diff --git a/src/config/schema/agent-definitions.ts b/src/config/schema/agent-definitions.ts
index 508bfde0b..328238e2c 100644
--- a/src/config/schema/agent-definitions.ts
+++ b/src/config/schema/agent-definitions.ts
@@ -1,5 +1,5 @@
 import { z } from "zod"
 
-export const AgentDefinitionPathSchema = z.string()
+export const AgentDefinitionPathSchema = z.string().min(1)
 
 export const AgentDefinitionsConfigSchema = z.array(AgentDefinitionPathSchema).optional()
diff --git a/src/features/claude-code-agent-loader/agent-definitions-loader.ts b/src/features/claude-code-agent-loader/agent-definitions-loader.ts
index 0736fe347..383f69387 100644
--- a/src/features/claude-code-agent-loader/agent-definitions-loader.ts
+++ b/src/features/claude-code-agent-loader/agent-definitions-loader.ts
@@ -2,23 +2,11 @@ import { existsSync, readFileSync } from "fs"
 import { basename, extname } from "path"
 import { parseFrontmatter } from "../../shared/frontmatter"
 import { log } from "../../shared/logger"
+import { parseToolsConfig } from "../../shared/parse-tools-config"
 import { parseJsonAgentFile } from "./json-agent-loader"
 import { mapClaudeModelToOpenCode } from "./claude-model-mapper"
 import type { AgentScope, AgentFrontmatter, ClaudeCodeAgentConfig, LoadedAgent } from "./types"
 
-function parseToolsConfig(toolsStr?: string): Record<string, boolean> | undefined {
-  if (!toolsStr) return undefined
-
-  const tools = toolsStr.split(",").map((t) => t.trim()).filter(Boolean)
-  if (tools.length === 0) return undefined
-
-  const result: Record<string, boolean> = {}
-  for (const tool of tools) {
-    result[tool.toLowerCase()] = true
-  }
-  return result
-}
-
 export function parseMarkdownAgentFile(filePath: string, scope: AgentScope): LoadedAgent | null {
   try {
     if (!existsSync(filePath)) {
@@ -67,7 +55,7 @@ export function loadAgentDefinitions(
   paths: string[],
   scope: AgentScope
 ): Record<string, ClaudeCodeAgentConfig> {
-  const result: Record<string, ClaudeCodeAgentConfig> = {}
+  const result: Record<string, ClaudeCodeAgentConfig> = Object.create(null)
 
   for (const filePath of paths) {
     if (!existsSync(filePath)) {
diff --git a/src/features/claude-code-agent-loader/json-agent-loader.ts b/src/features/claude-code-agent-loader/json-agent-loader.ts
index 394d2a25c..fa135fa6f 100644
--- a/src/features/claude-code-agent-loader/json-agent-loader.ts
+++ b/src/features/claude-code-agent-loader/json-agent-loader.ts
@@ -1,23 +1,9 @@
 import { existsSync, readFileSync } from "fs"
 import { parseJsoncSafe } from "../../shared/jsonc-parser"
+import { parseToolsConfig } from "../../shared/parse-tools-config"
 import { mapClaudeModelToOpenCode } from "./claude-model-mapper"
 import type { AgentScope, AgentJsonDefinition, ClaudeCodeAgentConfig, LoadedAgent } from "./types"
 
-function parseToolsConfig(tools?: string | string[]): Record<string, boolean> | undefined {
-  if (!tools) return undefined
-
-  const toolsArray = Array.isArray(tools) ? tools : tools.split(",").map((t) => t.trim())
-  const filtered = toolsArray.filter((t) => typeof t === "string" && t.length > 0)
-
-  if (filtered.length === 0) return undefined
-
-  const result: Record<string, boolean> = {}
-  for (const tool of filtered) {
-    result[tool.toLowerCase()] = true
-  }
-  return result
-}
-
 export function parseJsonAgentFile(filePath: string, scope: AgentScope): LoadedAgent | null {
   try {
     if (!existsSync(filePath)) {
diff --git a/src/features/claude-code-agent-loader/loader.ts b/src/features/claude-code-agent-loader/loader.ts
index 5a1bbf8fd..380f479eb 100644
--- a/src/features/claude-code-agent-loader/loader.ts
+++ b/src/features/claude-code-agent-loader/loader.ts
@@ -32,7 +32,7 @@ export function loadUserAgents(): Record<string, ClaudeCodeAgentConfig> {
   const userAgentsDir = join(getClaudeConfigDir(), "agents")
   const agents = loadAgentsFromDir(userAgentsDir, "user")
 
