diff --git a/plugin/index.ts b/plugin/index.ts
index e13d0f9..8d8ec13 100644
--- a/plugin/index.ts
+++ b/plugin/index.ts
@@ -12,6 +12,13 @@ import {
   queueDynamicTrim,
   drainTrimQueueForSession,
 } from './tools/session-rewrite.js';
+import {
+  installGlobalApi as installPaddedGlobalApi,
+  createListToolsTool,
+  createSearchToolsTool,
+  createCacheToolsTool,
+  createEvictToolsTool,
+} from './tools/dynamic-tools-cache.js';
 import {
   safeRestart,
   createSafeRestartTool,
@@ -51,6 +58,12 @@ function register(api: OpenClawPluginApi): void {
 
   logger.info('PaddedCell plugin initializing...');
 
+  // Install globalThis.__padded EARLY so other plugins loaded after
+  // PaddedCell can register catalog entries / query allowTool. Plugins
+  // loaded BEFORE PaddedCell can pre-fill _pendingCatalog on a stub;
+  // installGlobalApi drains it.
+  installPaddedGlobalApi();
+
   const pluginConfig = getPluginConfig(api);
   const openclawPath = resolveOpenclawPath(pluginConfig as { openclawProfilePath?: string });
   const proxyAllowlist = resolveProxyAllowlist(pluginConfig as { proxyAllowlist?: unknown; 'proxy-allowlist'?: unknown });
@@ -241,6 +254,27 @@ function register(api: OpenClawPluginApi): void {
     } as any;
   });
 
+  // dynamic-{list,search,cache,evict}-tools — per-session tools-cache
+  // family (cross-runtime alignment with Plexum decision #37). All four
+  // are essentials (always exposed). The cache they manage gates other
+  // opt-in plugins via globalThis.__padded.allowTool — see
+  // tools/dynamic-tools-cache.ts and plans/OPENCLAW_TOOLS_FILTER_HOOK.md.
+  const cacheToolFactories = [
+    createListToolsTool,
+    createSearchToolsTool,
+    createCacheToolsTool,
+    createEvictToolsTool,
+  ];
+  for (const make of cacheToolFactories) {
+    api.registerTool((ctx) => {
+      const tool = make();
+      const inner = tool.execute;
+      tool.execute = async (callId: string, params: any) =>
+        inner(callId, params, { agentId: ctx.agentId, sessionId: ctx.sessionId });
+      return tool;
+    });
+  }
+
   // Register /ego-mgr slash command if the host exposes the (non-standard) hook.
   // This API is not part of the current OpenClawPluginApi surface; the guard
   // makes the plugin a no-op for slash commands when the host doesn't support
diff --git a/plugin/openclaw.plugin.json b/plugin/openclaw.plugin.json
index bfd460e..b18c8ff 100644
--- a/plugin/openclaw.plugin.json
+++ b/plugin/openclaw.plugin.json
@@ -10,7 +10,11 @@
       "pcexec",
       "proxy-pcexec",
       "safe_restart",
-      "dynamic-trim"
+      "dynamic-trim",
+      "dynamic-list-tools",
+      "dynamic-search-tools",
+      "dynamic-cache-tools",
+      "dynamic-evict-tools"
     ]
   },
   "configSchema": {
diff --git a/plugin/tools/dynamic-tools-cache.ts b/plugin/tools/dynamic-tools-cache.ts
new file mode 100644
index 0000000..8522bf6
--- /dev/null
+++ b/plugin/tools/dynamic-tools-cache.ts
@@ -0,0 +1,403 @@
+// `dynamic-list-tools` / `dynamic-search-tools` / `dynamic-cache-tools` /
+// `dynamic-evict-tools` — agent-driven per-session tool visibility gate.
+//
+// openclaw plugin SDK has no `before_outgoing_tools` hook (see PaddedCell
+// plans/OPENCLAW_TOOLS_FILTER_HOOK.md for the gap analysis), so this
+// implementation relies on a per-plugin opt-in pattern via the global
+// __padded API:
+//
+//   - PaddedCell exposes:
+//       globalThis.__padded.registerCatalogEntry(name, description)
+//       globalThis.__padded.allowTool(name, ctx) => boolean
+//   - Other Hangman-Lab plugins wrap their tool factories:
+//       api.registerTool((ctx) => {
+//         if (!globalThis.__padded?.allowTool?.(NAME, ctx)) return null;
+//         return realTool;
+//       });
+//     and at init:
+//       globalThis.__padded?.registerCatalogEntry?.(NAME, DESC);
+//
+// Built-in openclaw tools (read/edit/grep/bash) and plugins that don't
+// opt in to the gate are always-on. The 4 tools below are themselves
+// always-on (essentials, hardcoded). Per-session cache state lives at
+// <openclaw>/agents/<agentId>/sessions/<sessionId>/dynamic-tools-cache.json.
