diff --git a/backend/open_webui/env.py b/backend/open_webui/env.py
index ea19b426ed..694b92ec76 100644
--- a/backend/open_webui/env.py
+++ b/backend/open_webui/env.py
@@ -1078,6 +1078,28 @@ SENTENCE_TRANSFORMERS_CROSS_ENCODER_SIGMOID_ACTIVATION_FUNCTION = (
     os.getenv('SENTENCE_TRANSFORMERS_CROSS_ENCODER_SIGMOID_ACTIVATION_FUNCTION', 'True').lower() == 'true'
 )
 
+####################################
+# KNOWLEDGE TOOLS
+####################################
+
+
+def _int_env(name: str, default: int) -> int:
+    try:
+        return max(int(os.getenv(name) or default), 1)
+    except (ValueError, TypeError):
+        return default
+
+
+# Total output of a single kb_exec call, whatever the command.
+KB_EXEC_MAX_OUTPUT_CHARS = _int_env('KB_EXEC_MAX_OUTPUT_CHARS', 30_000)
+# Files a single kb_exec grep may scan before it asks for a narrower scope.
+KB_EXEC_MAX_GREP_FILES = _int_env('KB_EXEC_MAX_GREP_FILES', 200)
+# Matching lines returned by kb_exec grep and grep_knowledge_files.
+KNOWLEDGE_GREP_MAX_MATCHES = _int_env('KNOWLEDGE_GREP_MAX_MATCHES', 50)
+# Characters returned by view_file / view_knowledge_file.
+VIEW_FILE_MAX_CHARS = _int_env('VIEW_FILE_MAX_CHARS', 100_000)
+VIEW_FILE_DEFAULT_MAX_CHARS = _int_env('VIEW_FILE_DEFAULT_MAX_CHARS', 10_000)
+
 ####################################
 # TOOLS/FUNCTIONS PIP OPTIONS
 ####################################
diff --git a/backend/open_webui/tools/builtin.py b/backend/open_webui/tools/builtin.py
index ebbc9148cc..03b18ca655 100644
--- a/backend/open_webui/tools/builtin.py
+++ b/backend/open_webui/tools/builtin.py
@@ -17,6 +17,11 @@ from typing import Literal, Optional
 from fastapi import HTTPException, Request
 
 from open_webui.config import RAG_EMBEDDING_QUERY_PREFIX
+from open_webui.env import (
+    KNOWLEDGE_GREP_MAX_MATCHES,
+    VIEW_FILE_DEFAULT_MAX_CHARS,
+    VIEW_FILE_MAX_CHARS,
+)
 from open_webui.models.channels import Channel, ChannelMember, Channels
 from open_webui.models.chats import Chats
 from open_webui.models.config import Config
@@ -2157,12 +2162,6 @@ async def search_knowledge_files(
         return json.dumps({'error': str(e)})
 
 
-# Hard cap for view_file / view_knowledge_file output
-MAX_VIEW_FILE_CHARS = 100_000
-DEFAULT_VIEW_FILE_MAX_CHARS = 10_000
-MAX_GREP_RESULTS = 50
-
-
 async def _get_accessible_chat_files(
     files: Optional[list[dict]],
     user: dict,
@@ -2229,7 +2228,7 @@ def _grep_file_models(
             if matches(line):
                 file_matches += 1
                 total_matches += 1
-                if not count_only and len(results) < MAX_GREP_RESULTS:
+                if not count_only and len(results) < KNOWLEDGE_GREP_MAX_MATCHES:
                     results.append(f'{file.id}  {file.filename}:{i}: {line}')
 
         if file_matches > 0 and count_only:
@@ -2244,8 +2243,8 @@ def _grep_file_models(
         return f'No matches for "{pattern}"'
 
     output = '\n'.join(results)
-    if total_matches > MAX_GREP_RESULTS:
-        output += f'\n[{MAX_GREP_RESULTS} of {total_matches} matches shown — use file_id to narrow]'
+    if total_matches > KNOWLEDGE_GREP_MAX_MATCHES:
+        output += f'\n[{KNOWLEDGE_GREP_MAX_MATCHES} of {total_matches} matches shown — use file_id to narrow]'
     return output
 
 
@@ -2589,7 +2588,7 @@ async def grep_knowledge_files(
 async def view_file(
     file_id: str,
     offset: int = 0,
-    max_chars: int = DEFAULT_VIEW_FILE_MAX_CHARS,
+    max_chars: int = VIEW_FILE_DEFAULT_MAX_CHARS,
     line_numbers: bool = False,
     start_line: Optional[int] = None,
     end_line: Optional[int] = None,
@@ -2602,7 +2601,7 @@ async def view_file(
 
     :param file_id: The ID of the file to retrieve
     :param offset: Character offset to start reading from (default: 0)
-    :param max_chars: Maximum characters to return (default: 10000, hard cap: 100000)
+    :param max_chars: Maximum characters to return (a server-side hard cap applies)
     :param line_numbers: If true, prefix each line with its 1-indexed line number
     :param start_line: Optional 1-indexed start line (overrides offset/max_chars when set)
     :param end_line: Optional 1-indexed end line (inclusive)
@@ -2624,10 +2623,10 @@ async def view_file(
         try:
             max_chars = int(max_chars)
         except ValueError:
-            max_chars = DEFAULT_VIEW_FILE_MAX_CHARS
+            max_chars = VIEW_FILE_DEFAULT_MAX_CHARS
 
