diff --git a/ui-opentui/src/logic/env.ts b/ui-opentui/src/logic/env.ts
index 8b19607e540..6c86a8ca9b9 100644
--- a/ui-opentui/src/logic/env.ts
+++ b/ui-opentui/src/logic/env.ts
@@ -15,28 +15,29 @@ export function envFlag(value: string | undefined, fallback: boolean): boolean {
   return fallback
 }
 
-/** Default cap on output lines shown by an EXPANDED tool body. */
-export const TOOL_OUTPUT_LINES_DEFAULT = 200
-
 /**
  * Parse `HERMES_TUI_TOOL_OUTPUT_LINES` (a TUI-only env var — deliberately NOT
  * a config.yaml knob): how many output lines an expanded tool body shows.
- * Unset/garbage → 200 (the long-standing default); a positive integer → that
- * cap; `0` → Infinity (UNLIMITED — show the entire output).
+ * UNSET → Infinity (UNLIMITED — expanded tool output is uncapped by default;
+ * setting the var is how you RESTORE a cap, e.g. `=200`). A positive integer
+ * → that cap. `0` → Infinity too (back-compat: it was the old opt-in
+ * "unlimited" value). Garbage → Infinity (unrecognized ≙ no cap asked for —
+ * the semantic is "cap only when the user asked for one").
  */
 export function envOutputLines(value: string | undefined): number {
   const v = value?.trim() ?? ''
-  if (!/^\d+$/.test(v)) return TOOL_OUTPUT_LINES_DEFAULT
+  if (!/^\d+$/.test(v)) return Number.POSITIVE_INFINITY
   const n = Number.parseInt(v, 10)
   return n === 0 ? Number.POSITIVE_INFINITY : n
 }
 
 /**
- * Whether `HERMES_TUI_TOOL_OUTPUT_LINES` was EXPLICITLY set (any non-empty
- * value, even an unparseable one). When it is, the store prefers the
- * always-full raw `result` over a gateway tail-capped `result_text` — see
- * store.ts tool.complete.
+ * Whether NO line cap applies (unset / `0` / unparseable). When unlimited,
+ * the store prefers the always-full raw `result` over a gateway tail-capped
+ * `result_text` — an "unlimited" view of a tail would still be missing its
+ * head — see store.ts tool.complete. With an explicit finite cap the gateway
+ * tail (+ honest omitted note) is kept: the user asked for a bounded view.
  */
-export function envOutputLinesSet(value: string | undefined): boolean {
-  return (value?.trim() ?? '') !== ''
+export function envOutputUnlimited(value: string | undefined): boolean {
+  return envOutputLines(value) === Number.POSITIVE_INFINITY
 }
diff --git a/ui-opentui/src/logic/store.ts b/ui-opentui/src/logic/store.ts
index 5d031abd696..77dcfec6202 100644
--- a/ui-opentui/src/logic/store.ts
+++ b/ui-opentui/src/logic/store.ts
@@ -23,7 +23,7 @@ import {
 } from '../boundary/schema/SessionInfo.ts'
 import type { DetailsMode } from './details.ts'
 import { diffStats, type DiffStats } from './diff.ts'
-import { envOutputLinesSet } from './env.ts'
+import { envOutputUnlimited } from './env.ts'
 import { stripAnsi, stripOmittedNote, stripToolEnvelope } from './toolOutput.ts'
 import { DEFAULT_THEME, type Theme, themeFromSkin } from './theme.ts'
 
