diff --git a/packages/opencode/src/cli/cmd/tui/component/dialog-session-list.tsx b/packages/opencode/src/cli/cmd/tui/component/dialog-session-list.tsx
index 5e0095a8dfef..bbb8a91e8b7d 100644
--- a/packages/opencode/src/cli/cmd/tui/component/dialog-session-list.tsx
+++ b/packages/opencode/src/cli/cmd/tui/component/dialog-session-list.tsx
@@ -24,6 +24,9 @@ export function DialogSessionList() {
 
   const options = createMemo(() => {
     const today = new Date().toDateString()
+    const sessionsListLimit = (sync.data.config.tui as any)?.session_list_limit
+    const limit = sessionsListLimit === "none" ? undefined : sessionsListLimit || 150
+
     return sync.data.session
       .filter((x) => x.parentID === undefined)
       .map((x) => {
@@ -41,7 +44,7 @@ export function DialogSessionList() {
           footer: Locale.time(x.time.updated),
         }
       })
-      .slice(0, 150)
+      .slice(0, limit)
   })
 
   createEffect(() => {
diff --git a/packages/opencode/src/cli/cmd/tui/context/sync.tsx b/packages/opencode/src/cli/cmd/tui/context/sync.tsx
index b7ef8a2214b4..f3ab41aa50b2 100644
--- a/packages/opencode/src/cli/cmd/tui/context/sync.tsx
+++ b/packages/opencode/src/cli/cmd/tui/context/sync.tsx
@@ -184,7 +184,16 @@ export const { use: useSync, provider: SyncProvider } = createSimpleContext({
             event.properties.info.sessionID,
             produce((draft) => {
               draft.splice(result.index, 0, event.properties.info)
-              if (draft.length > 100) draft.shift()
+              const maxMessages = (store.config.tui as any)?.messages_limit
+              const maxMessagesCount = maxMessages === "none" ? Infinity : maxMessages || 100
+              // DEBUG: Log message limit behavior
+              console.log(
+                `[SYNC] Session ${event.properties.info.sessionID}: messages_limit=${maxMessages}, maxMessagesCount=${maxMessagesCount}`,
+              )
+              if (draft.length > maxMessagesCount) {
+                console.log(`[SYNC] Session ${event.properties.info.sessionID}: LIMIT EXCEEDED - shifting messages`)
+                draft.shift()
+              }
             }),
           )
           break
@@ -332,9 +341,11 @@ export const { use: useSync, provider: SyncProvider } = createSimpleContext({
         },
         async sync(sessionID: string) {
           if (fullSyncedSessions.has(sessionID)) return
+          const messagesLimit = (store.config.tui as any)?.messages_limit
+          const limit = messagesLimit === "none" ? undefined : messagesLimit || 100
           const [session, messages, todo, diff] = await Promise.all([
             sdk.client.session.get({ path: { id: sessionID }, throwOnError: true }),
-            sdk.client.session.messages({ path: { id: sessionID }, query: { limit: 100 } }),
+            sdk.client.session.messages({ path: { id: sessionID }, query: { limit } }),
             sdk.client.session.todo({ path: { id: sessionID } }),
             sdk.client.session.diff({ path: { id: sessionID } }),
           ])
@@ -348,6 +359,7 @@ export const { use: useSync, provider: SyncProvider } = createSimpleContext({
               for (const message of messages.data!) {
                 draft.part[message.info.id] = message.parts
               }
+
               draft.session_diff[sessionID] = diff.data ?? []
             }),
           )
diff --git a/packages/opencode/src/config/config.ts b/packages/opencode/src/config/config.ts
index a49612090553..b5e91bbfaab4 100644
--- a/packages/opencode/src/config/config.ts
+++ b/packages/opencode/src/config/config.ts
@@ -460,7 +460,18 @@ export namespace Config {
       .enum(["auto", "stacked"])
       .optional()
       .describe("Control diff rendering style: 'auto' adapts to terminal width, 'stacked' always shows single column"),
+    session_list_limit: z
+      .union([z.number().min(1), z.literal("none")])
+      .optional()
+      .default(150)
+      .describe("Maximum number of sessions to display in session list, or 'none' to show all sessions"),
+    messages_limit: z
+      .union([z.number().min(1), z.literal("none")])
+      .optional()
+      .default(100)
+      .describe("Maximum number of message parts to load per session when syncing, or 'none' to load all messages"),
   })
+  export type TUI = z.infer<typeof TUI>
 
