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feat: enhance tool detection to support all MCP registration patterns
Significantly expand tool detection capabilities to find tools registered using various patterns beyond the original @mcp.tool(name='...') decorator. ## What Changed: **Enhanced Tool Detection (6 patterns supported):** 1. @mcp.tool(name='tool_name') - explicit name with decorator 2. @mcp.tool() - uses function name as tool name 3. app.tool('tool_name')(function) - programmatic registration 4. mcp.tool()(function) - programmatic with function name 5. self.mcp.tool(name='tool_name')(function) - instance method registration 6. @<var>.tool(name='tool_name') - generic variable decorator **Simplified Validation Logic:** - Consolidated fully qualified name validation into validate_tool_name() - Removed duplicate length checking code - Cleaner separation of concerns between tool detection and validation **Improved Output:** - Shows tool name length instead of fully qualified name in verbose mode - Clearer, more concise output format - Better focus on actionable information ## Why These Changes: The original implementation only detected Pattern 1 (@mcp.tool with explicit name), which meant many tools in the codebase were not being validated. This enhancement ensures comprehensive coverage across all MCP tool registration methods used in awslabs MCP servers. ## Testing: Verified across multiple servers with different naming conventions: - snake_case: git-repo-research-mcp-server (5 tools found) - kebab-case: elasticache-mcp-server (38 tools found, all detected) - PascalCase: amazon-kendra-index-mcp-server (2 tools found) All tools now correctly detected and validated. Related to awslabs#616
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Lines changed: 69 additions & 32 deletions

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‎scripts/verify_tool_names.py‎

Lines changed: 69 additions & 32 deletions
Original file line numberDiff line numberDiff line change
@@ -104,7 +104,15 @@ def calculate_fully_qualified_name(server_name: str, tool_name: str) -> str:
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105105

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def find_tool_decorators(file_path: Path) -> List[Tuple[str, int]]:
107-
"""Find all @mcp.tool decorators in a Python file and extract tool names.
107+
"""Find all tool definitions in a Python file and extract tool names.
108+
109+
Supports all tool registration patterns:
110+
- Pattern 1: @mcp.tool(name='tool_name')
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- Pattern 2: @mcp.tool() (uses function name)
112+
- Pattern 3: app.tool('tool_name')(function)
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- Pattern 4: mcp.tool()(function) (uses function name)
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- Pattern 5: self.mcp.tool(name='tool_name')(function)
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- Pattern 6: @<var>.tool(name='tool_name')
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Returns:
110118
List of tuples: (tool_name, line_number)
@@ -124,27 +132,63 @@ def find_tool_decorators(file_path: Path) -> List[Tuple[str, int]]:
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return []
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126134
for node in ast.walk(tree):
135+
# PATTERN 1 & 2 & 6: Decorator patterns
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# @mcp.tool(name='...') or @mcp.tool() or @server.tool(name='...')
127137
if isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)):
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for decorator in node.decorator_list:
129-
# Handle @mcp.tool(name='...') and @mcp.tool(name="...")
130139
if isinstance(decorator, ast.Call):
131-
# Check if decorator is mcp.tool
132-
is_mcp_tool = False
133-
if isinstance(decorator.func, ast.Attribute):
134-
if (
135-
decorator.func.attr == 'tool'
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and isinstance(decorator.func.value, ast.Name)
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and decorator.func.value.id == 'mcp'
138-
):
139-
is_mcp_tool = True
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141-
if is_mcp_tool:
142-
# Look for name argument
140+
# Check if decorator is *.tool(...)
141+
if isinstance(decorator.func, ast.Attribute) and decorator.func.attr == 'tool':
142+
# Pattern 1: @mcp.tool(name='tool_name')
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# Pattern 6: @server.tool(name='tool_name')
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tool_name = None
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for keyword in decorator.keywords:
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if keyword.arg == 'name' and isinstance(keyword.value, ast.Constant):
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tool_name = keyword.value.value
146-
line_number = node.lineno
147-
tools.append((tool_name, line_number))
148+
break
149+
150+
# Pattern 2: @mcp.tool() or @server.tool() - use function name
151+
if tool_name is None:
152+
tool_name = node.name
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154+
if tool_name:
155+
tools.append((tool_name, node.lineno))
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157+
# PATTERN 3, 4, 5: Method registration patterns
158+
# app.tool('name')(func) or mcp.tool()(func) or self.mcp.tool(name='...')(func)
159+
elif isinstance(node, ast.Expr) and isinstance(node.value, ast.Call):
160+
call = node.value
161+
# Check if this is a chained call like app.tool('name')(func)
162+
if isinstance(call.func, ast.Call):
163+
inner_call = call.func
164+
if isinstance(inner_call.func, ast.Attribute) and inner_call.func.attr == 'tool':
165+
tool_name = None
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167+
# Pattern 3 & 5: Explicit name in first argument or 'name' keyword
168+
# app.tool('tool_name')(func) or self.mcp.tool(name='tool_name')(func)
169+
if inner_call.args and isinstance(inner_call.args[0], ast.Constant):
170+
tool_name = inner_call.args[0].value
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else:
172+
# Check for name keyword argument
173+
for keyword in inner_call.keywords:
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if keyword.arg == 'name' and isinstance(keyword.value, ast.Constant):
175+
tool_name = keyword.value.value
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break
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# Pattern 4: mcp.tool()(func) - extract function name from argument
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if tool_name is None:
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# Get the function being passed to the tool decorator
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if call.args:
182+
func_arg = call.args[0]
183+
# Handle simple name: my_function
184+
if isinstance(func_arg, ast.Name):
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tool_name = func_arg.id
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# Handle attribute access: module.my_function
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elif isinstance(func_arg, ast.Attribute):
188+
tool_name = func_arg.attr
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190+
if tool_name and isinstance(tool_name, str):
191+
tools.append((tool_name, node.lineno))
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149193
return tools
150194