@@ -744,17 +744,18 @@ export function createSessionStore() {
         let { body: rawBody, omittedNote } = stripOmittedNote(
           readStr(event.payload, 'result_text') ?? stringifyResult(event.payload['result']) ?? summary ?? ''
         )
-        // HERMES_TUI_TOOL_OUTPUT_LINES set → the user explicitly controls how much
-        // output the expanded view shows, but a gateway-capped `result_text`
-        // (omittedNote) is only a TAIL — substituting the always-full raw `result`
-        // is the only way flag=0 (unlimited) can actually show everything. Same
-        // display pipeline (envelope strip) — and the same raw-result redaction
-        // tradeoff — as the existing non-verbose stringifyResult fallback above.
-        // The omitted note no longer applies to the full body; "+N more lines"
-        // (view-side) stays honest for caps below the full length. File-edit JSON
+        // The view cap is UNLIMITED (HERMES_TUI_TOOL_OUTPUT_LINES unset/0 — the
+        // default), but a gateway-capped `result_text` (omittedNote) is only a
+        // TAIL — substituting the always-full raw `result` is the only way the
+        // uncapped view can actually show everything. Same display pipeline
+        // (envelope strip) — and the same raw-result redaction tradeoff — as the
+        // existing non-verbose stringifyResult fallback above. The omitted note
+        // no longer applies to the full body. With an explicit FINITE cap the
+        // gateway tail + note are kept (the user asked for a bounded view; the
+        // view-side "+N more lines" stays honest below that). File-edit JSON
         // results stay parseable, so fileTool's diffOutputPlan still suppresses
         // the diff echo. The redacted-argsText precedence is untouched.
-        if (omittedNote && envOutputLinesSet(process.env.HERMES_TUI_TOOL_OUTPUT_LINES)) {
+        if (omittedNote && envOutputUnlimited(process.env.HERMES_TUI_TOOL_OUTPUT_LINES)) {
           const full = stringifyResult(event.payload['result'])
           if (full !== undefined) {
             rawBody = full
diff --git a/ui-opentui/src/test/env.test.ts b/ui-opentui/src/test/env.test.ts
index 1d92fb386d7..4ecb5c65ad2 100644
--- a/ui-opentui/src/test/env.test.ts
+++ b/ui-opentui/src/test/env.test.ts
@@ -1,6 +1,6 @@
 import { describe, expect, test } from 'vitest'
 
-import { envFlag, envOutputLines, envOutputLinesSet, TOOL_OUTPUT_LINES_DEFAULT } from '../logic/env.ts'
+import { envFlag, envOutputLines, envOutputUnlimited } from '../logic/env.ts'
 
 describe('envFlag', () => {
   test('recognizes truthy values regardless of case/whitespace', () => {
@@ -31,37 +31,38 @@ describe('envFlag', () => {
 })
 
 describe('envOutputLines (HERMES_TUI_TOOL_OUTPUT_LINES)', () => {
-  test('unset → the 200-line default (today’s behavior)', () => {
-    expect(TOOL_OUTPUT_LINES_DEFAULT).toBe(200)
-    expect(envOutputLines(undefined)).toBe(200)
-    expect(envOutputLines('')).toBe(200)
-    expect(envOutputLines('   ')).toBe(200)
+  test('unset → Infinity (UNLIMITED by default — the env var RESTORES a cap)', () => {
+    expect(envOutputLines(undefined)).toBe(Number.POSITIVE_INFINITY)
+    expect(envOutputLines('')).toBe(Number.POSITIVE_INFINITY)
+    expect(envOutputLines('   ')).toBe(Number.POSITIVE_INFINITY)
   })
 
   test('a positive integer → that cap (whitespace-tolerant)', () => {
     expect(envOutputLines('50')).toBe(50)
     expect(envOutputLines(' 50 ')).toBe(50)
     expect(envOutputLines('1')).toBe(1)
+    expect(envOutputLines('200')).toBe(200)
     expect(envOutputLines('1000')).toBe(1000)
   })
 
-  test('"0" → Infinity (UNLIMITED — show the entire output)', () => {
+  test('"0" → Infinity too (back-compat with the old opt-in "unlimited" value)', () => {
     expect(envOutputLines('0')).toBe(Number.POSITIVE_INFINITY)
   })
 
-  test('garbage → the 200-line default', () => {
-    expect(envOutputLines('unlimited')).toBe(200)
-    expect(envOutputLines('-5')).toBe(200)
-    expect(envOutputLines('1.5')).toBe(200)
-    expect(envOutputLines('50 lines')).toBe(200)
+  test('garbage → Infinity (unrecognized ≙ no cap asked for)', () => {
+    expect(envOutputLines('unlimited')).toBe(Number.POSITIVE_INFINITY)
+    expect(envOutputLines('-5')).toBe(Number.POSITIVE_INFINITY)
+    expect(envOutputLines('1.5')).toBe(Number.POSITIVE_INFINITY)
+    expect(envOutputLines('50 lines')).toBe(Number.POSITIVE_INFINITY)
   })
 
