local_ydb_apply_schema
Validate or apply YDB table DDL through the official YDB JS SDK. It accepts raw YQL DDL for PRAGMA plus CREATE TABLE, ALTER TABLE, and DROP TABLE; action=apply validates first and executes only with confirm=true.
This record as markdown: /tools/local-ydb/local-ydb-apply-schema.md
What local_ydb_apply_schema does on Local Ydb
AI agents use local_ydb_apply_schema to create or update resources in Local Ydb, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Local Ydb environment.
Why local_ydb_apply_schema is rated Medium
An AI agent can call local_ydb_apply_schema faster than any human can review: one bad instruction and it creates or modifies resources in Local Ydb by the hundred, each call as confident as the last.
Attacks that exploit this kind of access
The rule that runs local_ydb_apply_schema safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Local Ydb, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For local_ydb_apply_schema, this is the rule to start with:
local_ydb_apply_schema stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Local Ydb, apply this rule, and every local_ydb_apply_schema call is checked against it from then on.
Questions about local_ydb_apply_schema
Validate or apply YDB table DDL through the official YDB JS SDK. It accepts raw YQL DDL for PRAGMA plus CREATE TABLE, ALTER TABLE, and DROP TABLE; action=apply validates first and executes only with confirm=true. It is categorised as a Write tool in the Local Ydb MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Local Ydb MCP server in PolicyLayer and add a rule for local_ydb_apply_schema: 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 Local Ydb. Nothing to install.
local_ydb_apply_schema is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the local_ydb_apply_schema 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 local_ydb_apply_schema. 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.
local_ydb_apply_schema is provided by the Local Ydb MCP server (@astandrik/local-ydb-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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