diff --git a/server/src/__tests__/board-access-denial.test.ts b/server/src/__tests__/board-access-denial.test.ts
index b8481f00127..166ddc0653a 100644
--- a/server/src/__tests__/board-access-denial.test.ts
+++ b/server/src/__tests__/board-access-denial.test.ts
@@ -58,6 +58,19 @@ describe("board-only denial", () => {
     expect(res.body.remediation).toContain(link);
   });
 
+  it("tells an agent denied any plugin route that every plugin management step is board-only", async () => {
+    // An agent asked to finish configuring a plugin usually reads the plugin list first.
+    // That denial must also settle configuration and secret binding, or the agent keeps
+    // searching the catalog for an agent route to them.
+    for (const path of ["/api/plugins", `/api/plugins/${AGENT_ID}/config`]) {
+      const res = await request(createApp(agentActor)).get(path).expect(403);
+      expect(res.body.remediation).toContain("Plugin management is board-only throughout");
+      expect(res.body.remediation).toContain("configuring (including choosing a secret for a plugin setting)");
+    }
+    const other = await request(createApp(agentActor)).post(`/api/companies/${COMPANY_ID}/secrets`).expect(403);
+    expect(other.body.remediation).not.toContain("Plugin management");
+  });
+
   it("links the resolved project when an agent names the project by its short reference", async () => {
     const app = express();
     app.use((req, _res, next) => {
diff --git a/server/src/routes/authz.ts b/server/src/routes/authz.ts
index e744ceb15d3..e2482253172 100644
--- a/server/src/routes/authz.ts
+++ b/server/src/routes/authz.ts
@@ -81,8 +81,17 @@ function pluginControlPage(path: string): [string, string] | null {
     : ["plugin settings", "/<prefix>/company/settings/instance/plugins"];
 }
 
+// Every plugin management route is board-only, so a denial on any one of them
+// (often the list an agent reads first) also answers the plugin's other management steps.
+const PLUGIN_ROUTE = /^\/plugins(?:\/|$)/;
+const PLUGIN_ADMINISTRATION_SCOPE = "Plugin management is board-only throughout: listing, installing, configuring (including choosing a secret for a plugin setting), enabling, disabling, upgrading and removing plugins have no agent route either.";
+
+function deniedApiPath(req: Request) {
+  return (req.originalUrl ?? "").split("?")[0]!.replace(/^\/api(?=\/)/, "");
+}
+
 function boardControlPage(req: Request) {
-  const path = (req.originalUrl ?? "").split("?")[0]!.replace(/^\/api(?=\/)/, "");
+  const path = deniedApiPath(req);
   const pluginPage = pluginControlPage(path);
   if (pluginPage) return pluginPage;
   for (const [pattern, page] of BOARD_CONTROL_PAGES) {
@@ -99,12 +108,13 @@ function boardControlPage(req: Request) {
 export function boardAccessRequired(req: Request) {
   if (req.actor.type !== "agent") return forbidden("Board access required");
   const page = boardControlPage(req);
+  const scope = PLUGIN_ROUTE.test(deniedApiPath(req)) ? `${PLUGIN_ADMINISTRATION_SCOPE} ` : "";
   const where = page
     ? `They can do it in the Paperclip web app: link [Open ${page[0]}](${page[1]}), with this conversation's company prefix as <prefix>.`
     : "They can do it in the Paperclip web app or with their own board credentials. Link a page only if you already know its route; do not search for one.";
   return forbidden("Board access required", {
     code: BOARD_ACCESS_REQUIRED_CODE,
-    remediation: `This action is board-only by design and this denial is final: no agent credential, tool or other API route can do it, so do not search for one. Stop working on this step and reply now: tell the person that a board user must do it. ${where}`,
+    remediation: `This action is board-only by design and this denial is final: no agent credential, tool or other API route can do it, so do not search for one. Stop working on this step and reply now: tell the person that a board user must do it. ${scope}${where}`,
   });
 }