fix(cursor): user-invoked skills hidden from the model reach the Cursor prompt

packages/provider-cursor/src/server/adapter.test.ts

@@ -2064,6 +2064,12 @@ describe("CursorAdapterV2", () => {
           path.join(skill, "SKILL.md"),
           "# Review\nReview the code.",
         );
+        const userOnlySkill = path.join(workspace, ".cursor", "skills", "grill-me");
+        yield* fileSystem.makeDirectory(userOnlySkill, { recursive: true });
+        yield* fileSystem.writeFileString(
+          path.join(userOnlySkill, "SKILL.md"),
+          "---\nname: grill-me\ndescription: Grill the plan.\ndisable-model-invocation: true\n---\nAsk one question at a time.",
+        );
         const steered: string[] = [];
         let cancelled = 0;
         let outcome: "complete_delivered" | "revert_to_followup" = "complete_delivered";
@@ -2198,6 +2204,21 @@ describe("CursorAdapterV2", () => {
         });
         assert.deepEqual(steered, ["/review Look at the tests instead."]);
         assert.equal(cancelled, 0);
+        yield* runtime.steerTurn({
+          threadId,
+          runId: turn.runId,
+          providerThread,
+          providerTurnId,
+          message: {
+            messageId: MessageId.make("cursor-steer-user-only-skill"),
+            createdBy: "user",
+            creationSource: "web",
+            text: "$grill-me My plan.",
+            attachments: [],
+          },
+        });
+        // Cursor hides `disable-model-invocation` skills from the model, so the SDK prompt must carry them.
+        assert.include(steered.at(-1), "Ask one question at a time.");
 
         outcome = "revert_to_followup";
         const declined = yield* runtime
@@ -2216,7 +2237,7 @@ describe("CursorAdapterV2", () => {
           })
           .pipe(Effect.exit);
         if (!Exit.isFailure(declined)) return yield* Effect.die("Expected a declined steer");
-        assert.deepEqual(steered, ["/review Look at the tests instead.", "Stop and do this."]);
+        assert.equal(steered.at(-1), "Stop and do this.");
         assert.equal(cancelled, 0);
         const declinedError = Cause.squash(declined.cause);
         assert.instanceOf(declinedError, ProviderAdapter.ProviderAdapterSteerDeclinedError);

packages/provider-cursor/src/server/adapter.ts

@@ -28,6 +28,7 @@ import {
   type OrchestrationV2TurnItem,
   type ProviderInstanceId,
   type ServerProviderModel,
+  type ServerProviderSkill,
   type ThreadId,
 } from "@t3tools/contracts";
 import * as DateTime from "effect/DateTime";
@@ -48,6 +49,8 @@ import * as McpProviderSession from "@t3tools/provider-core/server/mcpSession";
 import { CursorTransportFailure } from "./transportFailure.ts";
 import { cursorContextWindowTokens, cursorSdkModelSelection } from "./sdkModel.ts";
 import {
+  appendCursorInvokedSkills,
+  cursorSlashSkillNames,
   discoverCursorSkills,
   hasCursorSkillMention,
   rewriteCursorSkillMentions,
@@ -2309,23 +2312,36 @@ export const makeCursorAdapterV2 = Effect.fn("makeCursorAdapterV2")(function* (
           return next;
         });
 
-        let cursorSkillNames: ReadonlySet<string> | undefined;
+        let cursorSkills: ReadonlyMap<string, ServerProviderSkill> | undefined;
         const resolveCursorSkillText = Effect.fn("CursorAdapterV2.resolveCursorSkillText")(
           function* (rawText: string, cwd: string | undefined) {
-            if (hasCursorSkillMention(rawText) && cursorSkillNames === undefined) {
+            if (
+              cursorSkills === undefined &&
+              (hasCursorSkillMention(rawText) || cursorSlashSkillNames(rawText).size > 0)
+            ) {
               const skills = yield* discoverCursorSkills(cwd, adapterOptions.environment).pipe(
                 Effect.provideService(FileSystem.FileSystem, fileSystem),
                 Effect.provideService(Path.Path, path),
               );
-              cursorSkillNames = new Set(
+              cursorSkills = new Map(
                 skills
                   .filter((skill) => skill.enabled && skill.userInvocable !== false)
-                  .map((skill) => skill.name),
+                  .map((skill) => [skill.name, skill]),
               );
             }
-            return cursorSkillNames === undefined
-              ? rawText
-              : rewriteCursorSkillMentions(rawText, cursorSkillNames);
+            if (cursorSkills === undefined) return rawText;
+            const skillsByName = cursorSkills;
+            const text = rewriteCursorSkillMentions(rawText, new Set(skillsByName.keys()));
+            const invoked = yield* Effect.forEach(cursorSlashSkillNames(text), (name) => {
+              const skill = skillsByName.get(name);
+              return skill?.userInvocationOnly === true
+                ? fileSystem.readFileString(skill.path).pipe(
+                    Effect.map((contents) => [{ name, contents }]),
+                    Effect.orElseSucceed(() => []),
+                  )
+                : Effect.succeed([]);
+            });
+            return appendCursorInvokedSkills(text, invoked.flat());
           },
         );
         const resolveUserMessage = Effect.fnUntraced(function* (

packages/provider-cursor/src/server/skills.ts

@@ -14,6 +14,7 @@ const FRONTMATTER_PATTERN = /^---\r?\n([\s\S]*?)\r?\n---(?:\r?\n|$)/;
 const SKILL_MENTION_PATTERN =
   /(^|\s)\p{Sc}(?![0-9][0-9_]*(?:[kKmMbBtT]|[eE][0-9]+)?(?:\s|$))(?=[a-zA-Z0-9:_-]*[a-zA-Z])([a-zA-Z0-9][a-zA-Z0-9:_-]*)(?=\s|$)/gu;
 const HAS_SKILL_MENTION_PATTERN = new RegExp(SKILL_MENTION_PATTERN.source, "u");
+const SLASH_SKILL_PATTERN = /(?:^|\s)\/([a-zA-Z0-9][a-zA-Z0-9:_-]*)(?=\s|$)/gu;
 const MAX_SKILL_DEPTH = 10;
 const MAX_SKILL_BYTES = ByteSize.bytes(1_000_000);
 const MAX_SKILL_SCAN_ENTRIES = 10_000;
@@ -305,3 +306,21 @@ export function rewriteCursorSkillMentions(
     skillNames.has(name) ? `${prefix}/${name}` : match,
   );
 }
+
+/** Names invoked as `/name`, the form Cursor uses and `rewriteCursorSkillMentions` produces. */
+export function cursorSlashSkillNames(prompt: string): ReadonlySet<string> {
+  return new Set(Array.from(prompt.matchAll(SLASH_SKILL_PATTERN), (match) => match[1] ?? ""));
+}
+
+/** Cursor hides `disable-model-invocation` skills from the model, so the prompt carries them. */
+export function appendCursorInvokedSkills(
+  prompt: string,
+  skills: ReadonlyArray<{ readonly name: string; readonly contents: string }>,
+): string {
+  if (skills.length === 0) return prompt;
+  const blocks = skills.map(
+    (skill) =>
+      `<skill name="${skill.name}">\n${skill.contents.replace(FRONTMATTER_PATTERN, "").trim()}\n</skill>`,
+  );
+  return `${prompt}\n\nThe user invoked these skills. Follow their instructions:\n\n${blocks.join("\n\n")}`;
+}