-  test('envOutputLinesSet: set means any non-empty value, even garbage', () => {
-    expect(envOutputLinesSet(undefined)).toBe(false)
-    expect(envOutputLinesSet('')).toBe(false)
-    expect(envOutputLinesSet('   ')).toBe(false)
-    expect(envOutputLinesSet('0')).toBe(true)
-    expect(envOutputLinesSet('50')).toBe(true)
-    expect(envOutputLinesSet('garbage')).toBe(true)
+  test('envOutputUnlimited: true unless an explicit finite cap was asked for', () => {
+    expect(envOutputUnlimited(undefined)).toBe(true)
+    expect(envOutputUnlimited('')).toBe(true)
+    expect(envOutputUnlimited('   ')).toBe(true)
+    expect(envOutputUnlimited('0')).toBe(true)
+    expect(envOutputUnlimited('garbage')).toBe(true)
+    expect(envOutputUnlimited('50')).toBe(false)
+    expect(envOutputUnlimited('200')).toBe(false)
   })
 })
diff --git a/ui-opentui/src/test/tools.test.tsx b/ui-opentui/src/test/tools.test.tsx
index 7526cb5d2e1..6ea7a9a8260 100644
--- a/ui-opentui/src/test/tools.test.tsx
+++ b/ui-opentui/src/test/tools.test.tsx
@@ -4,7 +4,8 @@
  * acceptance gate asserts NO raw JSON syntax (`{"` / `":`) ever reaches the
  * frame for tool parts, collapsed or expanded — delegate_task carries the
  * Ink-parity "(/agents to monitor)" hint, and the bash renderer shows the
- * command verbatim collapsed + the full (EXPANDED_MAX-capped) output expanded.
+ * command verbatim collapsed + the FULL output expanded (uncapped by default;
+ * HERMES_TUI_TOOL_OUTPUT_LINES restores a cap).
  * Expansion goes through the REAL mouse path: mockMouse clicks the header row
  * (found by scanning the frame). The long-output cap is asserted at the Body
  * level (a tall frame would otherwise hide the trailing note).
@@ -180,7 +181,10 @@ describe('bash tool renderer — command + full output (Epic 2.4)', () => {
     }
   })
 
-  test('long output is capped to EXPANDED_MAX with an honest "+N more lines" note', async () => {
+  test('long output with an explicit =200 cap restored gets the honest "+N more lines" note', async () => {
+    // Output is UNCAPPED by default now — restore the old 200-line cap explicitly.
+    const prev = process.env.HERMES_TUI_TOOL_OUTPUT_LINES
+    process.env.HERMES_TUI_TOOL_OUTPUT_LINES = '200'
     const lines = Array.from({ length: 250 }, (_, i) => `line-${String(i + 1).padStart(3, '0')}`)
     const part: ToolPartState = {
       type: 'tool',
@@ -203,11 +207,13 @@ describe('bash tool renderer — command + full output (Epic 2.4)', () => {
       const frame = await probe.waitForFrame(f => f.includes('+50 more lines'))
       expect(frame).toContain('$ for i in range(250): print(i)')
       expect(frame).toContain('line-001') // the cap keeps the HEAD of the output
-      expect(frame).toContain('line-200') // …up to EXPANDED_MAX
+      expect(frame).toContain('line-200') // …up to the restored cap
       expect(frame).not.toContain('line-201') // the rest is honestly elided
       expect(frame).toContain('… +50 more lines')
     } finally {
       probe.destroy()
+      if (prev === undefined) delete process.env.HERMES_TUI_TOOL_OUTPUT_LINES
+      else process.env.HERMES_TUI_TOOL_OUTPUT_LINES = prev
     }
   })
 
@@ -620,7 +626,7 @@ describe('HERMES_TUI_TOOL_OUTPUT_LINES — expanded-output line cap (TUI-only en
     })
   })
 