-  const result: Record<string, ClaudeCodeAgentConfig> = {}
+  const result: Record<string, ClaudeCodeAgentConfig> = Object.create(null)
   for (const agent of agents) {
     result[agent.name] = agent.config
   }
@@ -43,7 +43,7 @@ export function loadProjectAgents(directory?: string): Record<string, ClaudeCode
   const projectAgentsDir = join(directory ?? process.cwd(), ".claude", "agents")
   const agents = loadAgentsFromDir(projectAgentsDir, "project")
 
-  const result: Record<string, ClaudeCodeAgentConfig> = {}
+  const result: Record<string, ClaudeCodeAgentConfig> = Object.create(null)
   for (const agent of agents) {
     result[agent.name] = agent.config
   }
@@ -55,7 +55,7 @@ export function loadOpencodeGlobalAgents(): Record<string, ClaudeCodeAgentConfig
   const opencodeAgentsDir = join(configDir, "agents")
   const agents = loadAgentsFromDir(opencodeAgentsDir, "opencode")
 
-  const result: Record<string, ClaudeCodeAgentConfig> = {}
+  const result: Record<string, ClaudeCodeAgentConfig> = Object.create(null)
   for (const agent of agents) {
     result[agent.name] = agent.config
   }
@@ -66,7 +66,7 @@ export function loadOpencodeProjectAgents(directory?: string): Record<string, Cl
   const opencodeProjectDir = join(directory ?? process.cwd(), ".opencode", "agents")
   const agents = loadAgentsFromDir(opencodeProjectDir, "opencode-project")
 
-  const result: Record<string, ClaudeCodeAgentConfig> = {}
+  const result: Record<string, ClaudeCodeAgentConfig> = Object.create(null)
   for (const agent of agents) {
     result[agent.name] = agent.config
   }
diff --git a/src/features/claude-code-agent-loader/opencode-config-agents-reader.test.ts b/src/features/claude-code-agent-loader/opencode-config-agents-reader.test.ts
index 52ed83da3..1f7a48deb 100644
--- a/src/features/claude-code-agent-loader/opencode-config-agents-reader.test.ts
+++ b/src/features/claude-code-agent-loader/opencode-config-agents-reader.test.ts
@@ -1,11 +1,26 @@
-import { describe, expect, it } from "bun:test"
+import { describe, expect, it, beforeEach, afterEach } from "bun:test"
+import { mock } from "bun:test"
 import * as fs from "node:fs"
 import * as os from "node:os"
 import * as path from "node:path"
 
-import { readOpencodeConfigAgents } from "./opencode-config-agents-reader"
+// Mock getOpenCodeConfigDir to prevent global config leakage
+let mockGlobalConfigDir: string
+mock.module("../../shared/opencode-config-dir", () => ({
+  getOpenCodeConfigDir: () => mockGlobalConfigDir,
+}))
+
+const { readOpencodeConfigAgents } = require("./opencode-config-agents-reader")
 
 describe("readOpencodeConfigAgents", () => {
+  beforeEach(() => {
+    mockGlobalConfigDir = fs.mkdtempSync(path.join(os.tmpdir(), "opencode-mock-global-"))
+  })
+
+  afterEach(() => {
+    fs.rmSync(mockGlobalConfigDir, { recursive: true, force: true })
+  })
+
   it("returns empty record when no opencode.json exists", () => {
     const nonexistentDir = "/nonexistent/directory/path"
     const result = readOpencodeConfigAgents(nonexistentDir)
diff --git a/src/features/claude-code-agent-loader/opencode-config-agents-reader.ts b/src/features/claude-code-agent-loader/opencode-config-agents-reader.ts
index 5b3f41a75..480fdbe68 100644
--- a/src/features/claude-code-agent-loader/opencode-config-agents-reader.ts
+++ b/src/features/claude-code-agent-loader/opencode-config-agents-reader.ts
@@ -3,6 +3,8 @@ import * as path from "node:path"
 
