alt Hacker News> # External mode — you manage llama-server, forge proxies it
> python -m forge.proxy --backend-url http://localhost:8080 --port 8081
This is a good example because I've currently stuck with llama.cpp's UI. I can read your code (or throw Gemma at it =p ) but thought I'd ask anyway.
In this example, what is it exactly that your proxy is fortifying? The HTTP SSE requests? (Those would be `/chat/completions`.)
Yes that's correct !
/v1/chat/completions is the entry point.
In proxy mode, here's what forge applies on each request (handler.py builds these):
Response validation: ResponseValidator(tool_names) checks each tool call against the declared tools array. If the model emits a call to a name not in tools[], or a malformed call shape, it's caught before the response goes back.
Rescue parsing: When the model emits tool calls in the wrong format — JSON in a code fence, [TOOL_CALLS]name{args} (Mistral), <tool_call>...</tool_call> (Qwen XML) — rescue parsers extract the structured call and re-emit it in the canonical OpenAI tool_calls schema. This is the biggest practical lift, especially on Mistral-family models that ignore native FC and emit their own bracket syntax.
Retry loop with error tracking: ErrorTracker(max_retries=N) — if validation fails, forge retries inference up to N times with a corrective tool-result message on the canonical channel, rather than returning a malformed response to your caller. From your perspective the proxy looks like a single request that just took a few extra ms.
What proxy mode does NOT do (because it's single-shot, not multi-turn): prerequisite/step enforcement (those need a workflow definition spanning turns), context compaction, session memory. For that surface you wrap the WorkflowRunner class in Python — proxy mode trades that depth for "use forge with your existing setup, no Python rewrite."
So yes — the proxy is fortifying the response shape and retry behavior of /v1/chat/completions. The full agentic guardrails are at the Python class level above it.
For greenfield projects, I've been building on forge native using WorkflowRunner so I get all guardrails. But obviously as a drop-in replacement in existing systems then proxy is the way to go.