docs(tools): clarify coding tool guidance

nanobot/agent/tools/apply_patch.py

@@ -298,11 +298,14 @@ class ApplyPatchTool(_FsTool):
     @property
     def description(self) -> str:
         return (
-            "Apply a structured patch for code edits. The patch must include "
+            "Default tool for code edits. Apply a structured patch with "
             "*** Begin Patch and *** End Patch. Supports Add File, Update File, "
-            "Delete File, and Move to. Paths must be relative. Prefer this for "
+            "Delete File, and Move to across one or more files. Use this for "
-            "multi-file coding changes; use edit_file for small exact replacements. "
+            "multi-file changes, structural edits, generated code, or any edit "
-            "Set dry_run=true to validate and preview the change without writing files."
+            "where a reviewable patch is clearer than an exact replacement. "
+            "Paths must be relative. Set dry_run=true to validate and preview "
+            "the change summary without writing files. Use edit_file only for "
+            "small exact replacements copied from read_file."
         )
 
     async def execute(self, patch: str, dry_run: bool = False, **kwargs: Any) -> str:

nanobot/agent/tools/exec_session.py

@@ -424,11 +424,12 @@ class WriteStdinTool(Tool):
     @property
     def description(self) -> str:
         return (
-            "Write text to a running exec session and return recent output. "
+            "Interact with a running exec session created by exec with "
-            "Use chars='' to poll without writing. Set close_stdin=true to send EOF, "
+            "yield_time_ms. Use chars='' to poll without writing, chars to send "
-            "or terminate=true to stop the session. Use wait_for to keep polling "
+            "stdin, close_stdin=true to send EOF, or terminate=true to stop the "
-            "until expected output appears. Sessions finish automatically when "
+            "process. Use wait_for with wait_timeout_ms for dev servers, test "
-            "their process exits."
+            "watchers, and prompts where you need to wait for expected output. "
+            "Do not use this to start new commands; start them with exec."
         )
 
     async def execute(
@@ -561,7 +562,8 @@ class ListExecSessionsTool(Tool):
         return (
             "List active long-running exec sessions, including session_id, cwd, "
             "elapsed time, idle time, remaining timeout, and command preview. "
-            "Use this to recover a session_id before polling with write_stdin."
+            "Use this to recover a session_id after context shifts before "
+            "polling, writing stdin, or terminating with write_stdin."
         )
 
     @property

nanobot/agent/tools/filesystem.py

@@ -158,6 +158,9 @@ class ReadFileTool(_FsTool):
             "Text output format: LINE_NUM|CONTENT. "
             "Images return visual content for analysis. "
             "Supports PDF, DOCX, XLSX, PPTX documents. "
+            "Use find_files/list_dir first when the path is uncertain. "
+            "Read the relevant range before editing so replacements or patches "
+            "are based on current content. "
             "Use offset and limit for large text files. "
             "Use force=true to re-read content even if unchanged. "
             "Reads exceeding ~128K chars are truncated."
@@ -384,9 +387,10 @@ class WriteFileTool(_FsTool):
     @property
     def description(self) -> str:
         return (
-            "Write content to a file. Overwrites if the file already exists; "
+            "Create a new file or intentionally replace an entire file with "
-            "creates parent directories as needed. "
+            "the provided content. Overwrites existing files and creates parent "
-            "For partial edits, prefer edit_file instead."
+            "directories as needed. For code changes or partial edits, prefer "
+            "apply_patch; use edit_file only for small exact replacements."
         )
 
     async def execute(self, path: str | None = None, content: str | None = None, **kwargs: Any) -> str:
@@ -711,10 +715,13 @@ class EditFileTool(_FsTool):
     @property
     def description(self) -> str:
         return (
-            "Edit a file by replacing old_text with new_text. "
+            "Perform a small, exact replacement in one file by replacing "
-            "Tolerates minor whitespace/indentation differences and curly/straight quote mismatches. "
+            "old_text with new_text. Use this for narrow text substitutions "
-            "If old_text matches multiple times, you must provide more context "
+            "with old_text copied from read_file. For multi-file, structural, "
-            "or set occurrence/line_hint/replace_all. Shows a diff of the closest match on failure."
+            "or generated code edits, prefer apply_patch. If old_text matches "
+            "multiple times, provide more context or set occurrence, line_hint, "
+            "replace_all, and expected_replacements. Shows closest-match "
+            "diagnostics on failure."
         )
 