+//
+// Cross-runtime aligned with Plexum's decision #37 family — same tool
+// names, same input schemas, same takes-effect-next-turn semantics.
+
+import * as fs from 'node:fs';
+import * as os from 'node:os';
+import * as path from 'node:path';
+
+/** Names of tools always exposed (the 4 cache tools themselves). */
+export const ESSENTIAL_CACHE_TOOLS = new Set([
+  'dynamic-list-tools',
+  'dynamic-search-tools',
+  'dynamic-cache-tools',
+  'dynamic-evict-tools',
+]);
+
+/** Catalog entry registered by an opt-in plugin. */
+export interface CatalogEntry {
+  name: string;
+  description: string;
+}
+
+interface CacheFileShape {
+  version: number;
+  cached: Array<{ name: string; added_at_turn: number }>;
+}
+
+const CACHE_FILE_NAME = 'dynamic-tools-cache.json';
+
+function openclawRoot(): string {
+  const env = process.env.OPENCLAW_PATH;
+  if (env) return env;
+  const home = process.env.HOME || os.homedir();
+  return path.join(home, '.openclaw');
+}
+
+function cacheFilePath(agentId: string | undefined, sessionId: string | undefined): string | null {
+  if (!agentId || !sessionId) return null;
+  return path.join(openclawRoot(), 'agents', agentId, 'sessions', sessionId, CACHE_FILE_NAME);
+}
+
+function readCache(filePath: string): CacheFileShape {
+  try {
+    const raw = fs.readFileSync(filePath, 'utf8');
+    if (!raw) return { version: 1, cached: [] };
+    const parsed = JSON.parse(raw) as Partial<CacheFileShape>;
+    return { version: parsed.version ?? 1, cached: parsed.cached ?? [] };
+  } catch (err: unknown) {
+    if ((err as NodeJS.ErrnoException).code === 'ENOENT') {
+      return { version: 1, cached: [] };
+    }
+    throw err;
+  }
+}
+
+function writeCache(filePath: string, data: CacheFileShape): void {
+  fs.mkdirSync(path.dirname(filePath), { recursive: true });
+  const tmp = `${filePath}.tmp`;
+  fs.writeFileSync(tmp, JSON.stringify(data, null, 2), { mode: 0o600 });
+  fs.renameSync(tmp, filePath);
+}
+
+/** In-process catalog of opt-in plugin tools. */
+class Catalog {
+  private entries = new Map<string, string>();
+
+  register(name: string, description: string): void {
+    if (!name) return;
+    this.entries.set(name, description ?? '');
+  }
+
+  has(name: string): boolean {
+    return this.entries.has(name);
+  }
+
+  list(): CatalogEntry[] {
+    return Array.from(this.entries, ([name, description]) => ({ name, description }));
+  }
+
+  search(query: string): CatalogEntry[] {
+    const q = query.toLowerCase().trim();
+    if (!q) return [];
+    return this.list().filter(
+      (e) => e.name.toLowerCase().includes(q) || e.description.toLowerCase().includes(q),
+    );
+  }
+}
+
+const catalog = new Catalog();
+
+/**
+ * Drain any catalog entries that were queued before PaddedCell finished
+ * initializing. The buffer-drain pattern lets other plugins call
+ * `globalThis.__padded.registerCatalogEntry` at load time without
+ * worrying about load order; PaddedCell installs an early stub with
+ * `_pendingCatalog: []`, and on real init we slurp those into `catalog`.
+ */
+export function drainPendingCatalog(): number {
+  const stub = (globalThis as any).__padded;
+  if (!stub || !Array.isArray(stub._pendingCatalog)) return 0;
+  let n = 0;
+  for (const e of stub._pendingCatalog) {
+    if (e?.name) {
+      catalog.register(String(e.name), String(e.description ?? ''));
+      n++;
+    }
+  }
+  stub._pendingCatalog = [];
+  return n;
+}
+
+/**
+ * allowTool — the gate every opt-in plugin's factory queries. Returns
+ * true iff: the name is an essential cache tool, OR it's in the
+ * per-session cache file. ctx must carry agentId + sessionId (factories
+ * receive them from openclaw).
