();
-        let header = row![
-            text(repo.clone()).size(13),
+        let info = button(
+            column![
+                text(display_name).size(14),
+                text("Added from GitHub").size(11).style(muted_style),
+            ]
+            .spacing(4)
+            .width(Fill),
+        )
+        .width(Fill)
+        .padding(0)
+        .style(button::text)
+        .on_press(Message::PluginReadmeSelect(repo.clone()));
+        let actions = row![
             Space::new().width(Fill),
             install_controls(repo, tags, selected, true),
         ]
         .align_y(iced::Center);
-        col = col.push(market_card(column![header]));
+        col = col.push(market_card(
+            column![info, actions].spacing(8),
+            m.selected_repo == Some(repo.as_str()),
+        ));
     }
 
+    if visible == 0 {
+        let message = if m.search.trim().is_empty() {
+            "No additional plugins are available."
+        } else {
+            "No available plugins match your search."
+        };
+        col = col.push(text(message).size(12).style(muted_style));
+    }
+
+    col = col.push(Space::new().height(8));
+    col = col.push(add_repository_card(m));
     if !m.status.is_empty() {
         col = col.push(text(m.status.to_string()).size(11).style(muted_style));
     }
     col.into()
 }
 
+fn resolve_readme_link(repo: &str, uri: &str) -> String {
+    if uri.starts_with("https://")
+        || uri.starts_with("http://")
+        || uri.starts_with("mailto:")
+    {
+        uri.to_string()
+    } else if uri.starts_with('/') {
+        format!("https://github.com{uri}")
+    } else if uri.starts_with('#') {
+        format!("https://github.com/{repo}{uri}")
+    } else {
+        format!(
+            "https://github.com/{repo}/blob/HEAD/{}",
+            uri.trim_start_matches("./")
+        )
+    }
+}
+
+fn readme_panel<'a>(market: &MarketView<'a>, theme: &Theme) -> Element<'a, Message> {
+    let Some(repo) = market.selected_repo else {
+        return container(
+            column![
+                text("Plugin details").size(16),
+                text("Select a plugin to read its GitHub README.")
+                    .size(12)
+                    .style(muted_style),
+            ]
+            .spacing(8),
+        )
+        .center(Fill)
+        .width(Fill)
+        .height(Fill)
+        .style(container::bordered_box)
+        .into();
+    };
+
+    let name = repo
+        .rsplit_once('/')
+        .map(|(_, name)| name)
+        .unwrap_or(repo)
+        .to_string();
+    let header = row![
+        column![
+            text(name).size(16),
+            text(repo.to_string()).size(11).style(primary_style),
+        ]
+        .spacing(3)
+        .width(Fill),
+        pill_button(
+            "View on GitHub",
+            Message::OpenUrl(format!("https://github.com/{repo}")),
+            button::secondary,
+        ),
+    ]
+    .align_y(iced::Center);
+
+    let content: Element<'a, Message> = if market.readme_loading.contains(repo) {
+        container(
+            column![
+                text("Loading README…").size(13),
+                text("Fetching the default branch from GitHub.")
+                    .size(11)
+                    .style(muted_style),
+            ]
+            .spacing(6),
+        )
+        .center(Fill)
+        .width(Fill)
+        .height(Fill)
+        .into()
+    } else {
+        match market.readmes.get(repo) {
+            Some(Ok(readme)) => {
+                let source_repo = repo.to_string();
+                markdown::view(
+                    readme.items(),
+                    markdown::Settings::with_text_size(13, theme),
+                )
+                .map(move |uri| {
+                    Message::OpenUrl(resolve_readme_link(&source_repo, &uri))
+                })
+            }
+            Some(Err(error)) => container(
+                column![
+                    text("README could not be loaded").size(14),
+                    text(error.clone()).size(11).style(muted_style),
+                    Space::new().height(4),
+                    pill_button(
+                        "Retry",
+                        Message::PluginReadmeSelect(repo.to_string()),
+                        button::secondary,
+                    ),
+                ]
+                .spacing(6),
+            )
+            .center(Fill)
+            .width(Fill)
+            .height(Fill)
+            .into(),
+            None => container(
+                text("Select the plugin again to load its README.")
+                    .size(12)
+                    .style(muted_style),
+            )
+            .center(Fill)
+            .width(Fill)
+            .height(Fill)
+            .into(),
+        }
+    };
+
+    let gutter = iced::Padding {
+        top: 8.0,
+        right: SCROLLBAR_GUTTER,
+        bottom: 8.0,
+        left: 0.0,
+    };
+    let readme = scrollable(container(content).padding(gutter))
+        .height(Fill)
+        .width(Fill);
+
+    container(
+        column![header, rule::horizontal(1), readme]
+            .spacing(10)
+            .padding([12, 14])
+            .width(Fill)
+            .height(Fill),
+    )
+    .width(Fill)
+    .height(Fill)
+    .style(container::bordered_box)
+    .into()
+}
+
 pub fn view_window<'a>(
     disabled: &FxHashSet<String>,
     externals: &[ExternalPlugin],
     loaded: &FxHashSet<String>,
-    market: MarketView,
+    market: MarketView<'a>,
+    theme: &'a Theme,
 ) -> Element<'a, Message> {
     let title = text("Plugins").size(20);
-    let subtitle = text("Add-ons load from the plugins folder. Install from a repository below.")
+    let subtitle = text("Browse, install, and manage add-ons. Select one to view its README.")
         .size(12)
         .style(muted_style);
 