     @staticmethod

nanobot/agent/tools/search.py

@@ -130,8 +130,10 @@ class FindFilesTool(_SearchTool):
     def description(self) -> str:
         return (
             "Find files by path fragment, glob, or file type. "
-            "Use this before read_file when you need to locate files. "
+            "Use this before read_file when you need to locate files, and "
-            "Returns workspace-relative paths and skips common dependency/build directories."
+            "prefer it over shell find/ls for ordinary workspace discovery. "
+            "Returns workspace-relative paths and skips common dependency/build "
+            "directories."
         )
 
     @property
@@ -289,7 +291,8 @@ class GrepTool(_SearchTool):
         return (
             "Search file contents with a regex pattern. "
             "Default output_mode is files_with_matches (file paths only); "
-            "use content mode for matching lines with context. "
+            "use content mode for matching lines with context. Prefer this "
+            "over shell grep for ordinary workspace searches. "
             "Skips binary and files >2 MB. Supports glob/type filtering."
         )
 

nanobot/agent/tools/shell.py

@@ -211,8 +211,10 @@ class ExecTool(Tool):
     def description(self) -> str:
         return (
             "Execute a shell command and return its output. "
-            "Prefer read_file/write_file/edit_file over cat/echo/sed, "
+            "Use this for tests, builds, package commands, git commands, and "
-            "and grep/glob over shell find/grep. "
+            "other process execution. Prefer read_file/find_files/grep for "
+            "inspection and apply_patch/write_file/edit_file for file changes "
+            "instead of cat, shell find/grep, echo, or sed. "
             "Use -y or --yes flags to avoid interactive prompts. "
             "For long-running or interactive commands, pass yield_time_ms; "
             "if the command keeps running, exec returns a session_id that can "

tests/tools/test_tool_descriptions.py

@@ -0,0 +1,46 @@
+from nanobot.agent.tools.apply_patch import ApplyPatchTool
+from nanobot.agent.tools.exec_session import ListExecSessionsTool, WriteStdinTool
+from nanobot.agent.tools.filesystem import EditFileTool, ReadFileTool, WriteFileTool
+from nanobot.agent.tools.search import FindFilesTool, GrepTool
+from nanobot.agent.tools.shell import ExecTool
+
+
+def test_coding_tool_descriptions_steer_editing_priority() -> None:
+    apply_patch = ApplyPatchTool().description.lower()
+    edit_file = EditFileTool().description.lower()
+    write_file = WriteFileTool().description.lower()
+
+    assert "default tool for code edits" in apply_patch
+    assert "multi-file" in apply_patch
+    assert "dry_run=true" in apply_patch
+    assert "edit_file only for small exact replacements" in apply_patch
+
+    assert "small, exact replacement" in edit_file
+    assert "copied from read_file" in edit_file
+    assert "prefer apply_patch" in edit_file
+
+    assert "replace an entire file" in write_file
+    assert "prefer apply_patch" in write_file
+
+
+def test_coding_tool_descriptions_steer_discovery_and_shell_usage() -> None:
+    read_file = ReadFileTool().description.lower()
+    find_files = FindFilesTool().description.lower()
+    grep = GrepTool().description.lower()
+    exec_tool = ExecTool().description.lower()
+    write_stdin = WriteStdinTool().description.lower()
+    list_sessions = ListExecSessionsTool().description.lower()
+
+    assert "find_files/list_dir first" in read_file
+    assert "before editing" in read_file
+    assert "prefer it over shell find/ls" in find_files
+    assert "prefer this over shell grep" in grep
+
+    assert "tests, builds" in exec_tool
+    assert "prefer read_file/find_files/grep" in exec_tool
+    assert "apply_patch/write_file/edit_file" in exec_tool
+    assert "yield_time_ms" in exec_tool
+
+    assert "do not use this to start new commands" in write_stdin
+    assert "wait_for" in write_stdin
+    assert "recover a session_id" in list_sessions