diff --git a/src/gateway/server-bridge.ts b/src/gateway/server-bridge.ts
index b2df674e6..85147d62e 100644
--- a/src/gateway/server-bridge.ts
+++ b/src/gateway/server-bridge.ts
@@ -80,6 +80,7 @@ import {
   type SessionsPatchResult,
 } from "./session-utils.js";
 import { applySessionsPatchToStore } from "./sessions-patch.js";
+import { resolveSessionKeyFromResolveParams } from "./sessions-resolve.js";
 import { formatForLog } from "./ws-log.js";
 
 export type BridgeHandlersContext = {
@@ -314,93 +315,20 @@ export function createBridgeHandlers(ctx: BridgeHandlersContext) {
 
           const p = params as SessionsResolveParams;
           const cfg = loadConfig();
-
-          const key = typeof p.key === "string" ? p.key.trim() : "";
-          const label = typeof p.label === "string" ? p.label.trim() : "";
-          const hasKey = key.length > 0;
-          const hasLabel = label.length > 0;
-          if (hasKey && hasLabel) {
+          const resolved = resolveSessionKeyFromResolveParams({ cfg, p });
+          if (!resolved.ok) {
             return {
               ok: false,
               error: {
-                code: ErrorCodes.INVALID_REQUEST,
-                message: "Provide either key or label (not both)",
-              },
-            };
-          }
-          if (!hasKey && !hasLabel) {
-            return {
-              ok: false,
-              error: {
-                code: ErrorCodes.INVALID_REQUEST,
-                message: "Either key or label is required",
-              },
-            };
-          }
-
-          if (hasKey) {
-            const target = resolveGatewaySessionStoreTarget({ cfg, key });
-            const store = loadSessionStore(target.storePath);
-            const existingKey = target.storeKeys.find(
-              (candidate) => store[candidate],
-            );
-            if (!existingKey) {
-              return {
-                ok: false,
-                error: {
-                  code: ErrorCodes.INVALID_REQUEST,
-                  message: `No session found: ${key}`,
-                },
-              };
-            }
-            return {
-              ok: true,
-              payloadJSON: JSON.stringify({
-                ok: true,
-                key: target.canonicalKey,
-              }),
-            };
-          }
-
-          const { storePath, store } = loadCombinedSessionStoreForGateway(cfg);
-          const list = listSessionsFromStore({
-            cfg,
-            storePath,
-            store,
-            opts: {
-              includeGlobal: p.includeGlobal === true,
-              includeUnknown: p.includeUnknown === true,
-              label,
-              agentId: p.agentId,
-              spawnedBy: p.spawnedBy,
-              limit: 2,
-            },
-          });
-          if (list.sessions.length === 0) {
-            return {
-              ok: false,
-              error: {
-                code: ErrorCodes.INVALID_REQUEST,
-                message: `No session found with label: ${label}`,
-              },
-            };
-          }
-          if (list.sessions.length > 1) {
-            const keys = list.sessions.map((s) => s.key).join(", ");
-            return {
-              ok: false,
-              error: {
-                code: ErrorCodes.INVALID_REQUEST,
-                message: `Multiple sessions found with label: ${label} (${keys})`,
+                code: resolved.error.code,
+                message: resolved.error.message,
+                details: resolved.error.details,
               },
             };
           }
           return {
             ok: true,
-            payloadJSON: JSON.stringify({
-              ok: true,
-              key: list.sessions[0]?.key,
-            }),
+            payloadJSON: JSON.stringify({ ok: true, key: resolved.key }),
           };
         }
         case "sessions.patch": {
diff --git a/src/gateway/server-methods/sessions.ts b/src/gateway/server-methods/sessions.ts
index ffde2e839..ba95cb1e9 100644
--- a/src/gateway/server-methods/sessions.ts
+++ b/src/gateway/server-methods/sessions.ts
@@ -35,6 +35,7 @@ import {
   type SessionsPatchResult,
 } from "../session-utils.js";
 import { applySessionsPatchToStore } from "../sessions-patch.js";
+import { resolveSessionKeyFromResolveParams } from "../sessions-resolve.js";
 import type { GatewayRequestHandlers } from "./types.js";
 
 export const sessionsHandlers: GatewayRequestHandlers = {
@@ -76,106 +77,12 @@ export const sessionsHandlers: GatewayRequestHandlers = {
     const p = params as import("../protocol/index.js").SessionsResolveParams;
     const cfg = loadConfig();
 
