fix(agent): serialize runs per session

docs/configuration.md

@@ -131,6 +131,7 @@ Controls the embedded agent runtime (provider/model/thinking/verbose/timeouts).
     timeoutSeconds: 600,
     mediaMaxMb: 5,
     heartbeatMinutes: 30,
+    maxConcurrent: 3,
     bash: {
       backgroundMs: 20000,
       timeoutSec: 1800,
@@ -146,6 +147,10 @@ Controls the embedded agent runtime (provider/model/thinking/verbose/timeouts).
 - `timeoutSec`: auto-kill after this runtime (seconds, default 1800)
 - `cleanupMs`: how long to keep finished sessions in memory (ms, default 1800000)
 
+`agent.maxConcurrent` sets the maximum number of embedded agent runs that can
+execute in parallel across sessions. Each session is still serialized (one run
+per session key at a time). Default: 1.
+
 ### `models` (custom providers + base URLs)
 
 Clawdis uses the **pi-coding-agent** model catalog. You can add custom providers

docs/queue.md

@@ -5,22 +5,24 @@ read_when:
 ---
 # Command Queue (2025-11-25)
 
-We now serialize all command-based auto-replies (WhatsApp Web listener) through a tiny in-process queue to prevent multiple commands from running at once.
+We now serialize command-based auto-replies (WhatsApp Web listener) through a tiny in-process queue to prevent multiple commands from running at once, while allowing safe parallelism across sessions.
 
 ## Why
 - Some auto-reply commands are expensive (LLM calls) and can collide when multiple inbound messages arrive close together.
 - Serializing avoids competing for terminal/stdin, keeps logs readable, and reduces the chance of rate limits from upstream tools.
 
 ## How it works
-- `src/process/command-queue.ts` holds a single FIFO queue and drains it synchronously; only one task runs at a time.
-- `getReplyFromConfig` wraps command execution with `enqueueCommand(...)`, so every config-driven command reply flows through the queue automatically.
+- `src/process/command-queue.ts` holds a lane-aware FIFO queue and drains each lane synchronously.
+- `runEmbeddedPiAgent` enqueues by **session key** (lane `session:<key>`) to guarantee only one active run per session.
+- Each session run is then queued into a **global lane** (`main` by default) so overall parallelism is capped by `agent.maxConcurrent`.
 - When verbose logging is enabled, queued commands emit a short notice if they waited more than ~2s before starting.
 - Typing indicators (`onReplyStart`) still fire immediately on enqueue so user experience is unchanged while we wait our turn.
 
 ## Scope and guarantees
 - Applies only to config-driven command replies; plain text replies are unaffected.
-- Default lane (`main`) is process-wide for inbound + main heartbeats to keep the primary workflow serialized.
+- Default lane (`main`) is process-wide for inbound + main heartbeats; set `agent.maxConcurrent` to allow multiple sessions in parallel.
 - Additional lanes may exist (e.g. `cron`) so background jobs can run in parallel without blocking inbound replies.
+- Per-session lanes guarantee that only one agent run touches a given session at a time.
 - No external dependencies or background worker threads; pure TypeScript + promises.
 
 ## Troubleshooting

src/agents/pi-embedded-runner.ts

@@ -25,7 +25,10 @@ import { formatToolAggregate } from "../auto-reply/tool-meta.js";
 import type { ClawdisConfig } from "../config/config.js";
 import { getMachineDisplayName } from "../infra/machine-name.js";
 import { splitMediaFromOutput } from "../media/parse.js";
-import { enqueueCommand } from "../process/command-queue.js";
+import {
+  enqueueCommand,
+  enqueueCommandInLane,
+} from "../process/command-queue.js";
 import { CONFIG_DIR, resolveUserPath } from "../utils.js";
 import { resolveClawdisAgentDir } from "./agent-paths.js";
 import { DEFAULT_MODEL, DEFAULT_PROVIDER } from "./defaults.js";
@@ -90,6 +93,16 @@ const DEFAULT_OAUTH_DIR = path.join(CONFIG_DIR, "credentials");
 let oauthStorageConfigured = false;
 let cachedDefaultApiKey: ReturnType<typeof defaultGetApiKey> | null = null;
 
