Compare commits

..
Author SHA1 Message Date
taodengandClaude Fable 5 4239744c86 docs(readme): review nit — 'pre-v3.22' → 'pre-flag' (next version not fixed yet)
Reviewer nit from the Iron Rule 10 independent review of PR #156.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VqgWJcjxrjjL9L9SkpZyXR
2026-07-13 15:15:01 +10:00
taodengandClaude Fable 5 e95a7bb0f2 feat(tui): pin spawn effort via OCP_TUI_EFFORT (default low)
buildTuiCmd never passed --effort, so the pane's claude inherited a
HOME-dependent effortLevel: real-home mode inherits the operator's
~/.claude/settings.json (high/xhigh on typical operator hosts),
env-token scratch mode inherits claude's built-in default — proxied-turn
latency silently depended on which HOME mode resolveTuiHome() picked and
on an unrelated operator setting.

Pass --effort explicitly, from new env var OCP_TUI_EFFORT (default
"low"; allowlist low|medium|high|xhigh|max per `claude --help` 2.1.207;
"inherit" restores the pre-flag argv byte-for-byte; an invalid value
warns and falls back to "low" so a typo can never reach the pane argv).

Not endpoint-touching: no server.mjs change, no wire-level change — the
flag rides the existing interactive spawn (ADR 0007). Billing-pool
safety verified per the docs/plans/2026-07-13-tui-latency banner
protocol: startup banner stays "Claude Max" with "low effort".

Measured through a test OCP instance (:3979, TUI mode, real-home,
claude-sonnet-4-6, n=5+5, same ~1850-token prompt as floor.sh):

  before: median 11.30s  range 9.05-12.38s (spread 3.32s)  banner: high effort - Claude Max
  after:  median  9.55s  range 9.27-9.77s  (spread 0.50s)  banner: low effort - Claude Max
  OCP_TUI_EFFORT=inherit: banner back to "high effort" (pre-flag behavior restored)

README: new row in the Environment Variables table (release_kit
new_feature_doc_expectations: new env var -> README table). Tests: 4 new
buildTuiCmd cases (default, explicit level, inherit, invalid fallback);
suite 267 passed / 0 failed.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VqgWJcjxrjjL9L9SkpZyXR
2026-07-13 15:08:50 +10:00
5 changed files with 4 additions and 347 deletions
+1 -30
View File
@@ -1033,7 +1033,7 @@ Then restart OCP. At boot you will see (with the env token set, isolated home au
### What changes / what doesn't
- **Callers see no API change.** The response is a normal OpenAI completion object or chunked SSE — identical wire format.
- **No real token streaming *today* — but it is achievable, and planned.** TUI-mode currently buffers the full response then replays it as chunked SSE: you see a delay, then the complete response. This is a limitation of the current implementation, **not** of the path — `claude` fires a `MessageDisplay` hook carrying incremental, byte-faithful `delta`s of the raw reply (they concatenate exactly to the final text, and stay prefix-stable), on the subscription pool, without `-p`. Wiring it into OCP's SSE is tracked as backlog item #2. What is *not* available is token-by-token granularity (the hook fires once per rendered block — roughly one per paragraph, list item, or code block, so the count scales with answer length) — which is plenty for SSE. Evidence: [`docs/plans/2026-07-13-tui-latency/streaming-spike.md`](docs/plans/2026-07-13-tui-latency/streaming-spike.md).
- **No real token streaming.** TUI-mode buffers the full response then replays it as chunked SSE. You will see a delay then the complete response rather than real-time tokens.
- **Cache and singleflight work normally.** TUI-mode writes the buffered response to the cache on success; cache-hits skip the interactive turn entirely.
