db_query
Execute a database query via CLI (sqlite3, psql, mysql, redis-cli). For adapter-routed queries use data_query.
This record as markdown: /tools/io-github-kivanccakmak-yaver/db-query.md
What db_query does on Yaver
AI agents invoke db_query to trigger actions in Yaver. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
| Parameter | Type | Required | Description |
|---|---|---|---|
dsn | string | — | Connection string (or path for SQLite). Uses DATABASE_URL env if empty for postgres. |
query | string | Yes | SQL query or Redis command |
driver | string | Yes | Database: sqlite, postgres, mysql, redis |
Parameters from the server's own tool schema.
Why db_query is rated High
This tool runs arbitrary database queries through CLI tools. Depending on the query, it can read, write, or destructively delete data. Since the tool executes arbitrary SQL/commands via CLI and could include DROP, DELETE, or other destructive operations, Execute is the most appropriate category (with Destructive being a close consideration).
From the tool's definition Execute a database query via CLI (sqlite3, psql, mysql, redis-cli)
Attacks that exploit this kind of access
The rule that runs db_query safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Yaver, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For db_query, this is the rule to start with:
db_query stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Yaver, apply this rule, and every db_query call is checked against it from then on.
Questions about db_query
Execute a database query via CLI (sqlite3, psql, mysql, redis-cli). For adapter-routed queries use data_query. It is categorised as a Execute tool in the Yaver MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
db_query accepts 3 parameters: dsn, query, driver. Required: query, driver. The full parameter table on this page comes from the server's own tool schema.
Register the Yaver MCP server in PolicyLayer and add a rule for db_query: 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 Yaver. Nothing to install.
db_query is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the db_query 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 db_query. 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.
db_query is provided by the Yaver MCP server (yaver-cli). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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