 import { getOpenCodeConfigDir } from "../../shared/opencode-config-dir"
 import { parseJsoncSafe } from "../../shared/jsonc-parser"
+import { parseToolsConfig } from "../../shared/parse-tools-config"
+import { resolveAgentDefinitionPaths } from "../../shared/resolve-agent-definition-paths"
 import { loadAgentDefinitions } from "./agent-definitions-loader"
 import { mapClaudeModelToOpenCode } from "./claude-model-mapper"
 import type { ClaudeCodeAgentConfig } from "./types"
@@ -25,28 +27,6 @@ function getConfigPaths(directory: string): string[] {
   return paths
 }
 
-function parseToolsConfig(toolsValue: unknown): Record<string, boolean> | undefined {
-  if (!toolsValue) return undefined
-
-  let toolsStr: string
-  if (typeof toolsValue === "string") {
-    toolsStr = toolsValue
-  } else if (Array.isArray(toolsValue)) {
-    toolsStr = toolsValue.filter((t) => typeof t === "string").join(",")
-  } else {
-    return undefined
-  }
-
-  const tools = toolsStr.split(",").map((t) => t.trim()).filter(Boolean)
-  if (tools.length === 0) return undefined
-
-  const result: Record<string, boolean> = {}
-  for (const tool of tools) {
-    result[tool.toLowerCase()] = true
-  }
-  return result
-}
-
 function convertInlineAgent(agentData: unknown): ClaudeCodeAgentConfig | null {
   if (!agentData || typeof agentData !== "object") {
     return null
@@ -63,9 +43,15 @@ function convertInlineAgent(agentData: unknown): ClaudeCodeAgentConfig | null {
     ? `${mappedModel.providerID}/${mappedModel.modelID}`
     : undefined
 
+  const VALID_MODES = ["subagent", "primary", "all"] as const
+  const rawMode = typeof agent.mode === "string" ? agent.mode : undefined
+  const mode = rawMode && (VALID_MODES as readonly string[]).includes(rawMode)
+    ? (rawMode as "subagent" | "primary" | "all")
+    : "subagent"
+
   const config: ClaudeCodeAgentConfig = {
     description,
-    mode: (agent.mode as "subagent" | "primary" | "all") || "subagent",
+    mode,
     prompt: agent.prompt ? String(agent.prompt) : "",
     ...(modelString ? { model: modelString } : {}),
   }
@@ -106,9 +92,7 @@ export function readOpencodeConfigAgents(directory: string): Record<string, Clau
 
       if (parseResult.data.agent_definitions) {
         const definitionPaths = extractDefinitionPaths(parseResult.data.agent_definitions)
-        const resolvedPaths = definitionPaths.map((p) =>
-          path.isAbsolute(p) ? p : path.resolve(configDir, p)
-        )
+        const resolvedPaths = resolveAgentDefinitionPaths(definitionPaths, configDir, directory)
 
         const definitionAgents = loadAgentDefinitions(resolvedPaths, "opencode-config")
 
diff --git a/src/features/claude-code-plugin-loader/agent-loader.ts b/src/features/claude-code-plugin-loader/agent-loader.ts
index 1aff57e0c..128b9f229 100644
--- a/src/features/claude-code-plugin-loader/agent-loader.ts
+++ b/src/features/claude-code-plugin-loader/agent-loader.ts
@@ -3,27 +3,11 @@ import { basename, join } from "path"
 import { parseFrontmatter } from "../../shared/frontmatter"
 import { isMarkdownFile } from "../../shared/file-utils"
 import { log } from "../../shared/logger"
+import { parseToolsConfig } from "../../shared/parse-tools-config"
 import type { AgentFrontmatter, ClaudeCodeAgentConfig } from "../claude-code-agent-loader/types"
 import { mapClaudeModelToOpenCode } from "../claude-code-agent-loader/claude-model-mapper"
 import type { LoadedPlugin } from "./types"
 