- **The host's `CLAUDE.md` / auto-memory is never injected.** OCP is a proxy — the proxied client (OpenClaw / your IDE) owns its own context and memory. TUI-mode always runs `claude` with `CLAUDE_CODE_DISABLE_CLAUDE_MDS` + `CLAUDE_CODE_DISABLE_AUTO_MEMORY`, so a `CLAUDE.md` on the OCP host can never leak into proxied turns (verified live; see #4). Built-in tool schemas + the interactive system prompt remain (the inherent ~2035K context floor of interactive mode); MCP is hard-disabled.
- **Authenticate via `CLAUDE_CODE_OAUTH_TOKEN` in a credential-isolated home (recommended).** tmux does not forward the parent process's env to the pane, so OCP sets the token explicitly on the spawned `claude` when `CLAUDE_CODE_OAUTH_TOKEN` is present. But passing the token is **not enough on its own**: interactive `claude` *prefers* `~/.claude/.credentials.json` over the env var (unlike the `-p` path), so a stale `credentials.json` would shadow the token. With the env token set and `OCP_TUI_HOME` unset, OCP therefore runs claude in a **credential-isolated home** (`$HOME/.ocp-tui/home`) that has **no `credentials.json`** — so the env token is the only credential and is authoritative, and claude never runs the token-refresh path (so the single-use refresh token can't be corrupted by the spawn/teardown cycle). On a long-running host the credentials.json path produced a permanent `Please run /login · API Error: 401` that re-login could not fix (the next spawn re-corrupted it); the isolated home ends that at the root. Transcripts land under the same isolated home, so the answer-reader is unaffected. Without the env token, claude falls back to the real home's `credentials.json` (byte-for-byte the previous behaviour). (The token is visible in `ps` on the pane command — acceptable for the single-user A-path; the multi-user B-path is refused at boot.) See ADR 0007 PR-C / PR-D amendments.
@@ -1041,35 +1041,6 @@ Then restart OCP. At boot you will see (with the env token set, isolated home au
- **Default path unchanged.** Unset `CLAUDE_TUI_MODE` and restart → `callClaude` / `callClaudeStreaming` are used again, byte-for-byte identical to today.
- **Concurrency is bounded separately.** TUI turns are heavy (per-request cold-boot + long wallclock), so the TUI path has its own limiter — `OCP_TUI_MAX_CONCURRENT` (default `2`), independent of `CLAUDE_MAX_CONCURRENT`. Excess turns queue; a full queue returns a 503. Tune it up only on a host that can run more interactive `claude` sessions at once.
### ⚠️ Latency: TUI mode has a ~6-second floor, and it is immovable
**TUI mode cannot serve real-time or interactive-latency consumers.** This is a hard property of the
path, stated plainly so you can rule it out before building on it:
| | measured |
|---|---|
| **TTFT floor (first token)** | **≈ 6 s** — immovable |
| cold boot → input bar ready | ~1 s (per request; not the bottleneck) |
| OCP's own overhead above the CLI | ~4 s (n=1 same-turn decomposition) |
| direct Anthropic API, same prompt (for scale) | 0.841.64 s |
The ~6 s floor is the `claude` CLI itself: it always injects the full Claude Code system prompt plus
its tool definitions before your prompt, on every turn, no matter what you ask. No flag removes it
(`--exclude-dynamic-system-prompt-sections` was measured: **no effect** on the floor). Extended
thinking is *not* the cause — `OCP_TUI_EFFORT` already defaults to `low`, which is what cuts a
formerly-inherited `xhigh` down to this floor and collapses its variance.
On top of the floor you pay the model's generation time (a function of output length). Progressive
output is not wired up **yet** (see "No real token streaming" above — it is achievable and planned),
so today a turn returns as one blob once generation completes. Note that streaming, when it lands,
will move the *first* byte earlier — it does **not** shorten the turn, and a consumer that needs the
complete answer gains nothing from it.
**Use TUI mode for**: batch, background, and latency-insensitive work where the subscription pool is
the point. **Do not use it for**: anything a person is waiting on interactively, or any consumer with
a sub-5-second budget. Full measurements and methodology:
[`docs/plans/2026-07-13-tui-latency/`](docs/plans/2026-07-13-tui-latency/).
