diff --git a/docs/workbench-history.md b/docs/workbench-history.md
index 803353d..15b9375 100644
--- a/docs/workbench-history.md
+++ b/docs/workbench-history.md
@@ -153,3 +153,41 @@ Filtering uses the existing bounded metadata index and precedes twelve-row
 pagination. Corrupt indexes remain counted separately as unavailable; they are
 never treated as passed results. No report is opened, verification rerun, file
 pruned or apply capability created by a search.
+
+
+## Compare two saved verification records
+
+History now has independent earlier/later record selectors. Pick two verification
+records from their rows or enter their IDs, then compare. This reads their existing
+metadata and digest-bound bodies; it never calls the verifier, changes the current
+selection/baseline, consumes an approved plan or grants repair permission. Leaving
+the history view, changing an ID or cancelling discards obsolete replies while
+retaining the entered IDs and unrelated drafts. Comparisons use one bounded read
+slot; a second concurrent comparison receives a recoverable busy response.
+
+Both records must describe the same saved directory identity and verification
+mode. Skill reports require matching declared targets and complete, unsaturated
+comparison fields, consistent summaries and finding coverage, unique issue IDs and
+matching recorded exit codes. The same owner computes fresh-baseline and historical
+issue differences, including pairing changed evidence at the same code/location.
+The result distinguishes new, continuing, no-longer-observed and changed evidence;
+no-longer-observed findings are not certified fixes. Old reports do not record
+all tool/policy conditions, so identical selection is not a controlled regression.
+
+Artifact records retain the existing contract, declaration and receipt-bound
+comparison rules. Their finding counts stay separate from per-check changes.
+Different selections/contracts, incomplete or invalid evidence remain unavailable;
+they do not produce invented zero counts. Corrupt or changed stored bodies fail
+before comparison. Current source directories and contract files need not exist:
+this is an offline comparison of saved evidence, not a fresh physical-file check.
+
+POST `/api/history/compare` accepts `beforeId` and `afterId` under the existing
+loopback origin and session guards. History still caps state at 120 files/64 MiB,
+metadata at 16 KiB and each body at 8 MiB. Early row/field caps precede deep schema
+parsing; saturated 256-row/unknown evidence is unavailable. At most 32 code/count
+or reconciliation-index details reach the browser, with full accepted counts and
+explicit truncation. Raw finding messages, source paths, cells, recipes and backup
+paths are not returned. No history or receipt is rewritten.
+
+The workflow borrows [Qodana's baseline distinctions](https://www.jetbrains.com/help/qodana/baseline.html)
+while preserving this workbench's local, non-authenticated evidence boundary.
diff --git a/src/workbench/history.ts b/src/workbench/history.ts
index 19491f4..01c0811 100644
--- a/src/workbench/history.ts
+++ b/src/workbench/history.ts
@@ -4,6 +4,8 @@ import { isAbsolute, join } from "node:path";
 import { z } from "zod";
 import { parseStrictJson } from "../domain/strict-json.js";
 import { readDirectoryEntries, readWorkspaceText } from "../sandbox/workspace-tree.js";
+import {parseComparisonReport,compareVerificationReports} from "./verification-comparison.js";
+import {compareArtifactReports,parseArtifactReport} from "../domain/artifact-report-comparison.js";
 
 export const MAX_OUTPUT = 8 * 1024 * 1024;
 const MAX_META = 16 * 1024;
@@ -94,9 +96,40 @@ export class WorkbenchHistory {
   async read(id:unknown) {
     await this.entries();
     const record=await this.metadata(id);
+    return {record,output:await this.output(record)};
+  }
+  private async output(record:HistoryRecord) {
     const output=record.dataFile?await readWorkspaceText(join(this.root,record.dataFile),MAX_OUTPUT):undefined;
     if(output!==undefined && sha(output)!==record.dataSha256)throw new Error("历史材料摘要不匹配。");
-    return {record,output};
+    return output;
+  }
+  async compare(beforeId:unknown,afterId:unknown) {
+    const first=uuid.parse(beforeId),second=uuid.parse(afterId);
+    if(first===second)throw new WorkbenchStateError("请选择两份不同的历史记录。");
+    await this.entries();
+    const before=await this.metadata(first),after=await this.metadata(second);
+    const identity=(record:HistoryRecord)=>({id:record.id,createdAt:record.createdAt,reportSha256:record.dataSha256,exitCode:record.exitCode});
+    const base={schema:"skillsync.history-comparison/v1",before:identity(before),after:identity(after),kind:before.selection.kind,
+      readOnly:true,execution:"not-run",provenance:"not-authenticated"};
+    const unavailable=(reason:string)=>({...base,status:"unavailable" as const,reason});
+    if(before.kind!=="verify"||after.kind!=="verify")return unavailable("not-verification");
+    if(JSON.stringify(before.selection)!==JSON.stringify(after.selection))return unavailable("selection-changed");
+    // Scope predicates precede any body read. Do not reopen current source directories.
+    const left=await this.output(before),right=await this.output(after);
+    try {
+      if(before.selection.kind==="skill"){
+        const a=parseComparisonReport(parseStrictJson(left!)),b=parseComparisonReport(parseStrictJson(right!));
+        if(a.exitCode!==before.exitCode||b.exitCode!==after.exitCode)return unavailable("incomplete-evidence");
+        if(JSON.stringify(a.targets.map(row=>[row.name,row.scope,row.profileId]))!==JSON.stringify(b.targets.map(row=>[row.name,row.scope,row.profileId])))return unavailable("declared-targets-changed");
+        return {...base,...compareVerificationReports(a,b)};
+      }
+      const a=parseArtifactReport(parseStrictJson(left!)),b=parseArtifactReport(parseStrictJson(right!));
+      if(a.exitCode!==before.exitCode||b.exitCode!==after.exitCode)return unavailable("incomplete-evidence");
+      const compared=compareArtifactReports(a,b,before.dataSha256!);
+      if(compared.status!=="compared")return unavailable(compared.reason??"incomplete-evidence");
+      const details=(compared.checks??[]).filter(row=>row.change!=="unchanged").map(row=>({code:"reconciliation."+row.index,change:row.change,count:1}));
+      return {...base,status:"compared" as const,counts:compared.findings!,details:details.slice(0,32),detailsTotal:details.length,detailsTruncated:details.length>32};
+    }catch{return unavailable("invalid-evidence");}
   }
 }
 
diff --git a/src/workbench/page.ts b/src/workbench/page.ts
index 8041f8b..dec0d25 100644
--- a/src/workbench/page.ts
+++ b/src/workbench/page.ts
@@ -4,13 +4,13 @@ export function workbenchPage(nonce: string): string {
 <header><p class="product-name">SkillSync</p><h1>本机核验台</h1><p>打开 Skill 目录或交付包，查看核验结果、历史记录与修复计划。</p></header>
 <nav class="task-nav" aria-label="核验任务"><button id="nav-single" type="button" aria-controls="task-single" aria-pressed="true">单目录核验</button><button id="nav-batch" type="button" aria-controls="task-batch" aria-pressed="false">多批次验收</button><button id="nav-history" type="button" aria-controls="task-history" aria-pressed="false">历史记录</button></nav>
