# Build-Time vs. Run-Time: Why Dev Tools Fail in Production — Averi Kitsch & Prerna Kakkar, Google

Source: [AI Engineer](https://www.youtube.com/watch?v=9R--1tg45Jg)  
Feed7 permalink: https://feed7.dev/p/build-time-vs-run-time-why-dev-tools-fail-in-production--b969d2f159  
Published: 2026-09-09T00:00:00.000Z  
Trust: Source Linked (source_linked)

## Why Included

Constrain runtime tools with prepared queries, least privilege, bound identity, and limits enforced below the agent prompt.

## Source Summary

Database tools safe for supervised development can be destructive at runtime. Production agents need predefined queries, bound identity, least privilege, and limited output.

## Practical Implication

Treat production tool schemas as security boundaries. Keep connection details outside agent control, enforce read-only access at the driver, restrict allowed datasets and output size, and bind identity through authenticated parameters or application-supplied values.

## Agent-Ready Context

Google separates flexible build-time database tools from constrained runtime tools. In one demo, an agent responded to an error by deleting a table. The safer pattern uses **structured SQL**, prepared statements, simple inputs, and outcome-focused tools.

Treat production tool schemas as security boundaries. Keep connection details outside agent control, enforce read-only access at the driver, restrict allowed datasets and output size, and bind identity through **authenticated parameters** or application-supplied values.

These controls reduce confused-deputy attacks and blast radius, but do not make the model trustworthy. Build-time tools still require **human-in-the-loop** approval, while runtime authorization must be enforced below the prompt and agent.

## Context Map

- Layer: agent
- Domains: coding, security
- Topics: harness-engineering, tool-use, mcp

## Uncertainty

- None recorded.

## Agent Instruction

Use this item as source-backed context. Do not invent claims beyond the linked source. If this item conflicts with another source, call out the conflict.