### Monitoring drift via `/health`
`GET /health` includes a `tui` block so you can poll for a silent billing-pool drift (the top risk after the 6/15 flip — a lost TTY flipping `cc_entrypoint` from `cli` to the metered `sdk-cli` pool would still return answers but burn metered credits). The block is **always present** (with `enabled:false` when TUI-mode is off):
+3 -49
View File
@@ -1,9 +1,7 @@
# TUI-mode latency: measured floor, and the four things worth fixing
**Date**: 2026-07-13
**Status**: findings + backlog. **Superseded in part** — see the dated update boxes below.
Item #1 shipped ([#156](https://github.com/dtzp555-max/ocp/pull/156)); item #2 is **dead**
([`streaming-spike.md`](streaming-spike.md)); item #4 measured, **no effect**; item #3 stands.
**Status**: findings + backlog (no code changed yet)
**Measured on**: Mac mini / macOS 26.5.2 / Claude Code **v2.1.207** / Sonnet 5 / Claude Max subscription / **real-home mode** (no `CLAUDE_CODE_OAUTH_TOKEN`, no `OCP_TUI_HOME` in the service env)
**Evidence**: [`measurements.jsonl`](measurements.jsonl) — **n=15** (3 configs × 5) · banner captures [`billing-banner.txt`](billing-banner.txt) · harness [`floor.sh`](floor.sh)
@@ -49,18 +47,6 @@ All rows in [`measurements.jsonl`](measurements.jsonl); every number below is re
before returning anything. There is no streaming path. The ~20 s delta between this harness's
real TTFT and OCP's reported 3032 s is exactly that.
> **⚠️ 2026-07-13 correction — this decomposition attributes the ~20 s to the wrong thing.** It was
> inferred from the external 3032 s report, never measured *through* OCP. It has since been measured
> through a real OCP instance (TUI mode, `claude-sonnet-4-6`, the same ~1850-token prompt, n=5):
> **median 11.30 s** before [#156](https://github.com/dtzp555-max/ocp/pull/156), **9.55 s** after.
> Same-turn decomposition (baseline row `i=5`): **11.563 s** wall through OCP vs `turn_duration:
> 7.319 s` of CLI-internal time on that same turn → **OCP's own overhead ≈ 4.2 s** (n=1), **not
> ~20 s**. The rest of any larger number is the model *generating a long answer*,
> which the blocking wait does not cause and streaming would not shorten — it would only move the
> first byte earlier. The 3032 s figure therefore reflects a much longer output (and/or the
> then-inherited `xhigh` effort), not 20 s of OCP dead time. See
> [`streaming-spike.md`](streaming-spike.md) § "What streaming would have bought".
---
## ⚠️ Blocking constraint: `--bare` silently drops you off the subscription pool
@@ -119,28 +105,7 @@ the effort level silently changes if the operator ever switches to env-token mod
- **Risk**: none — banner confirms it stays on `Claude Max` (see `billing-banner.txt`).
- ⚠️ Do **not** reach for `--bare` to shave boot: see above.
### 2. Real streaming instead of blocking on turn-terminal — **ACHIEVABLE → [`streaming-spike.md`](streaming-spike.md)**
> **2026-07-13 update — the prereq spike was run. The answer is YES, but not from either source this
> item guessed at.** (a) The transcript grows at *event* granularity (the whole answer lands in one
> line, ~0.3 s before terminal) — dead. (b) The pane is a **rendered** view whose `capture-pane` text
> no longer contains the answer's source bytes (`## `, `**`, code fences are gone) — dead, and worse
> than "lossy": it is *not the model's text*. **But there is a third source neither this backlog nor
> the first spike considered: `claude` fires a `MessageDisplay` hook carrying incremental,
> byte-faithful `delta`s of the raw reply.** Verified live on a plain interactive TUI spawn (no `-p`),
> banner `· Claude Max`: 7 fires spread across generation, `concat(deltas) === T` **byte-exactly**
> (579 == 579), `T.startsWith(S)` true at every step, `## ` / `**` / ```` ```javascript ```` all
> present in the deltas. Granularity is block-level (~57 chunks/answer), not token-level — plenty for
> SSE. **Build it.**
>
> ⚠️ Two corrections to this item as written: the **"~20 s" is wrong** (inferred from an external
> report, never measured through OCP — the same-turn decomposition puts OCP's own overhead at **~4 s**,
> n=1), and **streaming moves the first byte, not the last** — so a consumer needing the *complete*
> answer (the JSON-card case that motivated this) gains **nothing** from it. Build it for
> progressively-rendering consumers, not as a throughput win.