 <section id="task-batch" hidden aria-labelledby="batch-title"><h2 id="batch-title" tabindex="-1">验收多个交付</h2><p class="task-steps">预检计划 → 逐批核验 → 保存复核包</p><p>按计划只读核验多个交付；修正失败批次后保留已通过的证据。打开复核包只检查完整性，不重新核验原始数据或认证作者。</p><label for="batch-plan">验收计划文件</label><div class="row"><input id="batch-plan" autocomplete="off" placeholder="/project/acceptance-plan.json"><button id="choose-batch-plan" type="button">选择计划…</button></div><button id="batch-preview" type="button">预检验收计划</button><p id="batch-info" role="status"></p><label for="batch-output">新复核包文件</label><input id="batch-output" autocomplete="off"><label for="batch-previous">上次复核包（可选）</label><input id="batch-previous" autocomplete="off"><label><input id="batch-retry" type="checkbox">只重验失败或不完整批次，已通过输入必须保持不变</label><div class="row actions"><button class="primary" id="batch-run" type="button" disabled>执行并生成复核包</button></div><div id="batch-recovery" class="mode-help" hidden><h3>先核对此次输出</h3><p id="batch-recovery-state" role="status"></p><button id="batch-recover" type="button">检查此次输出包</button></div><hr><h3>查阅已保存的复核包</h3><p>此操作只读取已有证据，不重新核验原始文件。</p><label for="batch-package">复核包路径</label><div class="row"><input id="batch-package" autocomplete="off"><button id="choose-batch-package" type="button">选择复核包…</button></div><label for="batch-digest">预期 SHA-256（可选，来自独立可信来源，不会自动填入包自身摘要）</label><input id="batch-digest" autocomplete="off" maxlength="64"><label for="batch-contract">原契约路径（旧复核包必填，新包可选）</label><div class="row"><input id="batch-contract" autocomplete="off"><button id="choose-batch-contract" type="button">选择原契约…</button></div><button id="batch-open" type="button">打开并复核完整性</button><p id="batch-receipt" role="status"></p></section>
-<section id="task-history" hidden aria-labelledby="history-title"><h2 id="history-title" tabindex="-1">查看已存证据</h2><div class="history-filters"><label for="history-query">目录名包含</label><input id="history-query" maxlength="128" autocomplete="off" placeholder="只查目录名"><label for="history-kind">任务类型</label><select id="history-kind"><option value="">全部任务</option><option value="verify">核验</option><option value="plan">修复计划</option><option value="apply-intent">应用请求</option><option value="apply">应用回执</option></select><label for="history-exit">已记录的退出码</label><select id="history-exit"><option value="">全部结果</option><option value="0">0 · 正常完成</option><option value="1">1</option><option value="2">2</option><option value="3">3</option><option value="4">4</option></select><div class="row actions"><button id="history-filter" type="button">筛选记录</button><button id="history-clear" type="button">清除筛选</button></div></div><p id="history-info" role="status"></p><div id="history-list"></div><div class="row actions"><button id="history-prev" type="button" disabled>上一页</button><button id="history-next" type="button" disabled>下一页</button><button id="history-refresh" type="button">刷新</button></div><p>选择历史记录作为基线，再核验当前文件。历史记录只读，打开不会重新执行核验或授予修复权限。</p></section>
+<section id="task-history" hidden aria-labelledby="history-title"><h2 id="history-title" tabindex="-1">查看已存证据</h2><div class="history-filters"><label for="history-query">目录名包含</label><input id="history-query" maxlength="128" autocomplete="off" placeholder="只查目录名"><label for="history-kind">任务类型</label><select id="history-kind"><option value="">全部任务</option><option value="verify">核验</option><option value="plan">修复计划</option><option value="apply-intent">应用请求</option><option value="apply">应用回执</option></select><label for="history-exit">已记录的退出码</label><select id="history-exit"><option value="">全部结果</option><option value="0">0 · 正常完成</option><option value="1">1</option><option value="2">2</option><option value="3">3</option><option value="4">4</option></select><div class="row actions"><button id="history-filter" type="button">筛选记录</button><button id="history-clear" type="button">清除筛选</button></div></div><p id="history-info" role="status"></p><div id="history-list"></div><div class="row actions"><button id="history-prev" type="button" disabled>上一页</button><button id="history-next" type="button" disabled>下一页</button><button id="history-refresh" type="button">刷新</button></div><p>选择历史记录作为基线，再核验当前文件。历史记录只读，打开不会重新执行核验或授予修复权限。</p><div class="history-comparison" role="region" aria-labelledby="history-compare-title"><h3 id="history-compare-title">比较两份已存核验</h3><p>在记录旁选择较早、较晚的核验，或输入两份记录编号。不会重新运行核验，也不改变当前修复计划。</p><label for="history-compare-before">较早记录编号</label><input id="history-compare-before" maxlength="36" autocomplete="off" spellcheck="false"><label for="history-compare-after">较晚记录编号</label><input id="history-compare-after" maxlength="36" autocomplete="off" spellcheck="false"><div class="row actions"><button id="history-compare" type="button">比较已存记录</button><button id="history-compare-cancel" type="button" hidden>取消历史对照</button></div><p id="history-compare-info" role="status"></p><div id="history-compare-result" hidden></div><p>仅对照保存的证据；较晚记录未出现某项，不代表当前目录已经修复。报告未完整记录工具与策略条件，不能据此授予执行或修复权限。</p></div></section>
 <section id="task-single" aria-labelledby="selection"><h2 id="selection" tabindex="-1">核验一个目录</h2><p class="task-steps">选择目录与范围 → 核验 → 查看结果</p><label for="root" id="root-label">Skill 根目录或包含 Skills 的目录</label><div class="row"><input id="root" name="root" aria-describedby="mode-help root-error" placeholder="/path/to/skill…" autocomplete="off"><button id="choose" type="button">选择目录…</button></div><p id="root-error" class="field-error" role="alert"></p><fieldset class="selection-options"><legend>选择要完成的任务</legend><label><input id="mode-skill" name="verification-kind" type="radio" value="skill" checked><span><strong>检查一个 Skill</strong><small>检查结构、兼容性与声明；可继续审阅处理计划</small></span></label><label><input id="mode-artifacts" name="verification-kind" type="radio" value="artifacts"><span><strong>验收交付文件</strong><small>对照清单核对文件与数据，保留只读证据</small></span></label></fieldset><input id="kind" type="hidden" value="skill"><p id="mode-help" class="mode-help"></p><div id="contract-fields" hidden><label for="contract">验收清单路径（YAML / JSON）</label><div class="row"><input id="contract" name="contract" aria-describedby="contract-error" autocomplete="off"><button id="choose-contract" type="button">选择清单…</button></div><p id="contract-error" class="field-error" role="alert"></p><label><input id="delivery" type="checkbox">按 SkillTape 交付清单核验（delivery.json）</label></div><div class="row actions"><button class="primary" id="verify" type="button">核验目录</button></div></section>
 <div class="operation-status"><p id="status" role="status" aria-live="polite">尚未核验</p><button id="cancel" type="button" disabled>取消当前核验</button></div><section id="result" hidden aria-labelledby="result-title"><h2 id="result-title" tabindex="-1">核验结果与证据</h2><div id="task-summary" class="result-summary" aria-labelledby="summary-title"><h3 id="summary-title"></h3><p id="summary-next" role="status"></p><ul id="summary-counts"></ul><div class="row actions"><button id="plan" type="button" hidden>生成处理计划</button><button id="result-recheck" type="button">重新核验当前文件</button><button id="result-details" type="button">查看报告明细</button></div></div><p id="comparison" role="status"></p><button id="export-summary" type="button" disabled>导出摘要</button><iframe id="report" title="核验报告" sandbox=""></iframe></section>
 <section id="fix" hidden aria-labelledby="fix-title"><h2 id="fix-title" tabindex="-1">审阅修复计划</h2><pre id="changes"></pre><label><input id="confirm" type="checkbox">我已审阅，应用以上安全修复并保留备份</label><div class="row actions"><button id="apply" type="button" disabled>应用并备份</button><button id="reverify" type="button">重新核验</button></div><p id="receipt"></p></section><footer><p>只检查本机文件，不运行 Skill。</p><details><summary>报告保存位置</summary><p>报告、计划和回执保存在本机私有目录；历史功能启用前的文件仍保留。</p></details></footer></main><script src="/app.js"></script></body></html>`;