-  test('flag unset: the same 250-line output still caps at 200 + the honest note (default unchanged)', async () => {
+  test('flag unset: the same 250-line output renders ALL lines (UNLIMITED is the default now)', async () => {
     await withFlag(undefined, async () => {
       const lines = Array.from({ length: 250 }, (_, i) => `row-${String(i + 1).padStart(3, '0')}`)
       const part: ToolPartState = {
@@ -640,17 +646,48 @@ describe('HERMES_TUI_TOOL_OUTPUT_LINES — expanded-output line cap (TUI-only en
         { width: 80, height: 260 }
       )
       try {
-        const frame = await probe.waitForFrame(f => f.includes('+50 more lines'))
-        expect(frame).toContain('row-200')
-        expect(frame).not.toContain('row-201')
-        expect(frame).toContain('… +50 more lines')
+        const frame = await probe.waitForFrame(f => f.includes('row-250'))
+        expect(frame).toContain('row-001')
+        expect(frame).toContain('row-201') // beyond the old 200-line default…
+        expect(frame).toContain('row-250') // …down to the very last line
+        expect(frame).not.toContain('more lines') // and no truncation note
       } finally {
         probe.destroy()
       }
     })
   })
 
-  test('store: flag set + gateway tail-cap (omittedNote) + full raw result → body derived from the raw result', async () => {
+  test('flag=50: an explicit cap is RESTORED — 50 lines + the honest "+200 more lines" note', async () => {
+    await withFlag('50', async () => {
+      const lines = Array.from({ length: 250 }, (_, i) => `row-${String(i + 1).padStart(3, '0')}`)
+      const part: ToolPartState = {
+        type: 'tool',
+        id: 'u3',
+        name: 'terminal',
+        state: 'complete',
+        args: { command: 'seq 1 250' },
+        resultText: lines.join('\n')
+      }
+      const probe = await renderProbe(
+        () => (
+          <ThemeProvider>
+            <BashToolBody part={part} width={70} />
+          </ThemeProvider>
+        ),
+        { width: 80, height: 260 }
+      )
+      try {
+        const frame = await probe.waitForFrame(f => f.includes('+200 more lines'))
+        expect(frame).toContain('row-050')
+        expect(frame).not.toContain('row-051')
+        expect(frame).toContain('… +200 more lines')
+      } finally {
+        probe.destroy()
+      }
+    })
+  })
+
+  test('store: unlimited cap + gateway tail-cap (omittedNote) + full raw result → body derived from the raw result', async () => {
     const full = Array.from({ length: 250 }, (_, i) => `full-${i + 1}`).join('\n')
     const cappedTail = ['full-241', 'full-242', 'full-243'].join('\n') // what the gateway kept
     const payload = {
@@ -675,8 +712,19 @@ describe('HERMES_TUI_TOOL_OUTPUT_LINES — expanded-output line cap (TUI-only en
       expect(part?.omittedNote).toBeUndefined() // the note no longer applies
     })
 
-    // flag UNSET → today's behavior: the gateway tail + the tidy omitted note
+    // flag UNSET → unlimited is the DEFAULT now: the full raw result wins too
     await withFlag(undefined, () => {
+      const store = createSessionStore()
+      seedTool(store, { tool_id: 'p1', name: 'terminal' }, payload)
+      const part = partOf(store)
+      expect(part?.resultText).toContain('full-1\n')
+      expect(part?.resultText).toContain('full-250')
+      expect(part?.omittedNote).toBeUndefined()
+    })
+
+    // an explicit FINITE cap (=50) → the user asked for a bounded view: keep
+    // the gateway tail + the honest omitted note (the view caps further)
+    await withFlag('50', () => {
       const store = createSessionStore()
       seedTool(store, { tool_id: 'p1', name: 'terminal' }, payload)
       const part = partOf(store)
@@ -685,7 +733,7 @@ describe('HERMES_TUI_TOOL_OUTPUT_LINES — expanded-output line cap (TUI-only en
       expect(part?.omittedNote).toBe('240 lines / 2000 chars')
     })
 