@@ -297,24 +650,71 @@ pub fn view_window<'a>(
     if externals.is_empty() {
         list = list.push(text("No plugins installed yet.").size(13).style(muted_style));
     } else {
-        list = list.push(text("Installed").size(13).style(primary_style));
+        let mut visible_installed = 0usize;
         for p in externals {
+            let repository = repository_for_external(p, market.registry);
+            if !external_matches_search(p, repository.as_deref(), market.search) {
+                continue;
+            }
+            if visible_installed == 0 {
+                list = list.push(text("Installed").size(13).style(primary_style));
+            }
+            visible_installed += 1;
+            let selected = repository.as_deref() == market.selected_repo;
+            let update_tag = repository
+                .as_ref()
+                .and_then(|repo| market.release_tags.get(repo))
+                .and_then(|tags| newest_update(&p.version, tags));
             list = list.push(external_card(
                 p,
+                repository,
+                update_tag,
                 loaded.contains(&p.id),
                 disabled.contains(&p.id),
+                selected,
             ));
         }
+        if visible_installed == 0 && !market.search.trim().is_empty() {
+            list = list.push(
+                text("No installed plugins match your search.")
+                    .size(12)
+                    .style(muted_style),
+            );
+        }
     }
     // Marketplace: install from a linked repository's releases.
     list = list.push(Space::new().height(14));
-    list = list.push(marketplace_section(&market));
-    let body: Element<'_, Message> = scrollable(list.width(Fill)).height(Fill).into();
+    list = list.push(marketplace_section(&market, externals));
+    let gutter = iced::Padding {
+        top: 0.0,
+        right: SCROLLBAR_GUTTER,
+        bottom: 0.0,
+        left: 0.0,
+    };
+    let catalog = scrollable(container(list.width(Fill)).padding(gutter))
+        .height(Fill)
+        .width(Fill);
+    let search = text_input("Search plugins…", market.search)
+        .on_input(Message::PluginSearchInput)
+        .size(13)
+        .padding([7, 10])
+        .width(Fill);
+    let catalog_pane = column![search, catalog].spacing(10).width(Fill).height(Fill);
+    let details = readme_panel(&market, theme);
+    let body = row![
+        container(catalog_pane)
+            .width(Length::Fixed(410.0))
+            .height(Fill),
+        details,
+    ]
+    .spacing(14)
+    .height(Fill)
+    .width(Fill);
 
     container(
         column![title, subtitle, Space::new().height(12), body]
             .spacing(4)
-            .padding(20)
+            .padding(18)
             .width(Fill)
             .height(Fill),
     )
@@ -328,3 +728,27 @@ pub fn view_window<'a>(
     .height(Fill)
     .into()
 }
+
+#[cfg(test)]
+mod tests {
+    use super::{newest_update, repository_display_name};
+
+    #[test]
+    fn newest_update_uses_semver_not_release_order() {
+        let tags = vec![
+            "v1.4.0".to_string(),
+            "v2.0.0".to_string(),
+            "v1.9.9".to_string(),
+        ];
+        assert_eq!(newest_update("1.3.0", &tags).as_deref(), Some("v2.0.0"));
+        assert_eq!(newest_update("2.0.0", &tags), None);
+    }
+
+    #[test]
+    fn repository_name_is_human_readable() {
+        assert_eq!(
+            repository_display_name("owner/opencad-storm_sewer-plugin"),
+            "OpenCAD Storm Sewer Plugin",
+        );
+    }
+}