 }
 
-export const workbenchStyle = `:root{font:16px/1.6 system-ui;color:#19343c;background:#f3f6f6}*{box-sizing:border-box}main{max-width:1040px;margin:auto;padding:32px 20px}header{margin-bottom:28px}h1{margin:8px 0;font-size:28px;line-height:1.2}h3{font-size:17px}.product-name{font-weight:750;letter-spacing:-.02em;margin:0}.task-nav{display:flex;flex-wrap:wrap;gap:8px;padding-bottom:16px;border-bottom:1px solid #c8d8dc}.task-nav button[aria-pressed=true]{color:white;background:#235661;border-color:#235661}.primary{color:white;background:#235661;border-color:#235661}.task-steps{color:#496771;font-size:14px}.skip-link{position:absolute;top:-100px;padding:12px;background:white;color:#19343c}.skip-link:focus{top:8px;z-index:10}h2[tabindex],main{scroll-margin-top:16px}h2[tabindex]:focus{outline:3px solid #087a91;outline-offset:5px}hr{border:0;border-top:1px solid #c8d8dc;margin:28px 0}h2{font-size:20px}section{padding:20px;background:white;border:1px solid #c8d8dc;border-radius:8px;margin:20px 0}label{display:block;margin:12px 0 6px}input:not([type=checkbox]),select{font:inherit;min-height:44px;padding:8px;width:100%;border:1px solid #829fa7;border-radius:4px}input[type=checkbox]{width:24px;height:24px;vertical-align:middle;margin-right:8px}label:has(input[type=checkbox]){min-height:44px;display:flex;align-items:center}button{font:inherit;min-height:44px;padding:8px 18px;border:1px solid #6f939d;border-radius:4px;color:#19343c;background:#edf5f6;cursor:pointer}button:disabled{opacity:.55;cursor:default}.row{display:flex;gap:12px;align-items:center}.row input{flex:1;min-width:0}.row button{white-space:nowrap}.actions{flex-wrap:wrap;margin-top:18px}:focus-visible{outline:3px solid #087a91;outline-offset:3px}iframe{width:100%;height:580px;border:1px solid #c8d8dc;margin-bottom:16px}pre{white-space:pre-wrap;overflow-wrap:anywhere;font:14px/1.7 ui-monospace,monospace}#history-list p,#batch-receipt,#batch-info{overflow-wrap:anywhere}footer{font-size:13px;color:#496771}footer p{margin:8px 0}summary{cursor:pointer;min-height:44px;padding:8px 0}.operation-status{display:flex;align-items:center;justify-content:space-between;gap:12px}.operation-status button{flex-shrink:0}.operation-status p{overflow-wrap:anywhere}#status{padding:12px;border-left:3px solid #318496}[hidden]{display:none!important}.selection-options{border:0;padding:0;display:grid;grid-template-columns:1fr 1fr;gap:12px}.selection-options label{display:flex;align-items:flex-start;gap:10px;border:1px solid #c8d8dc;border-radius:6px;padding:14px;margin:0}.selection-options label:has(input:checked){border-color:#235661;background:#edf5f6}.selection-options input[type=radio]{width:22px;min-height:22px;flex:0 0 22px}.selection-options small{display:block;color:#496771}.field-error{color:#9c2f35}.mode-help{background:#edf5f6;padding:12px}.result-summary{border-left:3px solid #318496;padding:4px 16px;margin:16px 0}.result-summary ul{display:flex;gap:18px;flex-wrap:wrap;padding-left:20px}.result-summary .actions{margin-bottom:16px}@media(max-width:580px){.selection-options{grid-template-columns:1fr}}@media(max-width:580px){.operation-status{align-items:flex-start;flex-direction:column}.row{flex-wrap:wrap}.row input{flex-basis:100%}main{padding:16px}section{padding:16px}}`;
+export const workbenchStyle = `:root{font:16px/1.6 system-ui;color:#19343c;background:#f3f6f6}*{box-sizing:border-box}main{max-width:1040px;margin:auto;padding:32px 20px}header{margin-bottom:28px}h1{margin:8px 0;font-size:28px;line-height:1.2}h3{font-size:17px}.product-name{font-weight:750;letter-spacing:-.02em;margin:0}.task-nav{display:flex;flex-wrap:wrap;gap:8px;padding-bottom:16px;border-bottom:1px solid #c8d8dc}.task-nav button[aria-pressed=true]{color:white;background:#235661;border-color:#235661}.primary{color:white;background:#235661;border-color:#235661}.task-steps{color:#496771;font-size:14px}.skip-link{position:absolute;top:-100px;padding:12px;background:white;color:#19343c}.skip-link:focus{top:8px;z-index:10}h2[tabindex],main{scroll-margin-top:16px}h2[tabindex]:focus{outline:3px solid #087a91;outline-offset:5px}hr{border:0;border-top:1px solid #c8d8dc;margin:28px 0}h2{font-size:20px}section{padding:20px;background:white;border:1px solid #c8d8dc;border-radius:8px;margin:20px 0}label{display:block;margin:12px 0 6px}input:not([type=checkbox]),select{font:inherit;min-height:44px;padding:8px;width:100%;border:1px solid #829fa7;border-radius:4px}input[type=checkbox]{width:24px;height:24px;vertical-align:middle;margin-right:8px}label:has(input[type=checkbox]){min-height:44px;display:flex;align-items:center}button{font:inherit;min-height:44px;padding:8px 18px;border:1px solid #6f939d;border-radius:4px;color:#19343c;background:#edf5f6;cursor:pointer}button:disabled{opacity:.55;cursor:default}.row{display:flex;gap:12px;align-items:center}.row input{flex:1;min-width:0}.row button{white-space:nowrap}.actions{flex-wrap:wrap;margin-top:18px}:focus-visible{outline:3px solid #087a91;outline-offset:3px}iframe{width:100%;height:580px;border:1px solid #c8d8dc;margin-bottom:16px}pre{white-space:pre-wrap;overflow-wrap:anywhere;font:14px/1.7 ui-monospace,monospace}#history-list p,#batch-receipt,#batch-info{overflow-wrap:anywhere}footer{font-size:13px;color:#496771}footer p{margin:8px 0}summary{cursor:pointer;min-height:44px;padding:8px 0}.operation-status{display:flex;align-items:center;justify-content:space-between;gap:12px}.operation-status button{flex-shrink:0}.operation-status p{overflow-wrap:anywhere}#status{padding:12px;border-left:3px solid #318496}[hidden]{display:none!important}.selection-options{border:0;padding:0;display:grid;grid-template-columns:1fr 1fr;gap:12px}.selection-options label{display:flex;align-items:flex-start;gap:10px;border:1px solid #c8d8dc;border-radius:6px;padding:14px;margin:0}.selection-options label:has(input:checked){border-color:#235661;background:#edf5f6}.selection-options input[type=radio]{width:22px;min-height:22px;flex:0 0 22px}.selection-options small{display:block;color:#496771}.field-error{color:#9c2f35}.mode-help{background:#edf5f6;padding:12px}.result-summary{border-left:3px solid #318496;padding:4px 16px;margin:16px 0}.result-summary ul{display:flex;gap:18px;flex-wrap:wrap;padding-left:20px}.result-summary .actions{margin-bottom:16px}@media(max-width:580px){.selection-options{grid-template-columns:1fr}}@media(max-width:580px){.operation-status{align-items:flex-start;flex-direction:column}.row{flex-wrap:wrap}.row input{flex-basis:100%}main{padding:16px}section{padding:16px}}.history-comparison{margin-top:24px;padding-top:20px;border-top:1px solid #c8d8dc}.history-comparison-counts{display:flex;gap:20px;flex-wrap:wrap}.history-comparison-counts div{min-width:100px}.history-comparison-counts dt{font-size:14px}.history-comparison-counts dd{font-size:24px;margin:4px 0}.history-comparison code{overflow-wrap:anywhere}#history-list button{margin:4px}.history-comparison ul{padding-left:20px}`;
 
 export const workbenchScript = `"use strict";
 const $ = id => document.getElementById(id);
@@ -18,19 +18,20 @@ const nonce = document.querySelector('meta[name="client"]').content;
 let busy = false, planId = null, selected = null, baselineId = null, historyId = null, historyOffset = 0, historyTotal = 0, historyLoading = false, historyRefreshQueued = false, renderedHistory = null, batchReady=false, summaryCanPlan=false, recoveryPath=null;
 // Switching tasks hides existing controls; it never replaces form nodes or submits them.