-    // flag set but NO raw result on the wire → keep the tail + note (no crash)
+    // unlimited but NO raw result on the wire → keep the tail + note (no crash)
     await withFlag('0', () => {
       const store = createSessionStore()
       const withoutRaw: Record<string, unknown> = { ...payload }
diff --git a/ui-opentui/src/view/tools/bashTool.tsx b/ui-opentui/src/view/tools/bashTool.tsx
index 45cd5ec95cf..33733c850fb 100644
--- a/ui-opentui/src/view/tools/bashTool.tsx
+++ b/ui-opentui/src/view/tools/bashTool.tsx
@@ -2,9 +2,9 @@
  * BashTool — renderer for the shell-ish tools `terminal`, `execute_code` and
  * `process` (Epic 2.4). Collapsed: the COMMAND BEING INVOKED, verbatim, on one
  * line (the shell truncates to width; expanding reveals the rest). Expanded:
- * the full command (`$ `-prefixed, multi-line safe) and the FULL output, kept
- * to the expanded-lines cap (HERMES_TUI_TOOL_OUTPUT_LINES; default 200, 0 →
- * unlimited) with the honest omitted / "+N more lines" notes from
+ * the full command (`$ `-prefixed, multi-line safe) and the FULL output —
+ * uncapped by default (HERMES_TUI_TOOL_OUTPUT_LINES restores a cap, e.g.
+ * `=200`) with the honest omitted / "+N more lines" notes from
  * `logic/toolOutput.ts` (via the shared ToolOutputBlock).
  *
  * Arg keys verified against the Python tool schemas:
diff --git a/ui-opentui/src/view/tools/defaultTool.tsx b/ui-opentui/src/view/tools/defaultTool.tsx
index 480e3bcb1a2..7ef655e89c4 100644
--- a/ui-opentui/src/view/tools/defaultTool.tsx
+++ b/ui-opentui/src/view/tools/defaultTool.tsx
@@ -8,9 +8,9 @@
  *     `(N fields)` / `(N items)` (opencode's primitive-only `input()` idea)
  * A single field whose value already equals the header's primary-arg preview is
  * hidden (it adds nothing over the header). The output body keeps the store's
- * envelope-stripped text, capped to the expanded-lines cap (the
- * HERMES_TUI_TOOL_OUTPUT_LINES env var; default 200, 0 → unlimited) with the
- * honest omitted / "+N more lines" notes. `ToolOutputBlock` is shared with the
+ * envelope-stripped text, UNCAPPED by default (the HERMES_TUI_TOOL_OUTPUT_LINES
+ * env var restores a cap, e.g. `=200`) with the honest omitted / "+N more
+ * lines" notes when a cap applies. `ToolOutputBlock` is shared with the
  * per-tool renderers (bash, …). Fully themed; labels/notes are chrome
  * (selectable=false).
  */
@@ -24,11 +24,13 @@ import type { ToolBodyProps, ToolRenderer } from './registry.tsx'
 
 /**
  * Max output lines shown when expanded — `HERMES_TUI_TOOL_OUTPUT_LINES` (a
- * TUI-only env var, not a config.yaml knob): unset/garbage → 200 (a sane cap
- * to avoid huge renders), positive int → that cap, `0` → Infinity (unlimited).
- * Memory note: this is safe to lift — tool rows mount collapsed (no body), and
- * the rolling HERMES_TUI_MAX_MESSAGES cap bounds the transcript's Yoga-node
- * high-water mark; an expanded body's nodes free on collapse/unmount.
+ * TUI-only env var, not a config.yaml knob): unset/garbage/`0` → Infinity
+ * (UNLIMITED, the default — all tool output is viewable), positive int →
+ * restore that cap.
+ * Memory note: unlimited-by-default is safe — tool rows mount collapsed (no
+ * body), bodies only exist while EXPANDED, and the rolling
+ * HERMES_TUI_MAX_MESSAGES cap bounds the transcript's Yoga-node high-water
+ * mark; an expanded body's nodes free on collapse/unmount.
  */
 export function expandedMaxLines(): number {
   return envOutputLines(process.env.HERMES_TUI_TOOL_OUTPUT_LINES)