+function resolveSessionLane(key: string) {
+  const cleaned = key.trim() || "main";
+  return cleaned.startsWith("session:") ? cleaned : `session:${cleaned}`;
+}
+
+function resolveGlobalLane(lane?: string) {
+  const cleaned = lane?.trim();
+  return cleaned ? cleaned : "main";
+}
+
 function resolveClawdisOAuthPath(): string {
   const overrideDir =
     process.env.CLAWDIS_OAUTH_DIR?.trim() || DEFAULT_OAUTH_DIR;
@@ -242,6 +255,7 @@ function resolvePromptSkills(
 
 export async function runEmbeddedPiAgent(params: {
   sessionId: string;
+  sessionKey?: string;
   sessionFile: string;
   workspaceDir: string;
   config?: ClawdisConfig;
@@ -267,13 +281,21 @@ export async function runEmbeddedPiAgent(params: {
     stream: string;
     data: Record<string, unknown>;
   }) => void;
+  lane?: string;
   enqueue?: typeof enqueueCommand;
   extraSystemPrompt?: string;
   ownerNumbers?: string[];
   enforceFinalTag?: boolean;
 }): Promise<EmbeddedPiRunResult> {
-  const enqueue = params.enqueue ?? enqueueCommand;
-  return enqueue(async () => {
+  const sessionLane = resolveSessionLane(
+    params.sessionKey?.trim() || params.sessionId,
+  );
+  const globalLane = resolveGlobalLane(params.lane);
+  const enqueueGlobal =
+    params.enqueue ??
+    ((task, opts) => enqueueCommandInLane(globalLane, task, opts));
+  return enqueueCommandInLane(sessionLane, () =>
+    enqueueGlobal(async () => {
       const started = Date.now();
       const resolvedWorkspace = resolveUserPath(params.workspaceDir);
       const prevCwd = process.cwd();
@@ -530,5 +552,6 @@ export async function runEmbeddedPiAgent(params: {
         restoreSkillEnv?.();
         process.chdir(prevCwd);
       }
-  });
+    }),
+  );
 }

src/auto-reply/reply.ts

@@ -983,6 +983,7 @@ export async function getReplyFromConfig(
     const runId = crypto.randomUUID();
     const runResult = await runEmbeddedPiAgent({
       sessionId: sessionIdFinal,
+      sessionKey,
       sessionFile,
       workspaceDir,
       config: cfg,

src/commands/agent.ts

@@ -313,6 +313,7 @@ export async function agentCommand(
   try {
     result = await runEmbeddedPiAgent({
       sessionId,
+      sessionKey,
       sessionFile,
       workspaceDir,
       config: cfg,

src/cron/isolated-agent.ts

@@ -146,7 +146,6 @@ export async function runCronIsolatedAgentTurn(params: {
   lane?: string;
 }): Promise<RunCronAgentTurnResult> {
   const agentCfg = params.cfg.agent;
-  void params.lane;
   const workspaceDirRaw =
     params.cfg.agent?.workspace ?? DEFAULT_AGENT_WORKSPACE_DIR;
   const workspace = await ensureAgentWorkspace({
@@ -236,11 +235,13 @@ export async function runCronIsolatedAgentTurn(params: {
     );
     runResult = await runEmbeddedPiAgent({
       sessionId: cronSession.sessionEntry.sessionId,
+      sessionKey: params.sessionKey,
       sessionFile,
       workspaceDir,
       config: params.cfg,
       skillsSnapshot,
       prompt: commandBody,
+      lane: params.lane ?? "cron",
       provider,
       model,
       thinkLevel,