 let historyFilters={query:''};
+let historyCompareController=null,historyCompareSerial=0,historyCompareLoading=false;
 let activeTask='single', resultOwner='single', resultAvailable=false, fixAvailable=false;
 function syncWorkspace(){
  for(const task of ['single','batch','history']){ $('task-'+task).hidden=task!==activeTask; $('nav-'+task).setAttribute('aria-pressed',String(task===activeTask)); }
  $('result').hidden=!resultAvailable||resultOwner!==activeTask;
  $('fix').hidden=!fixAvailable||activeTask!=='single';
 }
-function setTask(task){activeTask=task;syncWorkspace();if(!$('result').hidden&&reportHtml)mountReport();$(task==='single'?'selection':task==='batch'?'batch-title':'history-title').focus();}
+function setTask(task){if(activeTask==='history'&&task!=='history')clearHistoryComparison();activeTask=task;syncWorkspace();if(!$('result').hidden&&reportHtml)mountReport();$(task==='single'?'selection':task==='batch'?'batch-title':'history-title').focus();}
 function revealResult(owner){resultOwner=owner;resultAvailable=true;syncWorkspace();if(activeTask===owner)$('result-title').focus();}
 function hideResult(){resultAvailable=false;syncWorkspace();}
 function setFix(visible){fixAvailable=visible;syncWorkspace();}
 for(const task of ['single','batch','history'])$('nav-'+task).onclick=()=>setTask(task);
-async function api(action, body = {}) {
- let response; try { response = await fetch('/api/' + action, {method:'POST',headers:{'Content-Type':'application/json','X-SkillSync-Client':nonce},body:JSON.stringify(body)}); }
+async function api(action, body = {}, signal) {
+ let response; try { response = await fetch('/api/' + action, {method:'POST',headers:{'Content-Type':'application/json','X-SkillSync-Client':nonce},body:JSON.stringify(body),signal}); }
  catch { throw new Error('无法连接本机服务，请确认核验台已启动后重试。'); }
  let data; try { data = await response.json(); } catch { throw new Error('服务响应不完整，请重新打开核验台后重试。'); }
  if(response.status===403) throw new Error('核验台会话已失效，请重新打开页面后重试。');
@@ -45,7 +46,7 @@ function mountReport(){
 function showReport(html){reportHtml=html.replaceAll('href="#','href="about:srcdoc#');if(!$('result').hidden)mountReport();}
 function clearReport(){summaryCanPlan=false;if(!reportHtml)return;reportHtml='';$('report').srcdoc='';}
 function status(text){ $('status').textContent = text; }
-function lock(value, applying = false){ busy=value; ['verify','plan','result-recheck','result-details','mode-skill','mode-artifacts','reverify','choose','choose-contract','root','contract','kind','delivery','history-refresh','batch-plan','batch-preview','batch-recover','batch-output','batch-previous','batch-retry','batch-package','batch-digest','batch-open','choose-batch-plan','choose-batch-package'].forEach(id => $(id).disabled=value); $('batch-run').disabled=value||!batchReady; document.querySelectorAll('.history-open').forEach(button=>button.disabled=value||historyLoading); ['history-query','history-kind','history-exit','history-filter','history-clear','history-refresh'].forEach(id=>$(id).disabled=value||historyLoading); $('history-prev').disabled=value||historyLoading||historyOffset===0; $('history-next').disabled=value||historyLoading||historyOffset+12>=historyTotal; $('export-summary').disabled=value||!historyId; $('cancel').disabled=!value || applying; $('confirm').disabled=value||!planId; $('apply').disabled=value || !$('confirm').checked || !planId; $('plan').disabled=value||!selected||!summaryCanPlan; }
+function lock(value, applying = false){ busy=value; ['verify','plan','result-recheck','result-details','mode-skill','mode-artifacts','reverify','choose','choose-contract','root','contract','kind','delivery','history-refresh','batch-plan','batch-preview','batch-recover','batch-output','batch-previous','batch-retry','batch-package','batch-digest','batch-open','choose-batch-plan','choose-batch-package'].forEach(id => $(id).disabled=value); $('batch-run').disabled=value||!batchReady; document.querySelectorAll('.history-open').forEach(button=>button.disabled=value||historyLoading); ['history-query','history-kind','history-exit','history-filter','history-clear','history-refresh'].forEach(id=>$(id).disabled=value||historyLoading); $('history-prev').disabled=value||historyLoading||historyOffset===0; $('history-next').disabled=value||historyLoading||historyOffset+12>=historyTotal; $('export-summary').disabled=value||!historyId; $('cancel').disabled=!value || applying; $('confirm').disabled=value||!planId; $('apply').disabled=value || !$('confirm').checked || !planId; $('plan').disabled=value||!selected||!summaryCanPlan; syncHistoryCompareControls(); document.querySelectorAll('.history-compare-pick').forEach(button=>button.disabled=value||historyLoading); }
 function clearPlan(){$('fix-title').textContent='审阅修复计划';planId=null;$('confirm').checked=false;setFix(false);$('changes').textContent='';$('apply').disabled=true;}
 function invalidate(){ $('plan').disabled=true;$('plan').hidden=true;fieldError('root','');fieldError('contract','');selected=null; planId=null; baselineId=null; historyId=null; $('comparison').textContent=''; $('export-summary').disabled=true; hideResult(); setFix(false); $('confirm').checked=false; clearReport(); status('目录或模式已更改，请重新核验'); }
 ['root','contract'].forEach(id=>$(id).addEventListener('input',()=>{invalidate();syncMode();}));
@@ -75,6 +76,42 @@ $('apply').onclick=async()=>{
  catch(e){$('receipt').textContent=e.message;showTaskSummary({title:'应用结果待核对',description:'原计划已失效。请查看保存的回执或重新核验当前目录，不要重复应用旧计划。',counts:[],canPlan:false});status(e.message+'；请重新核验当前目录');}
  finally{lock(false);}
 };
+
+function syncHistoryCompareControls(){
+ $('history-compare').disabled=busy||historyCompareLoading;
+ $('history-compare-before').disabled=busy;$('history-compare-after').disabled=busy;
+ $('history-compare-cancel').hidden=!historyCompareLoading;
+}
+function clearHistoryComparison(){
+ historyCompareController?.abort();historyCompareController=null;historyCompareSerial++;historyCompareLoading=false;
+ $('history-compare-info').textContent='';$('history-compare-result').replaceChildren();$('history-compare-result').hidden=true;syncHistoryCompareControls();
+}
+const historyReasons={'not-verification':'只比较已存核验报告，计划或应用回执不能替代核验结果。','selection-changed':'两份记录的目录或核验方式不同，不能按同一范围对照。','declared-targets-changed':'两份报告声明的核验目标不同。','incomplete-evidence':'证据不完整或达到容量上限，没有生成零变化结论。','invalid-evidence':'历史报告结构或记录关联无效，原材料保留。','contract-changed':'契约摘要缺失或不同，不能按相同声明对照。','check-declarations-changed':'两份交付报告声明的检查项不同。'};
+const historyChangeLabels={added:'新增',ongoing:'仍存在',resolved:'较晚记录未出现',changed:'同类证据变化',improved:'记录检查改善',regressed:'记录检查回退'};
+function renderHistoryComparison(data,before,after){
+ if(!data||data.schema!=='skillsync.history-comparison/v1'||data.before?.id!==before||data.after?.id!==after||data.readOnly!==true||data.execution!=='not-run'||data.provenance!=='not-authenticated'||!['skill','artifacts'].includes(data.kind))throw new Error('历史对照响应不完整，请重新选择两份记录。');
+ if(data.status==='unavailable'){$('history-compare-info').textContent='历史记录不可比较：'+(historyReasons[data.reason]||'材料无法完整比较，请检查两份原记录。');return;}
+ const keys=data.kind==='skill'?['added','ongoing','resolved','changed']:['added','ongoing','resolved'];
+ if(data.status!=='compared'||!data.counts||!keys.every(key=>Number.isSafeInteger(data.counts[key])&&data.counts[key]>=0&&data.counts[key]<=256)||!Array.isArray(data.details)||data.details.length>32||!Number.isSafeInteger(data.detailsTotal)||data.detailsTotal<0||data.detailsTotal>512||data.details.length!==Math.min(data.detailsTotal,32)||data.detailsTruncated!==(data.detailsTotal>data.details.length)||data.details.some(row=>!row||typeof row.code!=='string'||row.code.length>128||!/^[A-Za-z0-9][A-Za-z0-9._:-]*$/.test(row.code)||!Object.hasOwn(historyChangeLabels,row.change)||!Number.isSafeInteger(row.count)||row.count<1||row.count>256))throw new Error('历史对照响应不完整，请重新选择两份记录。');
+ const result=$('history-compare-result'),summary=document.createElement('dl');summary.className='history-comparison-counts';
+ for(const key of keys){const row=document.createElement('div'),name=document.createElement('dt'),value=document.createElement('dd');name.textContent=historyChangeLabels[key];value.textContent=String(data.counts[key]);row.append(name,value);summary.append(row);}result.append(summary);