-function parseToolsConfig(toolsStr?: string): Record<string, boolean> | undefined {
-  if (!toolsStr) return undefined
-
-  const tools = toolsStr
-    .split(",")
-    .map((tool) => tool.trim())
-    .filter(Boolean)
-
-  if (tools.length === 0) return undefined
-
-  const result: Record<string, boolean> = {}
-  for (const tool of tools) {
-    result[tool.toLowerCase()] = true
-  }
-  return result
-}
-
 export function loadPluginAgents(plugins: LoadedPlugin[]): Record<string, ClaudeCodeAgentConfig> {
   const agents: Record<string, ClaudeCodeAgentConfig> = {}
 
diff --git a/src/shared/index.ts b/src/shared/index.ts
index cf9792361..826434d42 100644
--- a/src/shared/index.ts
+++ b/src/shared/index.ts
@@ -76,3 +76,4 @@ export { SessionCategoryRegistry } from "./session-category-registry"
 export * from "./plugin-identity"
 export * from "./log-legacy-plugin-startup-warning"
 export * from "./task-system-enabled"
+export * from "./parse-tools-config"
diff --git a/src/shared/parse-tools-config.ts b/src/shared/parse-tools-config.ts
new file mode 100644
index 000000000..bc5f50169
--- /dev/null
+++ b/src/shared/parse-tools-config.ts
@@ -0,0 +1,25 @@
+/**
+ * Parses a tools configuration value into a boolean record.
+ * Accepts comma-separated strings, string arrays, or unknown values from config files.
+ * Returns undefined when input is empty or invalid.
+ */
+export function parseToolsConfig(toolsValue: unknown): Record<string, boolean> | undefined {
+  if (!toolsValue) return undefined
+
+  let items: string[]
+  if (typeof toolsValue === "string") {
+    items = toolsValue.split(",").map((t) => t.trim()).filter(Boolean)
+  } else if (Array.isArray(toolsValue)) {
+    items = toolsValue.filter((t) => typeof t === "string" && t.trim().length > 0).map((t) => (t as string).trim())
+  } else {
+    return undefined
+  }
+
+  if (items.length === 0) return undefined
+
+  const result: Record<string, boolean> = {}
+  for (const tool of items) {
+    result[tool.toLowerCase()] = true
+  }
+  return result
+}
diff --git a/src/shared/resolve-agent-definition-paths.test.ts b/src/shared/resolve-agent-definition-paths.test.ts
new file mode 100644
index 000000000..fcc14be7a
--- /dev/null
+++ b/src/shared/resolve-agent-definition-paths.test.ts
@@ -0,0 +1,122 @@
+import { describe, test, expect, beforeEach, afterEach } from "bun:test"
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from "fs"
+import { join } from "path"
+import { homedir } from "os"
+import { tmpdir } from "os"
+
+import { resolveAgentDefinitionPaths } from "./resolve-agent-definition-paths"
+
+describe("resolveAgentDefinitionPaths", () => {
+  let tempDir: string
+
+  beforeEach(() => {
+    tempDir = mkdtempSync(join(tmpdir(), "resolve-agent-def-paths-"))
+  })
+
+  afterEach(() => {
+    rmSync(tempDir, { recursive: true, force: true })
+  })
+
+  describe("#given relative paths", () => {
+    test("#then they are resolved against baseDir", () => {
+      const result = resolveAgentDefinitionPaths(
+        ["agents/my-agent.md"],
+        tempDir,
+        null,
+      )
+
+      expect(result).toEqual([join(tempDir, "agents/my-agent.md")])
+    })
+  })
+
+  describe("#given absolute paths", () => {
+    test("#then they are returned as-is", () => {
+      const absPath = join(tempDir, "absolute-agent.md")
+
+      const result = resolveAgentDefinitionPaths(
+        [absPath],
+        "/some/other/base",
+        null,
+      )
+
+      expect(result).toEqual([absPath])
+    })
+  })
+
+  describe("#given tilde-prefixed paths", () => {
+    test("#then ~ is expanded to homedir", () => {
+      const result = resolveAgentDefinitionPaths(
