refactor(rules): delegate injectors to rules-core

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/hooks/directory-agents-injector/finder.ts

@@ -1,7 +1,6 @@
-import { constants, promises as fsPromises } from "node:fs";
-import { dirname, isAbsolute, join, resolve } from "node:path";
-
-import { AGENTS_FILENAME } from "./constants";
+import { findAgentsMdUp as findAgentsMdUpCore } from "@oh-my-opencode/rules-core";
+import type { AgentsMdCache } from "@oh-my-opencode/rules-core";
+import { isAbsolute, resolve } from "node:path";
 
 export function resolveFilePath(rootDirectory: string, path: string): string | null {
   if (!path) return null;
@@ -10,33 +9,9 @@ export function resolveFilePath(rootDirectory: string, path: string): string | n
 }
 
 export async function findAgentsMdUp(input: {
-  startDir: string;
-  rootDir: string;
+  readonly startDir: string;
+  readonly rootDir: string;
+  readonly cache?: AgentsMdCache;
 }): Promise<string[]> {
-  const found: string[] = [];
-  let current = input.startDir;
-
-  while (true) {
-    // Skip root AGENTS.md - OpenCode's system.ts already loads it via custom()
-    // See: https://github.com/code-yeongyu/oh-my-openagent/issues/379
-    const isRootDir = current === input.rootDir;
-    if (!isRootDir) {
-      const agentsPath = join(current, AGENTS_FILENAME);
-      const exists = await fsPromises
-        .access(agentsPath, constants.F_OK)
-        .then(() => true)
-        .catch(() => false);
-      if (exists) {
-        found.push(agentsPath);
-      }
-    }
-
-    if (isRootDir) break;
-    const parent = dirname(current);
-    if (parent === current) break;
-    if (!parent.startsWith(input.rootDir)) break;
-    current = parent;
-  }
-
-  return found.reverse();
+  return findAgentsMdUpCore({ startDir: input.startDir, rootDir: input.rootDir, cache: input.cache });
 }

src/hooks/directory-agents-injector/hook.ts

@@ -1,3 +1,4 @@
+import { createAgentsMdCache } from "@oh-my-opencode/rules-core";
 import type { PluginInput } from "@opencode-ai/plugin";
 
 import { createDynamicTruncator } from "../../shared/dynamic-truncator";
@@ -35,6 +36,7 @@ export function createDirectoryAgentsInjectorHook(
   modelCacheState?: { anthropicContext1MEnabled: boolean },
 ): DirectoryAgentsInjectorHook {
   const sessionCaches = new Map<string, Set<string>>();
+  const agentsMdCache = createAgentsMdCache();
   const truncator = createDynamicTruncator(ctx, modelCacheState);
 
   const toolExecuteAfter = async (input: ToolExecuteInput, output: ToolExecuteOutput) => {
@@ -45,6 +47,7 @@ export function createDirectoryAgentsInjectorHook(
         ctx,
         truncator,
         sessionCaches,
+        agentsMdCache,
         filePath: output.title,
         sessionID: input.sessionID,
         output,
@@ -54,21 +57,21 @@ export function createDirectoryAgentsInjectorHook(
   };
 
   const eventHandler = async ({ event }: EventInput) => {
-    const props = event.properties as Record<string, unknown> | undefined;
-
     if (event.type === "session.deleted") {
-      const sessionID = resolveSessionEventID(props);
+      const sessionID = resolveSessionEventID(event.properties);
       if (sessionID) {
         sessionCaches.delete(sessionID);
         clearInjectedPaths(sessionID);
+        agentsMdCache.clear();
       }
     }
 
     if (event.type === "session.compacted") {
-      const sessionID = resolveSessionEventID(props);
+      const sessionID = resolveSessionEventID(event.properties);
       if (sessionID) {
         sessionCaches.delete(sessionID);
         clearInjectedPaths(sessionID);
+        agentsMdCache.clear();
       }
     }
   };

src/hooks/directory-agents-injector/injector.ts

@@ -1,4 +1,5 @@
 import type { PluginInput } from "@opencode-ai/plugin";
+import type { AgentsMdCache } from "@oh-my-opencode/rules-core";
 import { promises as fsPromises } from "node:fs";
 import { dirname } from "node:path";
 
@@ -15,13 +16,18 @@ function getSessionCache(
   if (!sessionCaches.has(sessionID)) {
     sessionCaches.set(sessionID, loadInjectedPaths(sessionID));
   }
-  return sessionCaches.get(sessionID)!;
+  const cache = sessionCaches.get(sessionID);
+  if (cache) return cache;
+  const loaded = loadInjectedPaths(sessionID);
+  sessionCaches.set(sessionID, loaded);
+  return loaded;
 }
 
 export async function processFilePathForAgentsInjection(input: {
   ctx: PluginInput;
   truncator: DynamicTruncator;
   sessionCaches: Map<string, Set<string>>;
+  agentsMdCache?: AgentsMdCache;
   filePath: string;
   sessionID: string;
   output: { title: string; output: string; metadata: unknown };
@@ -35,26 +41,29 @@ export async function processFilePathForAgentsInjection(input: {
 
   const dir = dirname(resolved);
   const cache = getSessionCache(input.sessionCaches, input.sessionID);
-  const agentsPaths = await findAgentsMdUp({ startDir: dir, rootDir: input.ctx.directory });
+  const agentsPaths = await findAgentsMdUp({
+    startDir: dir,
+    rootDir: input.ctx.directory,
+    cache: input.agentsMdCache,
+  });
 
   let dirty = false;
   for (const agentsPath of agentsPaths) {
     const agentsDir = dirname(agentsPath);
     if (cache.has(agentsDir)) continue;
 
-    try {
-      const content = await fsPromises.readFile(agentsPath, "utf-8");
-      cache.add(agentsDir);
-      const { result, truncated } = await input.truncator.truncate(
-        input.sessionID,
-        content,
-      );
-      const truncationNotice = truncated
-        ? `\n\n[Note: Content was truncated to save context window space. For full context, please read the file directly: ${agentsPath}]`
-        : "";
-      input.output.output += `\n\n[Directory Context: ${agentsPath}]\n${result}${truncationNotice}`;
-      dirty = true;
-    } catch {}
+    const content = await fsPromises.readFile(agentsPath, "utf-8").catch(() => null);
+    if (content === null) continue;
+    cache.add(agentsDir);
+    const { result, truncated } = await input.truncator.truncate(
+      input.sessionID,
+      content,
+    );
+    const truncationNotice = truncated
+      ? `\n\n[Note: Content was truncated to save context window space. For full context, please read the file directly: ${agentsPath}]`
+      : "";
+    input.output.output += `\n\n[Directory Context: ${agentsPath}]\n${result}${truncationNotice}`;
+    dirty = true;
   }
 
   if (dirty) {