+ if(data.details.length){const list=document.createElement('ul');for(const item of data.details){const row=document.createElement('li'),code=document.createElement('code'),text=document.createElement('span');code.textContent=item.code;text.textContent=' · '+historyChangeLabels[item.change]+' · '+item.count;row.append(code,text);list.append(row);}result.append(list);}
+ if(data.detailsTruncated){const note=document.createElement('p');note.textContent='显示 '+data.details.length+'/'+data.detailsTotal+' 类明细，汇总仍覆盖已接受的完整范围。';result.append(note);}
+ result.hidden=false;$('history-compare-info').textContent='历史证据对照已完成；没有重新核验当前目录。';
+}
+$('history-compare').onclick=async()=>{
+ if(busy||historyCompareLoading)return;
+ clearHistoryComparison();const before=$('history-compare-before').value.trim(),after=$('history-compare-after').value.trim();
+ const uuid=/^[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}$/i;
+ if(!uuid.test(before)||!uuid.test(after)||before===after){$('history-compare-info').textContent='请选择两份不同的有效历史记录编号。';return;}
+ const serial=historyCompareSerial,controller=new AbortController();historyCompareController=controller;historyCompareLoading=true;syncHistoryCompareControls();$('history-compare-info').textContent='正在只读核对两份历史材料…';
+ try{const data=await api('history/compare',{beforeId:before,afterId:after},controller.signal);if(serial===historyCompareSerial&&!controller.signal.aborted)renderHistoryComparison(data,before,after);}
+ catch(error){if(serial===historyCompareSerial&&!controller.signal.aborted)$('history-compare-info').textContent=error.message;}
+ finally{if(serial===historyCompareSerial){historyCompareController=null;historyCompareLoading=false;syncHistoryCompareControls();}}
+};
+$('history-compare-cancel').onclick=()=>{clearHistoryComparison();$('history-compare-info').textContent='已取消历史对照，原记录未改变。';};
+for(const name of ['before','after']){const field=$('history-compare-'+name);field.addEventListener('input',clearHistoryComparison);field.addEventListener('keydown',event=>{if(event.key==='Enter'){event.preventDefault();$('history-compare').click();}});}
+
 function showComparison(value){ $('comparison').textContent=!value?'此次结果可作为后续复查基线。':value.status==='compared'?'与基线相比：新增 '+value.added+' · 仍然存在 '+value.ongoing+' · 证据变化 '+(value.changed||0)+' · 本次不再出现 '+value.resolved:'基线无法比较：范围已变化或证据不完整。'; }
 function showHistoryFilters(){ $('history-query').value=historyFilters.query; $('history-kind').value=historyFilters.kind||''; $('history-exit').value=historyFilters.exitCode===undefined?'':String(historyFilters.exitCode); }
 async function loadHistory(newest=false, filters=historyFilters, offset=newest?0:historyOffset){
@@ -85,7 +122,9 @@ async function loadHistory(newest=false, filters=historyFilters, offset=newest?0
  for(const item of data.items){const row=document.createElement('p'), label=document.createElement('span'), button=document.createElement('button');
  label.textContent=new Date(item.createdAt).toLocaleString()+' · '+({verify:'核验',plan:'修复计划','apply-intent':'应用请求',apply:'应用回执'}[item.kind])+' · '+item.label+' '; button.type='button';button.className='history-open';button.textContent=item.kind==='verify'?'查看并设为基线':'查看'; button.disabled=busy||historyLoading;
  button.onclick=async()=>{lock(true,true);try{const data=await api('history/open',{id:item.id}); selected=null;planId=null;baselineId=data.baselineId||null;historyId=data.id;$('root').value=data.selection.path;$('kind').value=data.selection.kind;$('contract').value=data.selection.contract||'';$('delivery').checked=data.selection.delivery;syncMode();$('confirm').checked=false;setFix(false);$('plan').hidden=true;revealResult('history');showReport(data.html);showComparison(data.comparison);showTaskSummary(data.summary);status('正在查看历史记录；点击“核验目录”检查当前文件。');}catch(e){status(e.message);}finally{lock(false);}};
- row.append(label,button);$('history-list').append(row);}
+ row.setAttribute('data-history-id',item.id);row.append(label,button);
+ if(item.kind==='verify')for(const [side,text]of [['before','设为较早'],['after','设为较晚']]){const pick=document.createElement('button');pick.type='button';pick.className='history-compare-pick';pick.textContent=text;pick.disabled=busy||historyLoading;pick.setAttribute('aria-label','将记录 '+item.id+' '+text);pick.onclick=()=>{$('history-compare-'+side).value=item.id;clearHistoryComparison();};row.append(pick);}
+ $('history-list').append(row);}
  renderedHistory=signature; }
  $('history-info').textContent=data.total+' 条匹配记录 · 保存文件 '+data.capacity.files+'/'+data.capacity.maxFiles+(data.unavailable?' · '+data.unavailable+' 条索引无法读取（不参与筛选）':'');
  $('history-prev').disabled=busy||historyOffset===0;$('history-next').disabled=busy||historyOffset+12>=historyTotal;
diff --git a/src/workbench/server.ts b/src/workbench/server.ts
index fe00700..95be5f4 100644
--- a/src/workbench/server.ts
+++ b/src/workbench/server.ts
@@ -17,7 +17,7 @@ import { journeySummary } from "./journey-summary.js";
 import { workbenchPage, workbenchScript, workbenchStyle } from "./page.js";
 import { exportHistorySummary, MAX_OUTPUT, WorkbenchHistory, WorkbenchStateError, type HistoryComparison, type Selection } from "./history.js";
 import { parseStrictJson } from "../domain/strict-json.js";
-import { compareIssues } from "../domain/baseline.js";
+import {compareVerificationReports} from "./verification-comparison.js";
 import { compareArtifactReports, parseArtifactReport } from "../domain/artifact-report-comparison.js";
 import {previewAcceptancePlan,inspectAcceptancePackage,batchSummary} from "../cli/commands/batch.js";
 import {renderBatchHtml} from "../reporters/batch-html.js";
@@ -38,6 +38,7 @@ export async function startWorkbench(options: { port?: number; stateDir: string;
   const nonce = randomBytes(32).toString("hex");
   const cliPath = options.cliPath ?? fileURLToPath(new URL("../cli/index.js", import.meta.url));
   let active: ChildProcess | undefined, busy = false, applying = false, cancelled = false;
+  let comparingHistory=false;
   let selection: Selection | undefined;
   let actionable: string[] = [];
   let plan: { id: string; path: string; value: ActionPlan; snapshot: string; historyId:string } | undefined;
@@ -105,6 +106,13 @@ export async function startWorkbench(options: { port?: number; stateDir: string;
       if (req.url === "/api/history") return send(res,200,await history.list(input.offset===undefined?0:Number(input.offset),{
         query:input.query??"",kind:input.kind,exitCode:input.exitCode,
       }));
+      if(req.url==="/api/history/compare"){
+        if(comparingHistory)return send(res,409,{error:"已有历史对照读取中，请稍后重试。"});
+        comparingHistory=true;
+        try{return send(res,200,await history.compare(input.beforeId,input.afterId));}
+        catch(error){return send(res,400,{error:error instanceof WorkbenchStateError?error.message:"历史材料无法稳定读取，请检查两份原记录；没有重新执行核验。"});}
+        finally{comparingHistory=false;}
+      }
       if (busy) return send(res, 409, {error: "已有操作进行中。"});
       busy = true; cancelled = false;
       try {
@@ -202,18 +210,9 @@ export async function startWorkbench(options: { port?: number; stateDir: string;
             if(selected.kind==="artifacts") {
               const compared=compareArtifactReports(baseline.report as ArtifactReport,parseArtifactReport(report),baseline.digest);
               comparison=compared.status==="compared"?{status:"compared",added:compared.findings!.added,ongoing:compared.findings!.ongoing,resolved:compared.findings!.resolved}:{status:"unavailable",reason:compared.reason};
-            } else if([baseline.report.exitCode,report.exitCode].some(c=>c===2||c===4)||[(baseline.report as VerificationReport).issues,report.issues].some(v=>v.length>=256))comparison={status:"unavailable",reason:"incomplete-evidence"};
-            else {
-              const pending=(value:VerificationReport)=>value.issues.filter(issue=>issue.finding.status==="fail"||issue.finding.status==="warn");
-              const before=pending(baseline.report as VerificationReport),after=pending(report),c=compareIssues(before,after);
-              // A warning may bind the entire Skill digest. Pair changed evidence
-              // within the same code/location, rather than claiming it was fixed.