   export const Layout = z.enum(["auto", "stretch"]).meta({
     ref: "LayoutConfig",
diff --git a/packages/opencode/src/session/index.ts b/packages/opencode/src/session/index.ts
index f09818caa2e6..ecdd0e580ea2 100644
--- a/packages/opencode/src/session/index.ts
+++ b/packages/opencode/src/session/index.ts
@@ -291,11 +291,27 @@ export namespace Session {
     }),
     async (input) => {
       const result = [] as MessageV2.WithParts[]
+      let totalParts = 0
+
       for await (const msg of MessageV2.stream(input.sessionID)) {
-        if (input.limit && result.length >= input.limit) break
+        if (input.limit && totalParts + msg.parts.length > input.limit) {
+          // If adding this message would exceed the limit, check if we can fit a partial message
+          if (totalParts < input.limit) {
+            // We have room for some parts of this message, but this would be complex to implement
+            // For now, just break to stay within the limit
+            break
+          }
+          break
+        }
         result.push(msg)
+        totalParts += msg.parts.length
       }
       result.reverse()
+
+      // DEBUG: Log what we're returning
+      console.log(
+        `[Session.messages] Returning ${result.length} messages for session ${input.sessionID} with limit ${input.limit}`,
+      )
       return result
     },
   )
diff --git a/packages/opencode/test/config/config.test.ts b/packages/opencode/test/config/config.test.ts
index 2ff8c01cdb07..d6f0500eaa80 100644
--- a/packages/opencode/test/config/config.test.ts
+++ b/packages/opencode/test/config/config.test.ts
@@ -501,3 +501,123 @@ test("deduplicates duplicate plugins from global and local configs", async () =>
     },
   })
 })
+
+test("handles TUI configuration with session_list_limit and messages_limit", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          tui: {
+            session_list_limit: 200,
+            messages_limit: 50,
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const config = await Config.get()
+      expect(config.tui?.session_list_limit).toBe(200)
+      expect(config.tui?.messages_limit).toBe(50)
+    },
+  })
+})
+
+test("handles TUI configuration with session_list_limit set to 'none'", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          tui: {
+            session_list_limit: "none",
+            messages_limit: 75,
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const config = await Config.get()
+      expect(config.tui?.session_list_limit).toBe("none")
+      expect(config.tui?.messages_limit).toBe(75)
+    },
+  })
+})
+
+test("validates TUI session_list_limit schema - rejects invalid values", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          tui: {
+            session_list_limit: -5, // Invalid: negative number
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      await expect(Config.get()).rejects.toThrow()
+    },
+  })
+})
+
+test("validates TUI messages_limit schema - rejects invalid values", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          tui: {
+            messages_limit: 0, // Invalid: must be >= 1
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      await expect(Config.get()).rejects.toThrow()
+    },
+  })
+})
+
+test("handles partial TUI configuration with backward compatibility", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          tui: {
+            scroll_speed: 2.5,
+            // session_list_limit and messages_limit not specified - should inherit from global config
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const config = await Config.get()
+      expect(config.tui?.scroll_speed).toBe(2.5)
+      // Note: session_list_limit and messages_limit may be inherited from global config
+      // The important thing is that the config loads successfully and scroll_speed is set correctly
+    },
+  })
+})
diff --git a/packages/sdk/js/src/gen/types.gen.ts b/packages/sdk/js/src/gen/types.gen.ts
index 70fceedbcb2c..ab947702f804 100644
--- a/packages/sdk/js/src/gen/types.gen.ts
+++ b/packages/sdk/js/src/gen/types.gen.ts
@@ -1008,6 +1008,14 @@ export type Config = {
      * Control diff rendering style: 'auto' adapts to terminal width, 'stacked' always shows single column
      */
     diff_style?: "auto" | "stacked"
+    /**
+     * Maximum number of sessions to display in session list, or 'none' to show all sessions
+     */
+    session_list_limit?: number | "none"
+    /**
+     * Maximum number of messages to load per session when syncing, or 'none' to load all messages
+     */
+    messages_limit?: number | "none"
   }
   /**
    * Command configuration, see https://opencode.ai/docs/commands