It's the Harness, Not the Model: David Cramer, CPO of Sentry, on Agents, Expectations vs Reality

David Cramer, CPO and co-founder of Sentry, joins us to cut through the agent hype with a working engineer's skepticism: the model is rarely what holds agents back. The harness you build around it is. We get into the Railway incident, where a coding agent found a stray CLI token and deleted a production database (and every backup) in nine seconds, and why the enforcement layer has to live below the agent, not in an advisory system prompt.

David explains Seer, Sentry's AI debugger, as the counter-example: an agent doing real work because it was given the right context, not more autonomy. He also walks through Warden, the code-review harness he built that found 100+ previously unknown vulnerabilities across Sentry and open-source projects, including full auth bypasses, for roughly $1K of compute.

We also get his contrarian-but-consistent take on why MCP is not just a shim on your API, why CLIs are harder to secure than people think, and why verification, not code generation, is still the unsolved problem.