-              const group=(issue:VerificationReport["issues"][number])=>JSON.stringify([issue.finding.code,issue.finding.skill,issue.finding.target,issue.location]);
-              const removed=new Map<string,number>();
-              for(const issue of before.filter(i=>c.resolvedIds.includes(i.id)))removed.set(group(issue),(removed.get(group(issue))??0)+1);
-              let changed=0;
-              for(const issue of after.filter(i=>c.newIds.includes(i.id))) {const key=group(issue),count=removed.get(key)??0;if(count){changed++;removed.set(key,count-1);}}
-              comparison={status:"compared",added:c.newIds.length-changed,ongoing:c.ongoingIds.length,resolved:c.resolvedIds.length-changed,changed};
+            } else {
+              const compared=compareVerificationReports(baseline.report as VerificationReport,report);
+              comparison=compared.status==='compared'?{status:'compared',...compared.counts}:{status:'unavailable',reason:compared.reason};
             }
           }
           const saved=await history.append({kind:"verify",selection:selected,snapshot,baselineId:baseline?.id,parentId:latestId,exitCode:report.exitCode,comparison},output);
diff --git a/src/workbench/verification-comparison.ts b/src/workbench/verification-comparison.ts
new file mode 100644
index 0000000..613929c
--- /dev/null
+++ b/src/workbench/verification-comparison.ts
@@ -0,0 +1,67 @@
+import {z} from "zod";
+import type {VerificationReport} from "../cli/commands/verify.js";
+import {compareIssues} from "../domain/baseline.js";
+import {issueIdForFinding} from "../domain/issue.js";
+import {FindingSchema} from "../domain/result.js";
+
+export type IssueCounts={added:number;ongoing:number;resolved:number;changed:number};
+export type ComparisonDetail={code:string;change:string;count:number};
+type Report=Pick<VerificationReport,"issues"|"findings"|"summary"|"exitCode">;
+const text=z.string().min(1).max(4096);
+const finding=FindingSchema.refine(row=>row.code.length<=128&&/^[A-Za-z0-9][A-Za-z0-9._:-]*$/.test(row.code)
+ &&row.skill.length<=4096&&(row.target?.length??0)<=4096&&row.message.length<=4096&&(row.remediation?.length??0)<=4096
+ &&row.evidence.length<=256&&row.evidence.every(item=>Object.keys(item).length<=32&&Object.values(item).every(value=>value.length<=4096)));
+const count=z.number().int().min(0).max(256);
+const schema=z.object({schema_version:z.literal(1),generated_at:z.string().datetime(),
+ targets:z.array(z.object({name:text,path:text,scope:z.enum(["explicit","project","user"]),profileId:text.optional()})).min(1).max(64),
+ findings:z.array(finding).max(256),issues:z.array(z.object({id:z.string().regex(/^iss_[a-f0-9]{64}$/),
+ state:z.enum(["open","acknowledged","resolved","ignored","regressed"]),finding,
+ location:z.object({path:text,line:z.number().int().nonnegative().safe().optional()}).passthrough().optional(),
+ })).max(256),summary:z.object({total:count,pass:count,warn:count,fail:count,unknown:count}).strict(),
+ exitCode:z.union([z.literal(0),z.literal(1),z.literal(2),z.literal(3),z.literal(4)]),
+});
+
+/** Validate comparison fields; unused explanations/repair recipes are never consumed. */
+export function parseComparisonReport(value:unknown) {
+ // Zod arrays collect child errors even after max() fails. Reject hostile widths
+ // before deep parsing, while the 8 MiB history reader remains the byte bound.
+ const object=(v:unknown):v is Record<string,unknown>=>Boolean(v&&typeof v==="object"&&!Array.isArray(v));
+ if(!object(value)||Object.keys(value).length>16||!Array.isArray(value.targets)||value.targets.length>64
+  ||value.targets.some(row=>!object(row)||Object.keys(row).length>8)
+  ||!Array.isArray(value.findings)||value.findings.length>256||!Array.isArray(value.issues)||value.issues.length>256)throw new Error("History capacity");
+ const candidates=[...value.findings,...value.issues.map(row=>object(row)?row.finding:undefined)];
+ if(candidates.some(row=>!object(row)||Object.keys(row).length>16||!Array.isArray(row.evidence)||row.evidence.length>256
+  ||row.evidence.some(item=>!object(item)||Object.keys(item).length>32||Object.values(item).some(v=>typeof v!=="string"||v.length>4096))))throw new Error("History evidence capacity");
+ const parsed=schema.parse(value);
+ const actual={total:parsed.findings.length,pass:0,warn:0,fail:0,unknown:0};
+ for(const item of parsed.findings)actual[item.status]++;
+ const expected=new Set(parsed.findings.map(item=>issueIdForFinding(item))),observed=new Set(parsed.issues.map(item=>issueIdForFinding(item.finding)));
+ if(Object.keys(actual).some(key=>actual[key as keyof typeof actual]!==parsed.summary[key as keyof typeof actual])
+  ||new Set(parsed.issues.map(item=>item.id)).size!==parsed.issues.length||expected.size!==observed.size||[...expected].some(key=>!observed.has(key)))throw new Error("Incomplete history findings");
+ return parsed;
+}
+
+type Compared={status:"compared";counts:IssueCounts;details:ComparisonDetail[];detailsTotal:number;detailsTruncated:boolean};
+type Unavailable={status:"unavailable";reason:"incomplete-evidence"};
+type NeededReport=Pick<Report,"findings"|"summary"|"exitCode">&{issues:Array<Pick<Report["issues"][number],"id"|"finding"|"location">>};
+
+/** Same owner for fresh/baseline and saved/saved comparisons. No raw messages or paths leave it. */
+export function compareVerificationReports(before:NeededReport,after:NeededReport):Compared|Unavailable {
+ if([before,after].some(report=>report.exitCode===2||report.exitCode===4||report.issues.length>=256||report.findings.length>=256||report.summary.unknown>0))return {status:"unavailable",reason:"incomplete-evidence"};
+ const pending=(report:NeededReport)=>report.issues.filter(issue=>issue.finding.status==="fail"||issue.finding.status==="warn");
+ const left=pending(before),right=pending(after),comparison=compareIssues(left,right);
+ const added=new Set(comparison.newIds),absent=new Set(comparison.resolvedIds),ongoing=new Set(comparison.ongoingIds);
+ const group=(issue:NeededReport["issues"][number])=>JSON.stringify([issue.finding.code,issue.finding.skill,issue.finding.target,issue.location]);
+ const removed=new Map<string,Array<NeededReport["issues"][number]>>();
+ for(const issue of left)if(absent.has(issue.id)){const key=group(issue),items=removed.get(key)??[];items.push(issue);removed.set(key,items);}
+ const details=new Map<string,ComparisonDetail>();
+ const add=(code:string,change:string)=>{const key=JSON.stringify([code,change]);const row=details.get(key)??{code,change,count:0};row.count++;details.set(key,row);};
+ let changed=0;
+ for(const issue of right){
+  if(ongoing.has(issue.id))add(issue.finding.code,"ongoing");
+  else if(added.has(issue.id)){const paired=removed.get(group(issue))?.pop();if(paired){changed++;add(issue.finding.code,"changed");}else add(issue.finding.code,"added");}
+ }
+ for(const items of removed.values())for(const issue of items)add(issue.finding.code,"resolved");
+ const rows=[...details.values()].sort((a,b)=>a.code.localeCompare(b.code)||a.change.localeCompare(b.change));
