From 602cec160c377c4cff4b69e2132d7810f2257c36 Mon Sep 17 00:00:00 2001
From: cyning <cyning12@gmail.com>
Date: Fri, 12 Jun 2026 14:21:46 +0800
Subject: [PATCH] fix(read): report both line and byte caps when dual limits
 hit
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Fixes #94 — finishMessage uses independent checks so MAX_LINES and
MAX_BYTES messages appear together; add regression test.

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 .changeset/fix-read-dual-limit-status.md           |  8 ++++++++
 packages/agent-core/src/tools/builtin/file/read.ts |  6 ++++--
 packages/agent-core/test/tools/read.test.ts        | 13 +++++++++++++
 3 files changed, 25 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/fix-read-dual-limit-status.md

diff --git a/.changeset/fix-read-dual-limit-status.md b/.changeset/fix-read-dual-limit-status.md
new file mode 100644
index 000000000..901e15c2e
--- /dev/null
+++ b/.changeset/fix-read-dual-limit-status.md
@@ -0,0 +1,8 @@
+---
+"@moonshot-ai/agent-core": patch
+"@moonshot-ai/kimi-code": patch
+---
+
+fix(read): report both MAX_LINES and MAX_BYTES caps when both are hit
+
+Fixes #94
diff --git a/packages/agent-core/src/tools/builtin/file/read.ts b/packages/agent-core/src/tools/builtin/file/read.ts
index e9aa6472f..c9fde6b5d 100644
--- a/packages/agent-core/src/tools/builtin/file/read.ts
+++ b/packages/agent-core/src/tools/builtin/file/read.ts
@@ -446,9 +446,11 @@ export class ReadTool implements BuiltinTool<ReadInput> {
     parts.push(`Total lines in file: ${String(input.totalLines)}.`);
     if (input.maxLinesReached) {
       parts.push(`Max ${String(MAX_LINES)} lines reached.`);
-    } else if (input.maxBytesReached) {
+    }
+    if (input.maxBytesReached) {
       parts.push(`Max ${String(MAX_BYTES)} bytes reached.`);
-    } else if (lineCount < input.requestedLines) {
+    }
+    if (!input.maxLinesReached && !input.maxBytesReached && lineCount < input.requestedLines) {
       parts.push('End of file reached.');
     }
     if (input.truncatedLineNumbers.length > 0) {
diff --git a/packages/agent-core/test/tools/read.test.ts b/packages/agent-core/test/tools/read.test.ts
index 4ab97c1bb..b81ad526a 100644
--- a/packages/agent-core/test/tools/read.test.ts
+++ b/packages/agent-core/test/tools/read.test.ts
@@ -622,6 +622,19 @@ describe('ReadTool', () => {
     expect(result.output).not.toContain(`${String(MAX_LINES + 1)}\tline ${String(MAX_LINES + 1)}`);
   });
 
+  it('reports both line and byte caps when both limits are hit', async () => {
+    const longLine = 'x'.repeat(200);
+    const content = Array.from({ length: MAX_LINES + 1 }, () => longLine).join('\n');
+    const tool = toolWithContent(content);
+
+    const result = await executeTool(tool, context({ path: '/tmp/dual-limit.txt' }));
+    const output = toolContentString(result);
+
+    expect(output).toContain(`Max ${String(MAX_LINES)} lines reached.`);
+    expect(output).toContain(`Max ${String(MAX_BYTES)} bytes reached.`);
+    expect(output).not.toContain('End of file reached.');
+  });
+
   it('tail byte truncation keeps the newest lines closest to EOF', async () => {
     const numLines = Math.floor(MAX_BYTES / 1001) + 20;
     const content = Array.from({ length: numLines }, (_, i) => {