From 8cf770613a4731c26419a70699bb4504df422637 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89mile=20R=C3=A9?= <emile@probo.com>
Date: Mon, 1 Jun 2026 13:39:42 +0200
Subject: [PATCH] Drop request sanitization from LLM client
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Remove sanitizeRequest and its call sites so the client no longer
strips sampling parameters based on the model registry. Unsupported
knobs are now avoided by setting the config carefully per model
rather than silently mutating outgoing requests.

Signed-off-by: Émile Ré <emile@probo.com>
---
 pkg/llm/llm.go | 77 --------------------------------------------------
 1 file changed, 77 deletions(-)

diff --git a/pkg/llm/llm.go b/pkg/llm/llm.go
index 6afedc2e0..f53c99d93 100644
--- a/pkg/llm/llm.go
+++ b/pkg/llm/llm.go
@@ -17,7 +17,6 @@ package llm
 import (
 	"context"
 	"io"
-	"strings"
 	"time"
 
 	"go.gearno.de/kit/log"
@@ -73,8 +72,6 @@ func NewClient(provider Provider, system string, opts ...Option) *Client {
 }
 
 func (c *Client) ChatCompletion(ctx context.Context, req *ChatCompletionRequest) (*ChatCompletionResponse, error) {
-	req = sanitizeRequest(ctx, c.logger, req)
-
 	ctx, span := startChatSpan(ctx, c.tracer, c.system, req)
 
 	c.logger.InfoCtx(
@@ -118,8 +115,6 @@ func (c *Client) ChatCompletion(ctx context.Context, req *ChatCompletionRequest)
 }
 
 func (c *Client) ChatCompletionStream(ctx context.Context, req *ChatCompletionRequest) (ChatCompletionStream, error) {
-	req = sanitizeRequest(ctx, c.logger, req)
-
 	ctx, span := startChatSpan(ctx, c.tracer, c.system, req)
 
 	c.logger.InfoCtx(
@@ -145,75 +140,3 @@ func (c *Client) ChatCompletionStream(ctx context.Context, req *ChatCompletionRe
 
 	return newTracedStream(stream, span), nil
 }
-
-// sanitizeRequest drops sampling parameters the target model does not
-// accept, using the default model registry. Reasoning models (e.g. the
-// GPT-5 family) reject an explicit temperature, top_p, or penalties and
-// fail the whole request with a 400, so the safest behavior is to omit
-// the unsupported knobs rather than propagate a hard error. When the
-// model is unknown to the registry the request is left untouched.
-func sanitizeRequest(ctx context.Context, logger *log.Logger, req *ChatCompletionRequest) *ChatCompletionRequest {
-	if req == nil {
-		return req
-	}
-
-	model, ok := DefaultRegistry().Lookup(req.Model)
-	if !ok {
-		return req
-	}
-
-	supports := model.Supports
-
-	dropTemperature := req.Temperature != nil && !supports.Temperature
-	dropTopP := req.TopP != nil && !supports.TopP
-	dropFrequencyPenalty := req.FrequencyPenalty != nil && !supports.FrequencyPenalty
-	dropPresencePenalty := req.PresencePenalty != nil && !supports.PresencePenalty
-	dropStop := len(req.StopSequences) > 0 && !supports.Stop
-
-	if !dropTemperature && !dropTopP && !dropFrequencyPenalty && !dropPresencePenalty && !dropStop {
-		return req
-	}
-
-	sanitized := *req
-
-	dropped := make([]string, 0, 5)
-
-	if dropTemperature {
-		sanitized.Temperature = nil
-
-		dropped = append(dropped, "temperature")
-	}
-
-	if dropTopP {
-		sanitized.TopP = nil
-
-		dropped = append(dropped, "top_p")
-	}
-
-	if dropFrequencyPenalty {
-		sanitized.FrequencyPenalty = nil
-
-		dropped = append(dropped, "frequency_penalty")
-	}
-
-	if dropPresencePenalty {
-		sanitized.PresencePenalty = nil
-
-		dropped = append(dropped, "presence_penalty")
-	}
-
-	if dropStop {
-		sanitized.StopSequences = nil
-
-		dropped = append(dropped, "stop")
-	}
-
-	logger.WarnCtx(
-		ctx,
-		"dropping unsupported sampling parameters for model",
-		log.String("model", req.Model),
-		log.String("dropped", strings.Join(dropped, ",")),
-	)
-
-	return &sanitized
-}