+        ["~/agents/test.md"],
+        tempDir,
+        null,
+      )
+
+      expect(result).toEqual([join(homedir(), "agents/test.md")])
+    })
+  })
+
+  describe("#given containmentDir is set", () => {
+    test("#then paths outside the boundary are rejected", () => {
+      const projectDir = join(tempDir, "project")
+      mkdirSync(projectDir, { recursive: true })
+
+      const result = resolveAgentDefinitionPaths(
+        ["/etc/passwd"],
+        projectDir,
+        projectDir,
+      )
+
+      expect(result).toEqual([])
+    })
+
+    test("#then paths inside the boundary are allowed", () => {
+      const projectDir = join(tempDir, "project")
+      const agentsDir = join(projectDir, "agents")
+      mkdirSync(agentsDir, { recursive: true })
+      writeFileSync(join(agentsDir, "a.md"), "test", "utf-8")
+
+      const result = resolveAgentDefinitionPaths(
+        ["agents/a.md"],
+        projectDir,
+        projectDir,
+      )
+
+      expect(result).toEqual([join(projectDir, "agents/a.md")])
+    })
+  })
+
+  describe("#given containmentDir is null", () => {
+    test("#then no boundary check is applied", () => {
+      const result = resolveAgentDefinitionPaths(
+        ["/some/outside/path/agent.md"],
+        tempDir,
+        null,
+      )
+
+      expect(result).toEqual(["/some/outside/path/agent.md"])
+    })
+  })
+
+  describe("#given an empty paths array", () => {
+    test("#then an empty array is returned", () => {
+      const result = resolveAgentDefinitionPaths([], tempDir, null)
+
+      expect(result).toEqual([])
+    })
+  })
+
+  describe("#given mixed valid and invalid paths", () => {
+    test("#then only valid paths within the boundary are returned", () => {
+      const projectDir = join(tempDir, "project")
+      mkdirSync(projectDir, { recursive: true })
+
+      const result = resolveAgentDefinitionPaths(
+        ["./valid.md", "/outside/boundary.md"],
+        projectDir,
+        projectDir,
+      )
+
+      expect(result).toEqual([join(projectDir, "valid.md")])
+    })
+  })
+})
diff --git a/src/tools/call-omo-agent/agent-resolver.test.ts b/src/tools/call-omo-agent/agent-resolver.test.ts
index cadd0c99f..f2e13022b 100644
--- a/src/tools/call-omo-agent/agent-resolver.test.ts
+++ b/src/tools/call-omo-agent/agent-resolver.test.ts
@@ -12,8 +12,8 @@
  * R6: No duplicate agent names in output
  * R7: Malformed agent entries (null, missing name, non-string name, whitespace-only) are skipped gracefully
  */
-const { describe, test, expect, mock } = require("bun:test")
-const { resolveCallableAgents } = require("./agent-resolver")
+const { describe, test, expect, mock, beforeEach } = require("bun:test")
+const { resolveCallableAgents, clearCallableAgentsCache } = require("./agent-resolver")
 const { ALLOWED_AGENTS } = require("./constants")
 
 function createMockClient(agents: Array<Record<string, unknown>>) {
@@ -33,6 +33,10 @@ function createFailingClient(error: Error = new Error("API unavailable")) {
 }
 
 describe("resolveCallableAgents", () => {
+  beforeEach(() => {
+    clearCallableAgentsCache()
+  })
+
   describe("#given the SDK returns agents successfully", () => {
     describe("#when only built-in agents exist", () => {
       test("#then every ALLOWED_AGENT appears in the result", async () => {
diff --git a/src/tools/call-omo-agent/agent-resolver.ts b/src/tools/call-omo-agent/agent-resolver.ts
index 9f87feb79..70bc4c32f 100644
--- a/src/tools/call-omo-agent/agent-resolver.ts
+++ b/src/tools/call-omo-agent/agent-resolver.ts
@@ -8,20 +8,37 @@ type AgentInfo = {
   mode?: "subagent" | "primary" | "all";
 };
 
