feat: remove default per-turn step limit of 1000

.changeset/unlimited-max-steps-per-turn.md

@@ -0,0 +1,6 @@
+---
+"@moonshot-ai/agent-core": minor
+"@moonshot-ai/kimi-code": minor
+---
+
+Remove the default per-turn step limit of 1000. Users can still set `max_steps_per_turn` in config to enforce a custom limit.

docs/en/configuration/config-files.md

@@ -62,7 +62,6 @@ max_context_size = 262144
 mode = "auto"
 
 [loop_control]
-max_steps_per_turn = 1000
 max_retries_per_step = 3
 reserved_context_size = 50000
 
@@ -154,7 +153,7 @@ max_context_size = 1047576
 
 | Field | Type | Default | Description |
 | --- | --- | --- | --- |
-| `max_steps_per_turn` | `integer` | `1000` | Maximum number of steps per turn |
+| `max_steps_per_turn` | `integer` | — | Maximum number of steps per turn; set to `0` or leave unset for unlimited. Setting `0` is useful for overriding a previously configured limit. |
 | `max_retries_per_step` | `integer` | `3` | Maximum retries per step |
 | `reserved_context_size` | `integer` | — | Number of tokens reserved for response generation; compaction is triggered when the context approaches this threshold |
 

docs/zh/configuration/config-files.md

@@ -62,7 +62,6 @@ max_context_size = 262144
 mode = "auto"
 
 [loop_control]
-max_steps_per_turn = 1000
 max_retries_per_step = 3
 reserved_context_size = 50000
 
@@ -154,7 +153,7 @@ max_context_size = 1047576
 
 | 字段 | 类型 | 默认值 | 说明 |
 | --- | --- | --- | --- |
-| `max_steps_per_turn` | `integer` | `1000` | 单轮最大步数 |
+| `max_steps_per_turn` | `integer` | — | 单轮最大步数；不设置或设为 `0` 则无上限。设为 `0` 可用于显式覆盖此前已配置的限制。 |
 | `max_retries_per_step` | `integer` | `3` | 单步最大重试次数 |
 | `reserved_context_size` | `integer` | — | 预留给响应生成的 token 数；上下文逼近该阈值时触发压缩 |
 

packages/agent-core/src/config/schema.ts

@@ -80,7 +80,7 @@ export const PermissionConfigSchema = z.object({
 export type PermissionConfig = z.infer<typeof PermissionConfigSchema>;
 
 export const LoopControlSchema = z.object({
-  maxStepsPerTurn: z.number().int().min(1).optional(),
+  maxStepsPerTurn: z.number().int().min(0).optional(),
   maxRetriesPerStep: z.number().int().min(0).optional(),
   maxRalphIterations: z.number().int().min(-1).optional(),
   reservedContextSize: z.number().int().min(0).optional(),

packages/agent-core/src/loop/run-turn.ts

@@ -28,8 +28,6 @@ import type {
   TurnResult,
 } from './types';
 
-const DEFAULT_MAX_STEPS = 1000;
-
 export interface RunTurnInput {
   readonly turnId: string;
   readonly signal: AbortSignal;
@@ -53,7 +51,7 @@ export async function runTurn(input: RunTurnInput): Promise<TurnResult> {
     tools,
     hooks,
     log,
-    maxSteps = DEFAULT_MAX_STEPS,
+    maxSteps,
     maxRetryAttempts,
   } = input;
   let usage: TokenUsage = emptyUsage();
@@ -69,7 +67,7 @@ export async function runTurn(input: RunTurnInput): Promise<TurnResult> {
     while (true) {
       signal.throwIfAborted();
 
-      if (steps >= maxSteps) {
+      if (maxSteps !== undefined && maxSteps > 0 && steps >= maxSteps) {
         throw createMaxStepsExceededError(maxSteps);
       }
 

packages/agent-core/test/loop/turn-lifecycle.e2e.test.ts

@@ -166,37 +166,47 @@ describe('runTurn — turn lifecycle', () => {
     expect(interruptedTypes).toContain('max_steps');
   });
 