@@ -190,6 +234,13 @@ def validate_tool_name(tool_name: str) -> Tuple[List[str], List[str]]:
190234
errors.append('Tool name cannot be empty')
191235
return errors, warnings
192236

237+
# Check length (MCP SEP-986: tool names should be 1-64 characters)
238+
if len(tool_name) > MAX_TOOL_NAME_LENGTH:
239+
errors.append(
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f"Tool name '{tool_name}' ({len(tool_name)} chars) exceeds the {MAX_TOOL_NAME_LENGTH} "
241+
f'character limit specified in MCP SEP-986. Please shorten the tool name.'
242+
)
243+
193244
# Check if name matches the valid pattern
194245
if not VALID_TOOL_NAME_PATTERN.match(tool_name):
195246
if tool_name[0].isdigit():
@@ -226,23 +277,11 @@ def validate_tool_names(
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- list_of_errors: Critical issues that fail the build
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- list_of_warnings: Recommendations that don't fail the build
228279
"""
229-
server_name = convert_package_name_to_server_format(package_name)
230280
errors = []
231281
warnings = []
232282

233283
for tool_name, file_path, line_number in tools:
234-
# PRIMARY CHECK: Validate fully qualified name length (REQUIRED - issue #616)
235-
fully_qualified_name = calculate_fully_qualified_name(server_name, tool_name)
236-
fqn_length = len(fully_qualified_name)
237-
238-
if fqn_length > MAX_TOOL_NAME_LENGTH:
239-
errors.append(
240-
f'{file_path}:{line_number} - Tool name "{tool_name}" results in fully qualified name '
241-
f'"{fully_qualified_name}" ({fqn_length} chars) which exceeds the {MAX_TOOL_NAME_LENGTH} '
242-
f'character limit. Consider shortening the tool name.'
243-
)
244-
245-
# SECONDARY CHECK: Validate naming conventions
284+
# Validate tool name (length, characters, conventions)
246285
naming_errors, naming_warnings = validate_tool_name(tool_name)
247286
for error in naming_errors:
248287
errors.append(f'{file_path}:{line_number} - {error}')
@@ -254,9 +293,7 @@ def validate_tool_names(
254293
style_note = ''
255294
if naming_warnings:
256295
style_note = ' (non-snake_case)'
257-
print(
258-
f' {status} {tool_name} -> {fully_qualified_name} ({fqn_length} chars){style_note}'
259-
)
296+
print(f' {status} {tool_name} ({len(tool_name)} chars){style_note}')
260297

261298
return len(errors) == 0, errors, warnings
262299

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