From 3bc1a0f6dede5494b4afe0ea2ca5f258527cf509 Mon Sep 17 00:00:00 2001
From: Diego Rodrigues de Sa e Souza
 <8016841+diegosouzapw@users.noreply.github.com>
Date: Fri, 19 Jun 2026 02:21:36 -0300
Subject: [PATCH] refactor(compression): remove vestigial SLM seam + dead
 deprecated alias (#4253)
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Integrated into release/v3.8.29 — remove vestigial SLM seam (createSLMStub/SLMInterface) + dead estimateTokensForStats alias. Validated: ultra.test.ts 39/39 green, zero code callers of the removed symbols.
---
 open-sse/services/compression/index.ts |  4 +--
 open-sse/services/compression/stats.ts |  3 --
 open-sse/services/compression/ultra.ts | 12 --------
 tests/unit/compression/ultra.test.ts   | 38 +-------------------------
 4 files changed, 3 insertions(+), 54 deletions(-)

diff --git a/open-sse/services/compression/index.ts b/open-sse/services/compression/index.ts
index 1e14216dac..062a1c8d57 100644
--- a/open-sse/services/compression/index.ts
+++ b/open-sse/services/compression/index.ts
@@ -151,8 +151,8 @@ export { compressAggressive } from "./aggressive.ts";
 
 export { STOPWORDS, FORCE_PRESERVE_RE, scoreToken, pruneByScore } from "./ultraHeuristic.ts";
 
-export type { SLMInterface, UltraCompressResult } from "./ultra.ts";
-export { createSLMStub, ultraCompress } from "./ultra.ts";
+export type { UltraCompressResult } from "./ultra.ts";
+export { ultraCompress } from "./ultra.ts";
 
 export type { UltraConfig } from "./types.ts";
 export { DEFAULT_ULTRA_CONFIG } from "./types.ts";
diff --git a/open-sse/services/compression/stats.ts b/open-sse/services/compression/stats.ts
index 9e2845cfcd..8d86f982c7 100644
--- a/open-sse/services/compression/stats.ts
+++ b/open-sse/services/compression/stats.ts
@@ -16,9 +16,6 @@ export function estimateCompressionTokens(text: string | object | null | undefin
   return Math.ceil(str.length / CHARS_PER_TOKEN);
 }
 
-/** @deprecated Use estimateCompressionTokens instead. */
-export const estimateTokensForStats = estimateCompressionTokens;
-
 export function createCompressionStats(
   originalBody: Record<string, unknown>,
   compressedBody: Record<string, unknown>,
diff --git a/open-sse/services/compression/ultra.ts b/open-sse/services/compression/ultra.ts
index 1fc3cc0fc2..f53b722213 100644
--- a/open-sse/services/compression/ultra.ts
+++ b/open-sse/services/compression/ultra.ts
@@ -5,18 +5,6 @@ import { extractTextContent, mapTextContent, type ChatMessageLike } from "./mess
 
 const COMPRESSED_PREFIX = "[COMPRESSED:";
 
-export interface SLMInterface {
-  compress(text: string, rate: number): Promise<string>;
-}
-
-export function createSLMStub(): SLMInterface {
-  return {
-    async compress(text: string, rate: number): Promise<string> {
-      return pruneByScore(text, rate);
-    },
-  };
-}
-
 export interface UltraCompressResult {
   messages: Array<{ role: string; content?: string | unknown[]; [key: string]: unknown }>;
   stats: CompressionStats;
diff --git a/tests/unit/compression/ultra.test.ts b/tests/unit/compression/ultra.test.ts
index 5788d966fe..6e05470276 100644
--- a/tests/unit/compression/ultra.test.ts
+++ b/tests/unit/compression/ultra.test.ts
@@ -6,11 +6,7 @@ import {
   STOPWORDS,
   FORCE_PRESERVE_RE,
 } from "../../../open-sse/services/compression/ultraHeuristic.ts";
-import {
-  ultraCompress,
-  createSLMStub,
-  type SLMInterface,
-} from "../../../open-sse/services/compression/ultra.ts";
+import { ultraCompress } from "../../../open-sse/services/compression/ultra.ts";
 import type { UltraConfig } from "../../../open-sse/services/compression/types.ts";
 
 describe("scoreToken", () => {
@@ -255,35 +251,3 @@ describe("ultraCompress", () => {
     assert.strictEqual(result.stats.savingsPercent, 0);
   });
 });
-
-describe("createSLMStub", () => {
-  it("should return object with compress function", () => {
-    const stub = createSLMStub();
-    assert(stub);
-    assert(typeof stub.compress === "function");
-  });
-
-  it("stub.compress should return a string", async () => {
-    const stub = createSLMStub();
-    const result = await stub.compress("hello world", 0.5);
-    assert(typeof result === "string");
-  });
-
-  it("stub.compress result should be <= input length", async () => {
-    const stub = createSLMStub();
-    const input = "the quick brown fox jumps over the lazy dog";
-    const result = await stub.compress(input, 0.5);
-    assert(result.length <= input.length);
-  });
-
-  it("stub.compress on empty string should return empty", async () => {
-    const stub = createSLMStub();
-    const result = await stub.compress("", 0.5);
-    assert.strictEqual(result, "");
-  });
-
-  it("stub should have a name or identifier", () => {
-    const stub = createSLMStub();
-    assert(stub !== null && typeof stub === "object");
-  });
-});