How do I stop an LLM from generating raw SQL?

You cannot reliably stop an LLM from generating raw SQL through prompting alone — you must architecturally prevent the generated SQL from executing without validation. LLMs are stochastic text generators. Even with structured output modes, they will eventually produce unexpected, malformed, or malicious SQL in edge cases.

The risks of LLM-generated SQL:

• Prompt-to-SQL injection: Attackers craft prompts that cause the LLM to generate DROP TABLE, DELETE FROM, or GRANT ALL statements
• Hallucinated queries: LLMs invent table names, column names, and JOIN conditions that don't exist in your schema
• Privilege escalation: The LLM generates queries that access tables or schemas beyond the user's authorization
• Data exposure: SELECT * queries that return PII, credentials, or data from other tenants

Best practice from the developer community: "Use frameworks that prevent the LLM from generating raw SQL. Instead, allow it to interact only through pre-defined, safe REST API endpoints."

Exogram's Deterministic Inference layer (Layer 2) validates every database operation against your declared schema. If the LLM generates a query referencing a non-existent table, a restricted column, or a forbidden operation type, it's blocked in 0.07ms with an HTTP 400 — before it ever reaches your database. The LLM proposes queries. Exogram validates them deterministically.