+ return {status:"compared",counts:{added:comparison.newIds.length-changed,ongoing:comparison.ongoingIds.length,resolved:comparison.resolvedIds.length-changed,changed},details:rows.slice(0,32),detailsTotal:rows.length,detailsTruncated:rows.length>32};
+}
diff --git a/tests/workbench/page.test.ts b/tests/workbench/page.test.ts
index c7e8a91..a560857 100644
--- a/tests/workbench/page.test.ts
+++ b/tests/workbench/page.test.ts
@@ -53,12 +53,42 @@ async function page(failure?: "network" | "invalid-json" | "expired-session", de
       return {};
     }};
   };
-  runInNewContext(workbenchScript, {document: {getElementById: get, querySelector: () => get("meta"), querySelectorAll: () => [], createElement: () => new Element()}, fetch, URL, Blob, setTimeout});
+  runInNewContext(workbenchScript, {document: {getElementById: get, querySelector: () => get("meta"), querySelectorAll: () => [], createElement: () => new Element()}, fetch, URL, Blob, setTimeout, AbortController});
   await new Promise(resolve => setImmediate(resolve));
   return {get, offsets, actions,inputs,respond(action:string,value:unknown){responses.set(action,value);}, fail(action: string, message: string) { rejected.set(action, message); }, async finishInitialHistory() { releaseHistory(); await new Promise(resolve => setImmediate(resolve)); }, async click(id: string) { await get(id).onclick?.(); await new Promise(resolve => setImmediate(resolve)); }};
 }
 
 describe("workbench interactions", () => {
+  it("ignores delayed history replies after an input change",async()=>{
+    const ui=await page(),before="11111111-1111-4111-8111-111111111111",after="22222222-2222-4222-8222-222222222222";
+    ui.get("history-compare-before").value=before;ui.get("history-compare-after").value=after;
+    let release!:(value:unknown)=>void;ui.respond("history/compare",new Promise(resolve=>{release=resolve}));
+    const pending=ui.click("history-compare");await new Promise(resolve=>setImmediate(resolve));
+    ui.get("history-compare-after").value=before;ui.get("history-compare-after").events.get("input")?.();
+    release({schema:"skillsync.history-comparison/v1",kind:"skill",status:"compared",before:{id:before},after:{id:after},counts:{added:0,ongoing:0,resolved:0,changed:0},details:[],detailsTotal:0,detailsTruncated:false,readOnly:true,execution:"not-run",provenance:"not-authenticated"});
+    await pending;expect(ui.get("history-compare-result").hidden).toBe(true);expect(ui.get("history-compare-info").textContent).toBe("");
+  });
+
+  it("compares history independently of entered paths and reviewed apply consent", async () => {
+    const ui=await page();await ui.click("verify");await ui.click("plan");
+    ui.get("confirm").checked=true;ui.get("confirm").onchange?.();await ui.click("nav-history");
+    const before="11111111-1111-4111-8111-111111111111",after="22222222-2222-4222-8222-222222222222";
+    ui.get("history-compare-before").value=before;ui.get("history-compare-after").value=after;
+    ui.respond("history/compare",{schema:"skillsync.history-comparison/v1",kind:"skill",status:"compared",before:{id:before},after:{id:after},counts:{added:1,ongoing:2,resolved:3,changed:1},details:[{code:"test.code",change:"added",count:1},{code:"test.code",change:"ongoing",count:2},{code:"test.code",change:"resolved",count:3},{code:"test.code",change:"changed",count:1}],detailsTotal:4,detailsTruncated:false,readOnly:true,execution:"not-run",provenance:"not-authenticated"});
+    const initial=ui.actions.length;await ui.click("history-compare");
+    expect(ui.actions.slice(initial)).toEqual(["history/compare"]);
+    expect(ui.inputs.at(-1)?.input).toEqual({beforeId:before,afterId:after});
+    expect(ui.get("history-compare-info").textContent).toContain("历史");
+    expect(ui.get("root").value).toBe("/synthetic/review");expect(ui.get("confirm").checked).toBe(true);
+    await ui.click("nav-single");expect(ui.get("apply").disabled).toBe(false);
+  });
+
+  it("keeps unavailable history comparison distinct from zero changes", async () => {
+    const ui=await page();const before="11111111-1111-4111-8111-111111111111",after="22222222-2222-4222-8222-222222222222";
+    ui.get("history-compare-before").value=before;ui.get("history-compare-after").value=after;
+    ui.respond("history/compare",{schema:"skillsync.history-comparison/v1",kind:"skill",status:"unavailable",before:{id:before},after:{id:after},reason:"incomplete-evidence",readOnly:true,execution:"not-run",provenance:"not-authenticated"});
+    await ui.click("history-compare");expect(ui.get("history-compare-info").textContent).toContain("不完整");expect(ui.get("history-compare-result").children).toHaveLength(0);
+  });
   it("applies history filters explicitly, keeps them for paging and restores successful criteria on failure", async () => {
     const ui=await page();
     ui.get("history-query").value="review";ui.get("history-kind").value="verify";ui.get("history-exit").value="0";
diff --git a/tests/workbench/server.test.ts b/tests/workbench/server.test.ts
index 1849432..ca3be6d 100644
--- a/tests/workbench/server.test.ts
+++ b/tests/workbench/server.test.ts
@@ -22,6 +22,47 @@ async function setup(cliPath = resolve("dist/cli/index.js")) {
   return {base, root, script, app, api, token};
 }
 describe("real CLI graphical workbench", () => {
+  it("compares saved verification evidence without commands, history writes or consuming the current plan", async () => {
+    const {api,base,root,script}=await setup();
+    await api("select",{path:root,kind:"skill"});
+    const first=await api("verify"), planned=await api("plan");
+    const folder=join(base,"state"), info=await stat(folder), history=new WorkbenchHistory(folder,`${info.dev}:${info.ino}`);
+    const original=await history.read(first.data.historyId);
+    const after=JSON.parse(original.output!);
+    after.findings=after.findings.filter((row:{code:string})=>row.code!=="structure.invalid-script-mode");
+    after.issues=after.issues.filter((row:{finding:{code:string}})=>row.finding.code!=="structure.invalid-script-mode");
+    after.summary={total:after.findings.length,pass:0,warn:0,fail:0,unknown:0};
+    for(const row of after.findings)after.summary[row.status]++;
+    after.exitCode=0;
+    const later=await history.append({kind:"verify",selection:original.record.selection,exitCode:0},JSON.stringify(after));
+    const names=await readdir(folder), bytes=await Promise.all(names.map(name=>readFile(join(folder,name))));
+    const compared=await api("history/compare",{beforeId:first.data.historyId,afterId:later.id});
+    expect(compared.status).toBe(200);expect(compared.data.status).toBe("compared");
+    expect(compared.data.counts.resolved).toBe(1);expect(compared.data.readOnly).toBe(true);
+    expect(compared.data.execution).toBe("not-run");expect(JSON.stringify(compared.data)).not.toContain(base);
+    expect(await readdir(folder)).toEqual(names);
+    for(let i=0;i<names.length;i++)expect(await readFile(join(folder,names[i]))).toEqual(bytes[i]);
+    expect((await stat(script)).mode&0o777).toBe(0o777);
+    expect((await api("apply",{id:planned.data.id,confirm:true})).status).toBe(200);
+  });
+
