refactor: delegate historical-image strip to acp-kernel wire primitive (#617)

CHANGELOG.md

@@ -5,6 +5,10 @@ Versions follow the merge of a `*_release-v*` branch; CI publishes to npm on tag
 
 ## [Unreleased]
 
+### Changes
+
+- **Historical-image strip now uses the acp-kernel wire primitive (#617)**: the #618 opt-in strip (`compress.stripImages` / `compress.stripImagesKeepRecent`) was implemented locally (`src/strip-images.ts`, a per-protocol traversal mirroring `src/image-tokens.ts`). With the mechanism now sunk into acp-kernel's wire layer (kernel #215, shipped 0.0.58; this repo pins 0.0.59), the proxy calls `stripHistoricalImages` straight from `acp-kernel/wire` — identical semantics (recent-N kept, image-only messages collapse to a `[image]` placeholder, identity no-op) and a single source of truth shared with the pi/omp adapters (billion-context-pi#321). Local module deleted; only the host-side policy (config keys + default-5 constant) remains, moved to `src/compress-settings.ts`. No behavior change.
+
 ### Fixes
 
 - **Lenient compress-arg parsing: salvage single-quoted JSON before hard rejection (#603)**: weak local models (reported via omp#121) emit `compress` args with single quotes (`{'content':[{'startId':...}]}`) — a malformation class the kernel's salvage ladder (fences, trailing commas, raw newlines, double-stringification, truncated/prose-wrapped arrays) does not cover, so the whole call was rejected `kind=malformed-json`, the round was wasted, and the model saw a FAILED result that can trigger tag-echoing. `parseCompressInput` now retries once through a quote-normalization pass when the kernel recovers zero ranges or reports invalid items: a state machine converts single-quoted strings to double-quoted ones (apostrophes inside double-quoted values are data and are copied verbatim; control characters inside single-quoted regions become JSON escapes), applied to raw-string args and to object inputs whose `content` value is a stringified array. The retry wins only when it recovers strictly more ranges — valid input is never rewritten — and salvaged ranges pass the same ref-validation gate as any other range, so the worst case is a wasted round, never a wrong compression. A `[acp-compress-input] quote-salvage: recovered N range(s)` warn logs each recovery for attribution.

src/compress-settings.ts

@@ -2,6 +2,12 @@ import { DEFAULT_ABSORB_CONFIG, defaultPrompts, resolvePrompts, type AbsorbConfi
 import { findRoute, type CompressSettings, type ProviderRoutes } from "./config.js";
 import { log as loggerLog } from "./logger.js";
 
+/** Host-side policy default for `compress.stripImagesKeepRecent` (#617): how
+ *  many of the most recent messages keep their image payloads when stripping
+ *  is enabled. The strip mechanism itself lives in acp-kernel's wire layer
+ *  (kernel #215) — only the opt-in policy stays host-side. */
+export const DEFAULT_STRIP_IMAGES_KEEP_RECENT = 5;
+
 /** Resolve a raw `contextLimit` value to an absolute token count.
  *  - `number` → used as-is (absolute window).
  *  - `string` ending in `%` (e.g. `"70%"`) → that fraction of `nativeLimit`.

src/config.ts

@@ -151,11 +151,13 @@ export type CompressSettings = {
         toolName?: string;
     };
 
-/** Opt-in removal of historical image payloads (src/strip-images.ts). When
-     *  true, every message except the most recent {@link stripImagesKeepRecent}
-     *  has its image parts dropped before the wire rebuild (image-only content
-     *  collapses to an "[image]" placeholder). Off by default — the #488 image
-     *  floor / overflow 502 stays the opt-in signal until this is enabled. */
+    /** Opt-in removal of historical image payloads, executed by the kernel's
+     *  wire-layer primitive `stripHistoricalImages` from "acp-kernel/wire"
+     *  (kernel #215; host-side policy only). When true, every message except
+     *  the most recent {@link stripImagesKeepRecent} has its image parts dropped
+     *  before the wire rebuild (image-only content collapses to an "[image]"
+     *  placeholder). Off by default — the #488 image floor / overflow 502 stays
+     *  the opt-in signal until this is enabled. */
     stripImages?: boolean;
     /** With {@link stripImages}, how many trailing messages keep their images
      *  verbatim (default 5). Ignored unless stripImages is true. */

src/server.ts

@@ -2,8 +2,7 @@ import http from "node:http";
 import fs from "node:fs";
 import { randomUUID } from "node:crypto";
 import { createCore, type CompressionCore, type CompressionState, type Config, type CoreMessage, type NudgeDecision, type Prompts, defaultPrompts, defaultCountTokens, estimateTokensFast, renderNudgeText, deactivateBlock, viableRanges } from "acp-kernel";
-import { resolveCompress, resolveCompressPrompts, resolveRequestConfig } from "./compress-settings.js";
-import { DEFAULT_STRIP_IMAGES_KEEP_RECENT, stripHistoricalImages } from "./strip-images.js";
+import { DEFAULT_STRIP_IMAGES_KEEP_RECENT, resolveCompress, resolveCompressPrompts, resolveRequestConfig } from "./compress-settings.js";
 import type { ProxyOptions } from "./config.js";
 import { loadOptions, loadRoutes } from "./config.js";
 import { resetProxyCache } from "./upstream-proxy.js";
@@ -13,14 +12,16 @@ import { codexAlignedWindow } from "./codex-models.js";
 import { fetchWithTimeout, MAX_REQUEST_BYTES } from "./fetch-util.js";
 import { formatUpstreamError, getUpstreamConnectionStatus, recordUpstreamConnection, resolveProxy, resolveProxyDecision, proxyDispatcher, type UpstreamProxyDecision } from "./upstream-proxy.js";
 import { maskHeaderForLog, maskHeadersForLog, maskHostPortForLog, maskUrlForLog, maskUrlsInText } from "./log-mask.js";
-// Protocol codecs live in the kernel now (single source of truth shared with
-// the omp/pi adapters): import from "acp-kernel/wire".
+// Protocol codecs + the historical-image strip primitive live in the kernel now
+// (single source of truth shared with the omp/pi adapters): import from
+// "acp-kernel/wire" (kernel #215).
 import {
     anthropicToCore,
     coreToAnthropic,
     conversationSignalAnthropic,
     extractSystem,
     buildSystem,
+    stripHistoricalImages,
     type AnthropicRequestBody,
 } from "acp-kernel/wire";
 import {

tests/strip-images.test.ts

@@ -1,6 +1,9 @@
 import test from "node:test";
 import assert from "node:assert/strict";
-import { DEFAULT_STRIP_IMAGES_KEEP_RECENT, stripHistoricalImages } from "../src/strip-images.ts";
+// The mechanism moved to acp-kernel's wire layer (kernel #215); these tests
+// stay as host-level regression coverage over the bundled kernel export.
+import { stripHistoricalImages } from "acp-kernel/wire";
+import { DEFAULT_STRIP_IMAGES_KEEP_RECENT } from "../src/compress-settings.ts";
 
 test("default keep-recent constant is 5", () => {
     assert.equal(DEFAULT_STRIP_IMAGES_KEEP_RECENT, 5);