feat: restore LETTA_SDK_TOOLS=off as listen-only mode

off now means "no client-side tools" — Sub still receives transcripts
via the SDK transport but can only use memory operations. Useful for
listen-only agents that observe without filesystem access.

Written by Cameron ◯ Letta Code

"Listening is an art that requires attention over talent." - Dean Jackson

README.md

@@ -111,7 +111,7 @@ export LETTA_BASE_URL="http://localhost:8283"  # For self-hosted Letta
 export LETTA_MODEL="anthropic/claude-sonnet-4-5"  # Model override
 export LETTA_CONTEXT_WINDOW="1048576"             # Context window size (e.g. 1M tokens)
 export LETTA_HOME="$HOME"      # Consolidate .letta state to ~/.letta/
-export LETTA_SDK_TOOLS="read-only"       # Or "full"
+export LETTA_SDK_TOOLS="read-only"       # Or "full", "off"
 ```
 
 - `LETTA_MODE` - Controls what gets injected. `whisper` (default, messages only), `full` (blocks + messages), `off` (disable). See [Modes](#modes).
@@ -120,7 +120,7 @@ export LETTA_SDK_TOOLS="read-only"       # Or "full"
 - `LETTA_MODEL` - Override the agent's model. Optional - the plugin auto-detects and selects from available models. See [Model Configuration](#model-configuration) below.
 - `LETTA_CONTEXT_WINDOW` - Override the agent's context window size (in tokens). Useful when `LETTA_MODEL` is set to a model with a large context window that differs from the server default. Example: `1048576` for 1M tokens.
 - `LETTA_HOME` - Base directory for plugin state files. Creates `{LETTA_HOME}/.letta/claude/` for session data and conversation mappings. Defaults to current working directory. Set to `$HOME` to consolidate all state in one location.
-- `LETTA_SDK_TOOLS` - Controls client-side tool access for the Subconscious agent. `read-only` (default) or `full`. See [SDK Tools](#sdk-tools).
+- `LETTA_SDK_TOOLS` - Controls client-side tool access for the Subconscious agent. `read-only` (default), `full`, or `off`. See [SDK Tools](#sdk-tools).
 
 ### Modes
 
@@ -288,6 +288,7 @@ By default, the Subconscious agent now gets **client-side tool access** via the
 |------|----------------|----------|
 | `read-only` (default) | `Read`, `Grep`, `Glob`, `web_search`, `fetch_webpage` | Safe background research and file reading |
 | `full` | All tools (Bash, Edit, Write, etc.) | Full autonomy — Sub can make changes |
+| `off` | None (memory-only) | Listen-only — Sub processes transcripts but has no client-side tools |
 
 > **Note:** Requires `@letta-ai/letta-code-sdk` (installed as a dependency).
 

scripts/conversation_utils.ts

@@ -63,7 +63,7 @@ export function getTempStateDir(): string {
 // SDK Tools Configuration
 // ============================================
 
-export type SdkToolsMode = 'read-only' | 'full';
+export type SdkToolsMode = 'read-only' | 'full' | 'off';
 
 /** Read-only tool set: safe defaults for background Sub execution */
 export const SDK_TOOLS_READ_ONLY = ['Read', 'Grep', 'Glob', 'web_search', 'fetch_webpage'];
@@ -75,10 +75,11 @@ export const SDK_TOOLS_BLOCKED = ['AskUserQuestion', 'EnterPlanMode', 'ExitPlanM
  * Get the SDK tools mode from LETTA_SDK_TOOLS env var.
  * - read-only (default): Sub can read files and search the web
  * - full: Sub has full tool access (use with caution)
+ * - off: No client-side tools (listen-only, memory operations only)
  */
 export function getSdkToolsMode(): SdkToolsMode {
   const mode = process.env.LETTA_SDK_TOOLS?.toLowerCase();
-  if (mode === 'full') return mode;
+  if (mode === 'full' || mode === 'off') return mode;
   return 'read-only';
 }
 

scripts/send_worker_sdk.ts

@@ -56,15 +56,19 @@ async function sendViaSdk(payload: SdkPayload): Promise<boolean> {
     sleeptime: { trigger: 'off' }, // don't recurse sleeptime
   };
 
-  if (payload.sdkToolsMode === 'read-only') {
+  if (payload.sdkToolsMode === 'off') {
+    // Listen-only: block all client-side tools, Sub can only use memory operations
+    sessionOptions.disallowedTools = [...blockedTools, ...readOnlyTools, 'Bash', 'Edit', 'Write', 'Task', 'Glob', 'Grep', 'Read'];
+  } else if (payload.sdkToolsMode === 'read-only') {
     sessionOptions.allowedTools = readOnlyTools;
   }
   // 'full' mode: no allowedTools restriction (all tools available)
 
+  const toolsLabel = payload.sdkToolsMode === 'off' ? 'none' : payload.sdkToolsMode === 'read-only' ? readOnlyTools.join(', ') : 'all';
   log(`Creating SDK session for conversation ${payload.conversationId} (mode: ${payload.sdkToolsMode})`);
   log(`  agent: ${payload.agentId}`);
   log(`  cwd: ${payload.cwd}`);
-  log(`  allowedTools: ${payload.sdkToolsMode === 'read-only' ? readOnlyTools.join(', ') : 'all'}`);
+  log(`  allowedTools: ${toolsLabel}`);
 
   const session = resumeSession(payload.conversationId, sessionOptions);