-  it('throws immediately when maxSteps=0 (boundary)', async () => {
-    const { error, sink, llm, context } = await runTurnExpectingThrow({
+  it('does not enforce a max step limit when maxSteps is 0', async () => {
+    const echo = new EchoTool();
+    const { result } = await runTurn({
       maxSteps: 0,
-      responses: [makeEndTurnResponse('never reached')],
+      tools: [echo],
+      responses: [
+        makeToolUseResponse([makeToolCall('echo', { text: '1' }, 'a')]),
+        makeToolUseResponse([makeToolCall('echo', { text: '2' }, 'b')]),
+        makeEndTurnResponse('done'),
+      ],
     });
 
-    expect(error).toBeInstanceOf(KimiError);
-    expect((error as KimiError).code).toBe(ErrorCodes.LOOP_MAX_STEPS_EXCEEDED);
-    expect(llm.callCount).toBe(0);
-    // No step envelope was opened
-    expect(context.stepBegins().length).toBe(0);
-    expect(context.stepEnds().length).toBe(0);
-    expect(sink.count('step.begin')).toBe(0);
-    // turn.interrupted is still emitted without pretending a step started.
-    const interrupted = sink.byType('turn.interrupted');
-    expect(interrupted.length).toBe(1);
-    expect(interrupted[0]?.reason).toBe('max_steps');
-    expect(interrupted[0]?.attemptedSteps).toBe(0);
-    expect(interrupted[0]?.activeStep).toBeUndefined();
+    expect(result.stopReason).toBe('end_turn');
+    expect(result.steps).toBe(3);
+    expect(echo.calls).toEqual([
+      { id: 'a', turnId: 'turn-1', args: { text: '1' } },
+      { id: 'b', turnId: 'turn-1', args: { text: '2' } },
+    ]);
   });
 
-  it('uses a generous default maxSteps when omitted', async () => {
-    // We don't want to actually exhaust the default; just prove that a
-    // single end_turn step under no explicit limit succeeds. The exact
-    // numeric default is an implementation detail, but it must allow at
-    // least one step.
+  it('does not enforce a max step limit when maxSteps is omitted', async () => {
+    const echo = new EchoTool();
     const { result } = await runTurn({
-      responses: [makeEndTurnResponse('ok')],
+      tools: [echo],
+      responses: [
+        makeToolUseResponse([makeToolCall('echo', { text: '1' }, 'a')]),
+        makeToolUseResponse([makeToolCall('echo', { text: '2' }, 'b')]),
+        makeToolUseResponse([makeToolCall('echo', { text: '3' }, 'c')]),
+        makeToolUseResponse([makeToolCall('echo', { text: '4' }, 'd')]),
+        makeEndTurnResponse('done'),
+      ],
     });
+
     expect(result.stopReason).toBe('end_turn');
-    expect(result.steps).toBe(1);
+    expect(result.steps).toBe(5);
+    expect(echo.calls).toEqual([
+      { id: 'a', turnId: 'turn-1', args: { text: '1' } },
+      { id: 'b', turnId: 'turn-1', args: { text: '2' } },
+      { id: expect.any(String), turnId: 'turn-1', args: { text: '3' } },
+      { id: expect.any(String), turnId: 'turn-1', args: { text: '4' } },
+    ]);
   });
 
   it('aggregates usage across steps including cache fields', async () => {

packages/node-sdk/examples/kimi-harness-config-smoke.ts

@@ -38,7 +38,6 @@ async function main(): Promise<void> {
       },
     },
     loopControl: {
-      maxStepsPerTurn: 1000,
       maxRetriesPerStep: 3,
       maxRalphIterations: 0,
       reservedContextSize: 50000,

packages/node-sdk/test/config.test.ts

@@ -56,7 +56,6 @@ capabilities = ["image_in", "thinking", "video_in"]
 display_name = "Kimi for Coding"
 
 [loop_control]
-max_steps_per_turn = 1000
 max_retries_per_step = 3
 max_ralph_iterations = 0
 reserved_context_size = 50000
@@ -111,7 +110,6 @@ describe('SDK config TOML', () => {
     });
 
     expect(config.loopControl).toEqual({
-      maxStepsPerTurn: 1000,
       maxRetriesPerStep: 3,
       maxRalphIterations: 0,
       reservedContextSize: 50000,