-    const key = typeof p.key === "string" ? p.key.trim() : "";
-    const label = typeof p.label === "string" ? p.label.trim() : "";
-    const hasKey = key.length > 0;
-    const hasLabel = label.length > 0;
-    if (hasKey && hasLabel) {
-      respond(
-        false,
-        undefined,
-        errorShape(
-          ErrorCodes.INVALID_REQUEST,
-          "Provide either key or label (not both)",
-        ),
-      );
+    const resolved = resolveSessionKeyFromResolveParams({ cfg, p });
+    if (!resolved.ok) {
+      respond(false, undefined, resolved.error);
       return;
     }
-    if (!hasKey && !hasLabel) {
-      respond(
-        false,
-        undefined,
-        errorShape(
-          ErrorCodes.INVALID_REQUEST,
-          "Either key or label is required",
-        ),
-      );
-      return;
-    }
-
-    if (hasKey) {
-      if (!key) {
-        respond(
-          false,
-          undefined,
-          errorShape(ErrorCodes.INVALID_REQUEST, "key required"),
-        );
-        return;
-      }
-      const target = resolveGatewaySessionStoreTarget({ cfg, key });
-      const store = loadSessionStore(target.storePath);
-      const existingKey = target.storeKeys.find(
-        (candidate) => store[candidate],
-      );
-      if (!existingKey) {
-        respond(
-          false,
-          undefined,
-          errorShape(ErrorCodes.INVALID_REQUEST, `No session found: ${key}`),
-        );
-        return;
-      }
-      respond(true, { ok: true, key: target.canonicalKey }, undefined);
-      return;
-    }
-
-    if (!label) {
-      respond(
-        false,
-        undefined,
-        errorShape(ErrorCodes.INVALID_REQUEST, "label required"),
-      );
-      return;
-    }
-
-    const { storePath, store } = loadCombinedSessionStoreForGateway(cfg);
-    const list = listSessionsFromStore({
-      cfg,
-      storePath,
-      store,
-      opts: {
-        includeGlobal: p.includeGlobal === true,
-        includeUnknown: p.includeUnknown === true,
-        label,
-        agentId: p.agentId,
-        spawnedBy: p.spawnedBy,
-        limit: 2,
-      },
-    });
-    if (list.sessions.length === 0) {
-      respond(
-        false,
-        undefined,
-        errorShape(
-          ErrorCodes.INVALID_REQUEST,
-          `No session found with label: ${label}`,
-        ),
-      );
-      return;
-    }
-    if (list.sessions.length > 1) {
-      const keys = list.sessions.map((s) => s.key).join(", ");
-      respond(
-        false,
-        undefined,
-        errorShape(
-          ErrorCodes.INVALID_REQUEST,
-          `Multiple sessions found with label: ${label} (${keys})`,
-        ),
-      );
-      return;
-    }
-    respond(true, { ok: true, key: list.sessions[0]?.key }, undefined);
+    respond(true, { ok: true, key: resolved.key }, undefined);
   },
   "sessions.patch": async ({ params, respond, context }) => {
     if (!validateSessionsPatchParams(params)) {
diff --git a/src/gateway/sessions-resolve.ts b/src/gateway/sessions-resolve.ts
new file mode 100644
index 000000000..5f6fa05b7
--- /dev/null
+++ b/src/gateway/sessions-resolve.ts
@@ -0,0 +1,107 @@
+import type { ClawdbotConfig } from "../config/config.js";
+import { loadSessionStore } from "../config/sessions.js";
+import { parseSessionLabel } from "../sessions/session-label.js";
+import {
+  ErrorCodes,
+  type ErrorShape,
+  errorShape,
+  type SessionsResolveParams,
+} from "./protocol/index.js";
+import {
+  listSessionsFromStore,
+  loadCombinedSessionStoreForGateway,
+  resolveGatewaySessionStoreTarget,
+} from "./session-utils.js";
+
+export type SessionsResolveResult =
+  | { ok: true; key: string }
+  | { ok: false; error: ErrorShape };
+
+export function resolveSessionKeyFromResolveParams(params: {
+  cfg: ClawdbotConfig;
+  p: SessionsResolveParams;
+}): SessionsResolveResult {
+  const { cfg, p } = params;
+
+  const key = typeof p.key === "string" ? p.key.trim() : "";
+  const hasKey = key.length > 0;
+  const hasLabel = typeof p.label === "string" && p.label.trim().length > 0;
+  if (hasKey && hasLabel) {
+    return {
+      ok: false,
+      error: errorShape(
+        ErrorCodes.INVALID_REQUEST,
+        "Provide either key or label (not both)",
+      ),
+    };
+  }
+  if (!hasKey && !hasLabel) {
+    return {
+      ok: false,
+      error: errorShape(
+        ErrorCodes.INVALID_REQUEST,
+        "Either key or label is required",
+      ),
+    };
+  }
+
+  if (hasKey) {
+    const target = resolveGatewaySessionStoreTarget({ cfg, key });
+    const store = loadSessionStore(target.storePath);
+    const existingKey = target.storeKeys.find((candidate) => store[candidate]);
+    if (!existingKey) {
+      return {
+        ok: false,
+        error: errorShape(
+          ErrorCodes.INVALID_REQUEST,
+          `No session found: ${key}`,
+        ),
+      };
+    }
+    return { ok: true, key: target.canonicalKey };
+  }
+
+  const parsedLabel = parseSessionLabel(p.label);
+  if (!parsedLabel.ok) {
+    return {
+      ok: false,
+      error: errorShape(ErrorCodes.INVALID_REQUEST, parsedLabel.error),
+    };
+  }
+
+  const { storePath, store } = loadCombinedSessionStoreForGateway(cfg);
+  const list = listSessionsFromStore({
+    cfg,
+    storePath,
+    store,
+    opts: {
+      includeGlobal: p.includeGlobal === true,
+      includeUnknown: p.includeUnknown === true,
+      label: parsedLabel.label,
+      agentId: p.agentId,
+      spawnedBy: p.spawnedBy,
+      limit: 2,
+    },
+  });
+  if (list.sessions.length === 0) {
+    return {
+      ok: false,
+      error: errorShape(
+        ErrorCodes.INVALID_REQUEST,
+        `No session found with label: ${parsedLabel.label}`,
+      ),
+    };
+  }
+  if (list.sessions.length > 1) {
+    const keys = list.sessions.map((s) => s.key).join(", ");
+    return {
+      ok: false,
+      error: errorShape(
+        ErrorCodes.INVALID_REQUEST,
+        `Multiple sessions found with label: ${parsedLabel.label} (${keys})`,
+      ),
+    };
+  }
+
+  return { ok: true, key: String(list.sessions[0]?.key ?? "") };
+}