+ */
+export function allowTool(name: string, ctx: { agentId?: string; sessionId?: string }): boolean {
+  if (ESSENTIAL_CACHE_TOOLS.has(name)) return true;
+  const fp = cacheFilePath(ctx.agentId, ctx.sessionId);
+  if (!fp) return true; // no session context => can't gate, default-allow
+  try {
+    const cache = readCache(fp);
+    return cache.cached.some((e) => e.name === name);
+  } catch {
+    return true; // any read error => default-allow (don't break agent)
+  }
+}
+
+/** Install the global API onto globalThis. Idempotent — drains a pre-existing stub. */
+export function installGlobalApi(): void {
+  const existing = (globalThis as any).__padded;
+  const api = {
+    registerCatalogEntry(name: string, description: string): void {
+      catalog.register(name, description);
+    },
+    allowTool,
+    _pendingCatalog: [] as Array<{ name: string; description: string }>,
+  };
+  (globalThis as any).__padded = api;
+  if (existing?._pendingCatalog?.length) {
+    for (const e of existing._pendingCatalog) {
+      if (e?.name) catalog.register(String(e.name), String(e.description ?? ''));
+    }
+  }
+}
+
+/** Test hook — wipe catalog state between tests. */
+export function _resetCatalogForTest(): void {
+  (catalog as any).entries = new Map();
+}
+
+// ----- tool factories -----
+
+interface ToolCtx {
+  agentId?: string;
+  sessionId?: string;
+}
+
+function currentTurn(): number {
+  // openclaw plugin ctx doesn't carry turn number; record 0 as a
+  // placeholder. The field is informational (sorting / debug) — the
+  // gate semantics don't depend on it.
+  return 0;
+}
+
+function classifySource(name: string, ctx: ToolCtx): 'essentials' | 'cached' | 'available' {
+  if (ESSENTIAL_CACHE_TOOLS.has(name)) return 'essentials';
+  const fp = cacheFilePath(ctx.agentId, ctx.sessionId);
+  if (fp) {
+    try {
+      const c = readCache(fp);
+      if (c.cached.some((e) => e.name === name)) return 'cached';
+    } catch {
+      // fall through
+    }
+  }
+  return 'available';
+}
+
+function renderCatalogText(
+  entries: CatalogEntry[],
+  ctx: ToolCtx,
+  header: string,
+): string {
+  let ess = 0, cac = 0, avl = 0;
+  const tagged = entries.map((e) => {
+    const src = classifySource(e.name, ctx);
+    if (src === 'essentials') ess++;
+    else if (src === 'cached') cac++;
+    else avl++;
+    return { ...e, source: src };
+  });
+  const sourceRank = (s: string) => (s === 'essentials' ? 0 : s === 'cached' ? 1 : 2);
+  tagged.sort((a, b) => {
+    const ra = sourceRank(a.source), rb = sourceRank(b.source);
+    if (ra !== rb) return ra - rb;
+    return a.name.localeCompare(b.name);
+  });
+  const lines: string[] = [];
+  lines.push(header);
+  lines.push(`total: ${tagged.length} (essentials: ${ess}, cached: ${cac}, available: ${avl})`);
+  lines.push('');
+  for (const t of tagged) {
+    lines.push(`[${t.source}] ${t.name}`);
+    lines.push(`  ${t.description}`);
+    lines.push('');
+  }
+  return lines.join('\n');
+}
+
+export function createListToolsTool(): any {
+  return {
+    name: 'dynamic-list-tools',
+    description:
+      'List the per-session tool catalog (essentials / cached / available). Pair with dynamic-cache-tools to enable specific tools for this session. Cache takes effect next turn.',
+    parameters: { type: 'object', properties: {}, required: [] },
+    async execute(_callId: string, _params: any, ctx?: ToolCtx) {
+      const c = ctx ?? {};
+      const entries = catalog.list();
+      // Also include essential cache tools themselves so the catalog is honest
+      for (const n of ESSENTIAL_CACHE_TOOLS) {
+        if (!entries.some((e) => e.name === n)) {
+          entries.push({ name: n, description: '(PaddedCell cache control tool)' });
+        }
+      }
+      const text = renderCatalogText(
+        entries,
+        c,
+        'Call dynamic-cache-tools({names: [...]}) to make available tools usable this session.',
+      );
+      return { content: [{ type: 'text', text }] };
+    },
+  };
+}
+
+export function createSearchToolsTool(): any {
+  return {
+    name: 'dynamic-search-tools',
+    description:
+      'Substring search (case-insensitive) over tool names + descriptions. Returns matches grouped by source.',
+    parameters: {
+      type: 'object',
+      properties: { query: { type: 'string' } },
+      required: ['query'],
+    },