     # Enforce hard cap
-    max_chars = min(max(max_chars, 1), MAX_VIEW_FILE_CHARS)
+    max_chars = min(max(max_chars, 1), VIEW_FILE_MAX_CHARS)
     offset = max(offset, 0)
 
     try:
@@ -2705,7 +2704,7 @@ async def view_file(
 async def view_knowledge_file(
     file_id: str,
     offset: int = 0,
-    max_chars: int = DEFAULT_VIEW_FILE_MAX_CHARS,
+    max_chars: int = VIEW_FILE_DEFAULT_MAX_CHARS,
     line_numbers: bool = False,
     start_line: Optional[int] = None,
     end_line: Optional[int] = None,
@@ -2717,7 +2716,7 @@ async def view_knowledge_file(
 
     :param file_id: The ID of the file to retrieve
     :param offset: Character offset to start reading from (default: 0)
-    :param max_chars: Maximum characters to return (default: 10000, hard cap: 100000)
+    :param max_chars: Maximum characters to return (a server-side hard cap applies)
     :param line_numbers: If true, prefix each line with its 1-indexed line number
     :param start_line: Optional 1-indexed start line (overrides offset/max_chars when set)
     :param end_line: Optional 1-indexed end line (inclusive)
@@ -2739,10 +2738,10 @@ async def view_knowledge_file(
         try:
             max_chars = int(max_chars)
         except ValueError:
-            max_chars = DEFAULT_VIEW_FILE_MAX_CHARS
+            max_chars = VIEW_FILE_DEFAULT_MAX_CHARS
 
     # Enforce hard cap
-    max_chars = min(max(max_chars, 1), MAX_VIEW_FILE_CHARS)
+    max_chars = min(max(max_chars, 1), VIEW_FILE_MAX_CHARS)
     offset = max(offset, 0)
 
     try:
diff --git a/backend/open_webui/tools/knowledge_fs.py b/backend/open_webui/tools/knowledge_fs.py
index 419614c18e..eed252ff2b 100644
--- a/backend/open_webui/tools/knowledge_fs.py
+++ b/backend/open_webui/tools/knowledge_fs.py
@@ -19,15 +19,16 @@ from typing import Optional
 import regex
 from fastapi import Request
 
+from open_webui.env import (
+    KB_EXEC_MAX_GREP_FILES,
+    KB_EXEC_MAX_OUTPUT_CHARS,
+    KNOWLEDGE_GREP_MAX_MATCHES,
+)
+
 log = logging.getLogger(__name__)
 
-# Limits
-MAX_CAT_CHARS = 100_000
-DEFAULT_CAT_CHARS = 10_000
-MAX_GREP_FILES = 200
 DEFAULT_HEAD_LINES = 10
 DEFAULT_TAIL_LINES = 10
-MAX_GREP_MATCHES = 50
 
 # Matching time allowed per tool call. Backtracking cost is exponential in the length of the
 # matched text, so capping the pattern or the line does not bound it.
@@ -627,21 +628,10 @@ async def _kb_cat(args: list[str], flags: set[str], user: dict, model_knowledge:
         return resolved['error']
 
     content = resolved['content']
-    show_numbers = 'n' in flags
-
-    if len(content) > MAX_CAT_CHARS:
-        content = content[:MAX_CAT_CHARS]
-        truncated = True
-    else:
-        truncated = False
-
-    if show_numbers:
+    if 'n' in flags:
         lines = content.split('\n')
         content = '\n'.join(f'{i}: {line}' for i, line in enumerate(lines, 1))
 
-    if truncated:
-        content += f'\n[truncated at {MAX_CAT_CHARS:,} chars — use head/tail/sed/grep to navigate]'
-
     return content
 
 
@@ -790,7 +780,7 @@ async def _kb_grep(
     if ext_filter:
         accessible = [f for f in accessible if f['filename'].endswith(f'.{ext_filter}')]
 
-    if len(accessible) > MAX_GREP_FILES:
+    if len(accessible) > KB_EXEC_MAX_GREP_FILES:
         return f'Too many files ({len(accessible)}). Scope your search: grep "{pattern}" docs/ or grep "{pattern}" *.py'
 
     from open_webui.models.files import Files
@@ -822,7 +812,7 @@ async def _kb_grep(
 
             if not count_only and not filenames_only:
                 for line_num, line_text in file_matches:
-                    if len(results) < MAX_GREP_MATCHES:
+                    if len(results) < KNOWLEDGE_GREP_MAX_MATCHES:
                         results.append(f'{file_info["id"]}  {file_info["filename"]}:{line_num}: {line_text.rstrip()}')
 
     if count_only:
@@ -841,8 +831,8 @@ async def _kb_grep(
         return f'No matches for "{pattern}" across {len(accessible)} files'
 
     output = '\n'.join(results)
-    if total_matches > MAX_GREP_MATCHES:
-        output += f'\n[showing {MAX_GREP_MATCHES} of {total_matches} matches]'
+    if total_matches > KNOWLEDGE_GREP_MAX_MATCHES:
+        output += f'\n[showing {KNOWLEDGE_GREP_MAX_MATCHES} of {total_matches} matches]'
     return output
 
 
@@ -1181,7 +1171,13 @@ async def kb_exec(
 
         # One budget for the whole command: a per-search budget would multiply by segment count.
         with match_budget():
-            return await _execute_pipeline(segments, __user__, __model_knowledge__)
+            output = await _execute_pipeline(segments, __user__, __model_knowledge__)
+        if len(output) > KB_EXEC_MAX_OUTPUT_CHARS:
+            output = output[:KB_EXEC_MAX_OUTPUT_CHARS] + (
+                f'\n[output truncated at {KB_EXEC_MAX_OUTPUT_CHARS:,} chars'
+                ' — narrow the command with a path, glob, head/tail/sed or grep]'
+            )
+        return output
     except Exception as e:
         log.exception(f'kb_exec error: {e}')
         return f'Error: {e}'