oraios/serena · error · ValueError

Cannot extract symbols from file {relative_path}. Active lan

Error message

Cannot extract symbols from file {relative_path}. Active language servers: {[l.value for l in self.agent.get_active_language_server_ids()]}

What it means

Even for an existing file, the active language server(s) may not be able to analyze its type. When symbol_retriever.can_analyze_file returns False, the tool raises ValueError listing the currently active language servers so the caller can see the mismatch.

Source

Thrown at src/serena/tools/symbol_tools.py:109

        return self._limit_length(result_json_str, max_answer_chars, shortened_result_factories=shortened_results)

    def get_symbol_overview(self, relative_path: str, depth: int = 0) -> list[LanguageServerSymbol.OutputDict]:
        """
        :param relative_path: relative path to a source file
        :param depth: the depth up to which descendants shall be retrieved
        :return: a list of symbol dictionaries representing the symbol overview of the file
        """
        symbol_retriever = self.create_language_server_symbol_retriever()

        # The symbol overview is capable of working with both files and directories,
        # but we want to ensure that the user provides a file path.
        file_path = os.path.join(self.project.project_root, relative_path)
        if not os.path.exists(file_path):
            raise FileNotFoundError(f"File or directory {relative_path} does not exist in the project.")
        if os.path.isdir(file_path):
            raise ValueError(f"Expected a file path, but got a directory path: {relative_path}. ")
        if not symbol_retriever.can_analyze_file(relative_path):
            raise ValueError(
                f"Cannot extract symbols from file {relative_path}. Active language servers: {[l.value for l in self.agent.get_active_language_server_ids()]}"
            )

        symbols = symbol_retriever.get_symbol_overview(relative_path)[relative_path]

        def child_inclusion_predicate(s: LanguageServerSymbol) -> bool:
            return not s.is_low_level()

        symbol_dicts = []
        for symbol in symbols:
            symbol_dicts.append(
                symbol.to_dict(
                    name_path=False,
                    name=True,
                    depth=depth,
                    kind=True,
                    relative_path=False,
                    location=False,

View on GitHub (pinned to 7fcbca7e62)

Solutions

1. Point the tool at a source file of a language with an active language server
2. Configure/enable the language server for that file type in serena config
3. Check logs for language-server startup failures and fix them, then retry

Example fix

// before
get_symbol_overview.apply(relative_path='README.md')
// ValueError: Cannot extract symbols...

// after
if file.suffix in ('.py', '.ts', '.go', ...):  # LS-supported
    get_symbol_overview.apply(relative_path=str(file))

supported_exts = {e for ls in agent.get_active_language_server_ids()
                  for e in EXTENSIONS_FOR[ls]}  # e.g. py, ts, go...
if Path(relative_path).suffix not in supported_exts:
    raise SkipToolCall(f'{relative_path} not analyzable')

def analyzable(rel: str) -> bool:
    return Path(rel).suffix in SUPPORTED_SUFFIXES  # from active LS config

try:
    overview = symbol_tool.get_symbol_overview(relative_path=rel)
except ValueError as e:
    if 'Cannot extract symbols' in str(e):
        overview = text_based_fallback(rel)  # grep/AST without LS
    else:
        raise

When it happens

Trigger: Requesting symbols from a file with an extension not covered by any active language server (e.g. a .json, .txt, or a language whose LS isn't enabled); a language server failed to start so its languages are inactive.

Common situations: Pointing symbol tools at config/docs files; missing language server configuration for the project's language; LS crashed at startup so can_analyze_file fails for otherwise supported files.

Related errors

• No symbol declaration found at the location of the regex mat
• FindSymbolTool returned no results
• Invalid language server: '{orig_language_str}'.\nValid value
• The language server manager is not initialized, indicating a
• name_path_pattern must not be empty or contain only wildcard

AI-assisted analysis of oraios/serena@7fcbca7e62 (2026-08-29). Data as JSON: /api/errors/0c909213c760ec68. Report an issue: GitHub.