+    async execute(_callId: string, params: any, ctx?: ToolCtx) {
+      const c = ctx ?? {};
+      const query = String(params?.query ?? '').trim();
+      if (!query) {
+        return {
+          content: [{ type: 'text', text: 'dynamic-search-tools: query is required' }],
+          isError: true,
+        };
+      }
+      const matched = catalog.search(query);
+      const text = renderCatalogText(
+        matched,
+        c,
+        `query: "${query}" — matches: ${matched.length}`,
+      );
+      return { content: [{ type: 'text', text }] };
+    },
+  };
+}
+
+export function createCacheToolsTool(): any {
+  return {
+    name: 'dynamic-cache-tools',
+    description:
+      'Add the given tool names to this session\'s tools-cache. Takes effect starting your next turn (this iteration\'s tool list is frozen).',
+    parameters: {
+      type: 'object',
+      properties: {
+        names: { type: 'array', items: { type: 'string' } },
+      },
+      required: ['names'],
+    },
+    async execute(_callId: string, params: any, ctx?: ToolCtx) {
+      const c = ctx ?? {};
+      const names = Array.isArray(params?.names) ? params.names.map(String) : [];
+      if (names.length === 0) {
+        return {
+          content: [{ type: 'text', text: 'dynamic-cache-tools: names is required (non-empty)' }],
+          isError: true,
+        };
+      }
+      const fp = cacheFilePath(c.agentId, c.sessionId);
+      if (!fp) {
+        return {
+          content: [{ type: 'text', text: 'dynamic-cache-tools: no session context' }],
+          isError: true,
+        };
+      }
+      const cache = readCache(fp);
+      const known = new Set(catalog.list().map((e) => e.name));
+      // Essentials are always allowed; recognize them as "known" too.
+      for (const n of ESSENTIAL_CACHE_TOOLS) known.add(n);
+      const added: string[] = [];
+      const alreadyCached: string[] = [];
+      const unknown: string[] = [];
+      const turn = currentTurn();
+      for (const n of names) {
+        if (!known.has(n)) {
+          unknown.push(n);
+          continue;
+        }
+        if (cache.cached.some((e) => e.name === n)) {
+          alreadyCached.push(n);
+          continue;
+        }
+        cache.cached.push({ name: n, added_at_turn: turn });
+        added.push(n);
+      }
+      writeCache(fp, cache);
+      const result = {
+        added,
+        already_cached: alreadyCached,
+        unknown,
+        note: 'Newly cached tools are available starting your next turn.',
+      };
+      return { content: [{ type: 'text', text: JSON.stringify(result) }] };
+    },
+  };
+}
+
+export function createEvictToolsTool(): any {
+  return {
+    name: 'dynamic-evict-tools',
+    description:
+      'Remove the given tool names from this session\'s tools-cache. Essentials are silently un-evictable. Takes effect starting your next turn.',
+    parameters: {
+      type: 'object',
+      properties: {
+        names: { type: 'array', items: { type: 'string' } },
+      },
+      required: ['names'],
+    },
+    async execute(_callId: string, params: any, ctx?: ToolCtx) {
+      const c = ctx ?? {};
+      const names = Array.isArray(params?.names) ? params.names.map(String) : [];
+      if (names.length === 0) {
+        return {
+          content: [{ type: 'text', text: 'dynamic-evict-tools: names is required (non-empty)' }],
+          isError: true,
+        };
+      }
+      const fp = cacheFilePath(c.agentId, c.sessionId);
+      if (!fp) {
+        return {
+          content: [{ type: 'text', text: 'dynamic-evict-tools: no session context' }],
+          isError: true,
+        };
+      }
+      const cache = readCache(fp);
+      const evicted: string[] = [];
+      const notCached: string[] = [];
+      for (const n of names) {
+        if (ESSENTIAL_CACHE_TOOLS.has(n)) {
+          notCached.push(n);
+          continue;
+        }
+        const idx = cache.cached.findIndex((e) => e.name === n);
+        if (idx < 0) {
+          notCached.push(n);
+          continue;
+        }
+        cache.cached.splice(idx, 1);
+        evicted.push(n);
+      }
+      writeCache(fp, cache);
+      const result = {
+        evicted,
+        not_cached: notCached,
+        note: 'Evictions take effect starting your next turn.',
+      };
+      return { content: [{ type: 'text', text: JSON.stringify(result) }] };
+    },
+  };
+}