+  it("never compares different selections, incomplete evidence or mutated bodies as empty successes", async () => {
+    const {api,base,root}=await setup();await api("select",{path:root,kind:"skill"});
+    const first=await api("verify"), folder=join(base,"state"), info=await stat(folder), history=new WorkbenchHistory(folder,`${info.dev}:${info.ino}`);
+    const saved=await history.read(first.data.historyId), report=JSON.parse(saved.output!);
+    const foreign=await history.append({kind:"verify",selection:{...saved.record.selection,identity:"9:9"},exitCode:0},"PRIVATE_INVALID_BODY");
+    const different=await api("history/compare",{beforeId:first.data.historyId,afterId:foreign.id});
+    expect(different.status).toBe(200);expect(different.data.reason).toBe("selection-changed");expect(different.data.counts).toBeUndefined();
+    report.exitCode=2;
+    const incomplete=await history.append({kind:"verify",selection:saved.record.selection,exitCode:2},JSON.stringify(report));
+    const missing=await api("history/compare",{beforeId:first.data.historyId,afterId:incomplete.id});
+    expect(missing.data.status).toBe("unavailable");expect(missing.data.counts).toBeUndefined();
+    expect((await api("history/compare",{beforeId:"../private",afterId:incomplete.id})).status).toBe(400);
+    expect((await api("history/compare",{beforeId:first.data.historyId,afterId:first.data.historyId})).status).toBe(400);
+    await writeFile(join(folder,saved.record.dataFile!),"PRIVATE_TAMPERED_BODY");
+    const tampered=await api("history/compare",{beforeId:first.data.historyId,afterId:incomplete.id});
+    expect(tampered.status).toBe(400);expect(JSON.stringify(tampered.data)).not.toContain("PRIVATE_TAMPERED_BODY");
+  });
   it("filters history metadata before paging without opening bodies or leaking parent paths", async () => {
     const {api, base} = await setup();
     const folder = join(base, "state"), info = await stat(folder);
diff --git a/tests/workbench/verification-comparison.test.ts b/tests/workbench/verification-comparison.test.ts
new file mode 100644
index 0000000..cc2f570
--- /dev/null
+++ b/tests/workbench/verification-comparison.test.ts
@@ -0,0 +1,54 @@
+import {describe,it,expect} from "vitest";
+import {mkdtemp,stat,realpath} from "node:fs/promises";
+import {tmpdir} from "node:os";
+import {join} from "node:path";
+import {toIssue} from "../../src/domain/issue.js";
+import type {Finding} from "../../src/domain/result.js";
+import {artifactSetHash} from "../../src/domain/artifact-report.js";
+import {WorkbenchHistory} from "../../src/workbench/history.js";
+import {parseComparisonReport,compareVerificationReports} from "../../src/workbench/verification-comparison.js";
+
+function finding(code:string,evidence="old",status:Finding["status"]="warn"):Finding{return {level:0,severity:"warn",status,code,skill:"fixture",message:"PRIVATE_FINDING_MESSAGE",evidence:[{evidence}]};}
+function report(findings:Finding[]){
+ const summary={total:findings.length,pass:0,warn:0,fail:0,unknown:0};for(const row of findings)summary[row.status]++;
+ return {schema_version:1,generated_at:"2026-11-06T00:00:00.000Z",targets:[{name:"verify-1",path:"[local path]",scope:"explicit"}],findings,issues:findings.map(row=>toIssue(row,{})),summary,exitCode:0};
+}
+describe("saved verification comparison boundaries",()=>{
+ it("pairs evidence changes without calling an absent warning a verified fix",()=>{
+  const before=parseComparisonReport(report([finding("test.changed"),finding("test.absent"),finding("test.ongoing")]));
+  const after=parseComparisonReport(report([finding("test.changed","new"),finding("test.added"),finding("test.ongoing")]));
+  const result=compareVerificationReports(before,after);expect(result.status).toBe("compared");
+  if(result.status!=="compared")throw new Error("comparison unavailable");
+  expect(result.counts).toEqual({added:1,ongoing:1,resolved:1,changed:1});
+  expect(JSON.stringify(result)).not.toContain("PRIVATE_FINDING_MESSAGE");expect(result.details).toHaveLength(4);
+ });
+ it("rejects duplicate identifiers, missing findings and inconsistent summaries",()=>{
+  const value=report([finding("test.first"),finding("test.second")]);
+  value.issues[1].id=value.issues[0].id;expect(()=>parseComparisonReport(value)).toThrow();
+  value.issues.pop();expect(()=>parseComparisonReport(value)).toThrow();
+  const wrong=report([finding("test.first")]);wrong.summary.total=0;expect(()=>parseComparisonReport(wrong)).toThrow();
+  expect(()=>parseComparisonReport({...wrong,issues:Array(10000).fill({})})).toThrow();
+ });
+ it("distinguishes saturated or unknown evidence from zero changes and caps code rows",()=>{
+  const empty=parseComparisonReport(report([]));
+  const saturated=parseComparisonReport(report(Array.from({length:256},(_,i)=>finding("test.code"+i))));
+  expect(compareVerificationReports(saturated,empty).status).toBe("unavailable");
+  expect(compareVerificationReports(parseComparisonReport(report([finding("test.unknown","x","unknown")])),empty).status).toBe("unavailable");
+  const detail=compareVerificationReports(parseComparisonReport(report(Array.from({length:40},(_,i)=>finding("test.code"+i)))),empty);
+  if(detail.status!=="compared")throw new Error("comparison unavailable");
+  expect(detail.counts.resolved).toBe(40);expect(detail.details).toHaveLength(32);expect(detail.detailsTotal).toBe(40);expect(detail.detailsTruncated).toBe(true);
+ });
+ it("compares offline artifact history through the existing contract-bound parser",async()=>{
+  const root=await realpath(await mkdtemp(join(tmpdir(),"sync-saved-artifact-"))),info=await stat(root),history=new WorkbenchHistory(root,`${info.dev}:${info.ino}`);
+  const selection={path:"/synthetic/offline-artifacts",identity:"1:2",kind:"artifacts" as const,contract:"/synthetic/missing-contract.json",delivery:false};
+  const files=[{path:"table.csv",bytes:10,sha256:"b".repeat(64)}];
+  const before={schema:"skillsync.artifacts-report/v1",status:"passed",exitCode:0,evidence:"physical-files",execution:"not-run",provenance:"not-authenticated",receipt_binding:"not-provided",contract_sha256:"a".repeat(64),artifact_set_sha256:artifactSetHash(files),files,findings:[]};
+  const after={...before,status:"failed",exitCode:1,findings:[{code:"csv.value-mismatch",path:"table.csv",field:"amount",message:"PRIVATE_CELL_SENTINEL"}]};
+  const left=await history.append({kind:"verify",selection,exitCode:0},JSON.stringify(before)),right=await history.append({kind:"verify",selection,exitCode:1},JSON.stringify(after));
+  const compared=await history.compare(left.id,right.id);expect(compared.status).toBe("compared");
+  if(!("counts" in compared))throw new Error("counts unavailable");
+  expect(compared.counts.added).toBe(1);expect(JSON.stringify(compared)).not.toContain("PRIVATE_CELL_SENTINEL");expect(JSON.stringify(compared)).not.toContain(selection.path);
+  const changed=await history.append({kind:"verify",selection,exitCode:1},JSON.stringify({...after,contract_sha256:"c".repeat(64)}));
+  const unavailable=await history.compare(left.id,changed.id);expect(unavailable.status).toBe("unavailable");expect(unavailable).not.toHaveProperty("counts");
+ });
+});