+const callableAgentsCache = new Map<string, { agents: string[]; timestamp: number }>();
+const CACHE_TTL_MS = 30_000;
+
+export function clearCallableAgentsCache(): void {
+  callableAgentsCache.clear();
+}
+
 /**
  * Resolves the set of callable agent names at execute-time by merging the
  * hardcoded `ALLOWED_AGENTS` with any additional agents discovered dynamically
  * via `client.app.agents()`. Custom agents loaded from registered agent
  * directories appear here alongside built-ins.
  *
+ * Results are cached per session for 30s to avoid redundant SDK IPC calls.
+ *
  * Falls back to `ALLOWED_AGENTS` alone if the dynamic lookup fails.
  *
  * @param client - The plugin client with access to the agent registry
+ * @param sessionId - Optional session ID for cache scoping
  * @returns Array of lowercase callable agent names (excludes primary-mode agents)
  */
 export async function resolveCallableAgents(
   client: PluginInput["client"],
+  sessionId?: string,
 ): Promise<string[]> {
+  const cacheKey = sessionId ?? "__default__";
+  const cached = callableAgentsCache.get(cacheKey);
+  if (cached && Date.now() - cached.timestamp < CACHE_TTL_MS) {
+    return cached.agents;
+  }
+
   try {
     const agentsResult = await client.app.agents();
     const agents = normalizeSDKResponse(agentsResult, [] as AgentInfo[], {
@@ -33,7 +50,9 @@ export async function resolveCallableAgents(
       .map((a) => a.name.trim().toLowerCase());
 
     const merged = new Set([...ALLOWED_AGENTS, ...dynamicAgents]);
-    return [...merged];
+    const result = [...merged];
+    callableAgentsCache.set(cacheKey, { agents: result, timestamp: Date.now() });
+    return result;
   } catch (error) {
     const message = error instanceof Error ? error.message : String(error);
     log(
diff --git a/src/tools/call-omo-agent/tools-edge-cases.test.ts b/src/tools/call-omo-agent/tools-edge-cases.test.ts
index 7e766c28f..9d4c546e9 100644
--- a/src/tools/call-omo-agent/tools-edge-cases.test.ts
+++ b/src/tools/call-omo-agent/tools-edge-cases.test.ts
@@ -9,6 +9,7 @@
  */
 const { describe, test, expect, mock, beforeEach } = require("bun:test")
 const { createCallOmoAgent } = require("./tools")
+const { clearCallableAgentsCache } = require("./agent-resolver")
 
 type PluginInput = { client: any; directory: string }
 
@@ -50,6 +51,7 @@ const toolCtx = {
 }
 
 beforeEach(() => {
+  clearCallableAgentsCache()
   reserveSubagentSpawnMock.mockClear()
   reserveCommitMock.mockClear()
   reserveRollbackMock.mockClear()
diff --git a/src/tools/call-omo-agent/tools.test.ts b/src/tools/call-omo-agent/tools.test.ts
index 455e2f9aa..17491cb82 100644
--- a/src/tools/call-omo-agent/tools.test.ts
+++ b/src/tools/call-omo-agent/tools.test.ts
@@ -1,5 +1,6 @@
 const { beforeEach, describe, test, expect, mock } = require("bun:test")
 const { createCallOmoAgent } = require("./tools")
+const { clearCallableAgentsCache } = require("./agent-resolver")
 
 type PluginInput = { client: any; directory: string }
 type BackgroundManager = {
@@ -72,6 +73,7 @@ const toolCtx = {
 }
 
 beforeEach(() => {
+  clearCallableAgentsCache()
   assertCanSpawnMock.mockClear()
   reserveSubagentSpawnMock.mockClear()
   reserveCommitMock.mockClear()