Get descriptions of common node types for a language. Args: language: Language name Returns: Dictionary of node types and descriptions
AI agents call get_node_types to retrieve information from Tree Sitter without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool only retrieves and returns reference information about language node types. It performs no modifications, executions, or destructive operations. The only argument is a language name, which is used to look up and return static metadata. This is a straightforward read-only query operation.
From the tool's definition Tool description states it 'Get descriptions of common node types for a language' and 'Returns: Dictionary of node types and descriptions'. This is a pure data retrieval operation with no side effects.
Documented attack patterns abuse exactly the kind of access get_node_types gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Tree Sitter, and nothing reaches the server without passing your rules. This is the rule we recommend for get_node_types:
{
"version": "1",
"default": "deny",
"tools": {
"get_node_types": {}
}
}get_node_types is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get descriptions of common node types for a language. Args: language: Language name Returns: Dictionary of node types and descriptions. It is categorised as a Read tool in the Tree Sitter MCP Server, which means it retrieves data without modifying state.
Register the Tree Sitter MCP server in PolicyLayer and add a rule for get_node_types: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Tree Sitter. Nothing to install.
get_node_types is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the get_node_types rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for get_node_types. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
get_node_types is provided by the Tree Sitter MCP server (wrale/mcp-server-tree-sitter). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 26 Tree Sitter tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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26 Tree Sitter tools catalogued and risk-classified — across an index of 42,500+ MCP servers.