fix(ui-web): say on the sheet when the engine shortened the evidence

Review found the half of the cap that was missing. The gate clips an oversized
account of a call down to what a person reads and sets `truncated`, but the
sheet rendered the clipped diff, input and arguments without ever reading that
flag. The reader saw a change that looked whole, and answered about the part
they could see.

Every layout now carries the line, below the evidence, where the reader has
just run out of it -- and in amber rather than the faint grey of "there was
nothing to show", because this says the opposite: there is more than this.

Run against the code with the line removed: the new case fails on the first
layout it checks.

Co-authored-by: Claude (claude-opus-5) <noreply@anthropic.com>

Author: gloryfromca

i18n/messages.json

@@ -5555,6 +5555,10 @@
       "en": "No preview of the change",
       "zh": "无法预览改动"
     },
+    "gui.confirm.ev.cut": {
+      "en": "shortened to what fits -- the rest is not shown",
+      "zh": "内容过长，这里只显示了前一部分"
+    },
     "gui.confirm.land.once": {
       "en": "Allowed, just this once",
       "zh": "已允许 · 只这一次"

ui-tui/src/i18n/messages.generated.ts

@@ -1588,6 +1588,7 @@ export const UI_TEXT: Record<Locale, Record<string, string>> = {
     'gui.confirm.why.unknown': '{who} wants to do this; you have not allowed it yet.',
     'gui.confirm.ev.created': 'new file',
     'gui.confirm.ev.nodiff': 'No preview of the change',
+    'gui.confirm.ev.cut': 'shortened to what fits -- the rest is not shown',
     'gui.confirm.land.once': 'Allowed, just this once',
     'gui.confirm.land.always': "Won't ask again for: {pattern}, in every working directory",
     'gui.confirm.land.revoke': 'Undo',
@@ -3453,6 +3454,7 @@ export const UI_TEXT: Record<Locale, Record<string, string>> = {
     'gui.confirm.why.unknown': '{who} 要执行这个操作，你还没授权过。',
     'gui.confirm.ev.created': '新建文件',
     'gui.confirm.ev.nodiff': '无法预览改动',
+    'gui.confirm.ev.cut': '内容过长，这里只显示了前一部分',
     'gui.confirm.land.once': '已允许 · 只这一次',
     'gui.confirm.land.always': '以后不再问：{pattern}，在所有工作目录生效',
     'gui.confirm.land.revoke': '收回',

ui-web/src/features/composer/GateSheet.tsx

@@ -28,6 +28,7 @@ export interface GateWords {
   readonly deny: string
   readonly created: string
   readonly nodiff: string
+  readonly cut: string
 }
 
 export interface GateProps {
@@ -50,6 +51,12 @@ const diffClass = (line: string): string =>
 function EvidenceBlock(
   { kind, evidence, command, words }: { kind: string; evidence: Evidence; command: string; words: GateWords },
 ): JSX.Element {
+  /* The gate cuts an oversized account down to what a person reads and says so
+     here. Answering about a change you can only see part of is the one thing
+     the cap must not cause, so the sheet says it was shortened wherever the
+     flag is set -- and says it below the evidence, where the reader has just
+     run out of it. */
+  const cut = evidence.truncated === true ? <div className="cp-ev-cut">{words.cut}</div> : null
   if (kind === 'file.write') {
     /* The file header names the path the line above already shows, and a
        two-line change should not spend its room on it. */
@@ -64,6 +71,7 @@ function EvidenceBlock(
             </pre>
           )
           : <div className="cp-ev-none">{words.nodiff}</div>}
+        {cut}
       </div>
     )
   }
@@ -72,11 +80,19 @@ function EvidenceBlock(
       <div className="what cp-ev">
         <div className="cp-ev-path">{str(evidence.server)}.{str(evidence.tool)}</div>
         <pre className="cp-json">{JSON.stringify(evidence.input ?? {}, null, 2)}</pre>
+        {cut}
       </div>
     )
   }
-  if (kind === 'shell.exec') return <div className="what">{str(evidence.command) || command}</div>
-  return <pre className="what cp-json">{JSON.stringify(evidence.input ?? evidence, null, 2)}</pre>
+  if (kind === 'shell.exec') {
+    return <div className="what">{str(evidence.command) || command}{cut}</div>
+  }
+  return (
+    <div className="what cp-ev">
+      <pre className="cp-json">{JSON.stringify(evidence.input ?? evidence, null, 2)}</pre>
+      {cut}
+    </div>
+  )
 }
 
 export function GateSheet({ kind, evidence, command, words, opts, onDeny }: GateProps): JSX.Element {

ui-web/src/features/composer/approve.test.ts

@@ -441,6 +441,26 @@ describe('the permission approval sheet', () => {
     }
   })
 
+  /* The gate cuts an oversized account down to what a person reads
+     (PermissionGate._clamped) and marks it. Rendering the clipped value without
+     the mark is the one thing the cap must not cause: the reader would answer
+     about a change they can only see part of, with nothing saying so. */
+  it('says so in every layout when the engine shortened the evidence', () => {
+    const cases = [
+      { kind: 'file.write', evidence: { path: '/w/big.py', created: false, diff: '-a\n+b', truncated: true } },
+      { kind: 'mcp.call', evidence: { server: 's', tool: 't', input: 'x'.repeat(40), truncated: true } },
+      { kind: 'shell.exec', evidence: { command: 'rm -rf x', cwd: '/w', truncated: true } },
+      { kind: 'unknown', evidence: { input: 'y'.repeat(40), truncated: true } },
+    ]
+    for (const c of cases) {
+      openApproval(fresh({ ...base, ...c, family: '' }), handlers())
+      expect(document.querySelector('.cp-ev-cut')?.textContent, c.kind).toBe('gui.confirm.ev.cut')
+    }
+    /* And stays quiet when nothing was cut. */
+    openApproval(fresh({ ...base, kind: 'file.write', family: '', evidence: { path: '/w/a.py', diff: '-a\n+b' } }), handlers())
+    expect(document.querySelector('.cp-ev-cut')).toBeNull()
+  })
+
   it('lays out a write as its path and diff, an MCP call as its tool and input, the rest as arguments', () => {
     const diff = '--- a\n+++ b\n@@ -1 +1 @@\n-x = 1\n+x = 2'
     openApproval(fresh({ ...base, kind: 'file.write', family: '', evidence: { path: '/w/a.py', created: false, diff } }), handlers())

ui-web/src/features/composer/approve.ts

@@ -231,6 +231,7 @@ function wordsFor(req: ApprovalReq): GateWords {
     deny: t('gui.confirm.deny'),
     created: t('gui.confirm.ev.created'),
     nodiff: t('gui.confirm.ev.nodiff'),
+    cut: t('gui.confirm.ev.cut'),
   }
 }
 

ui-web/src/features/composer/styles.css

@@ -66,6 +66,9 @@
 .cp-ev { display: grid; gap: 6px; }
 .cp-ev-path { font-weight: 600; }
 .cp-ev-none { color: var(--faint); font-style: italic; }
+/* Not faint like `.cp-ev-none`: that says there was nothing to show, this says
+   there is more than is shown, and the reader is about to answer about it. */
+.cp-ev-cut { color: var(--amber); font-size: 12px; }
 .cp-diff, .cp-json { margin: 0; font: inherit; white-space: pre-wrap; overflow-wrap: anywhere; }
 .cp-add { color: var(--moss); }
 .cp-del { color: var(--clay); }