>
> Full evidence + implementer caveats (the hook is `forceSyncExecution` — claude BLOCKS on it):
> **[`streaming-spike.md`](streaming-spike.md)**. Original framing preserved below.
### 2. Real streaming instead of blocking on turn-terminal — **the big one (~20 s)**
Today `runTuiTurn` blocks on the transcript until the turn is *finished*. The pane is already
rendering tokens incrementally the whole time — this harness proves you can observe first token
@@ -167,18 +132,7 @@ the background) amortizes it to zero for any workload below the pool refill rate
#148 — pooled panes must not look like zombies to the sweep.
- Lower priority than #1 and #2: it is the smallest slice.
### 4. Trim the prefill — ~~probably not worth it~~ **MEASURED: no detectable benefit. Do not adopt.**
> **2026-07-13 update.** `--exclude-dynamic-system-prompt-sections` was measured with the same
> harness (`floor.sh`, n=5, Sonnet 5, on top of `--effort low`): **TTFT median 6.39 s**
> (5.8710.54 s) vs **6.17 s** (5.876.44 s) for `--effort low` alone — i.e. **0.22 s worse, inside
> the noise band**, with one worse outlier; dropping that outlier does not change the verdict. n=5
> cannot prove "zero", only "no benefit detectable above noise" — but there is also a **mechanistic**
> reason not to expect one: `--help` says the flag *"Improves cross-user prompt-cache **reuse**"*, and
> **OCP is single-user** — there is no cross-user cache to share, so the flag has nothing to buy here.
> The banner stayed on `· Claude Max` (no billing-pool drop), but there is no win to bank. The ~6 s
> floor stands as stated below. Raw rows: [`prefill-spike-measurements.jsonl`](prefill-spike-measurements.jsonl).
### 4. Trim the prefill — **probably not worth it; know the floor**
After #1#3, the floor is **~6 s**, and it does not go lower. `claude` always injects the full
Claude Code system prompt + tool definitions (thousands to tens of thousands of prefill tokens)
@@ -1,7 +0,0 @@
{"hook_event_name": "MessageDisplay", "index": 0, "final": false, "delta": "## Mutex\n\n"}
{"hook_event_name": "MessageDisplay", "index": 1, "final": false, "delta": "A **mutual exclusion lock** prevents concurrent access to a shared resource, ensuring only one thread runs the critical section at a time.\n\n"}
{"hook_event_name": "MessageDisplay", "index": 2, "final": false, "delta": "- Acquiring a locked mutex blocks the caller until the current holder releases it.\n"}
{"hook_event_name": "MessageDisplay", "index": 3, "final": false, "delta": "- Failing to release a mutex causes a deadlock, freezing all waiting threads.\n\n```javascript\nconst { Mutex } = require('async-mutex');\n\nconst mutex = new Mutex();\n"}
{"hook_event_name": "MessageDisplay", "index": 4, "final": false, "delta": "let counter = 0;\n\nasync function increment() {\n const release = await mutex.acquire();\n try {\n"}
{"hook_event_name": "MessageDisplay", "index": 5, "final": false, "delta": " counter++; // only one caller here at a time\n } finally {\n release();\n }\n}\n"}
{"hook_event_name": "MessageDisplay", "index": 6, "final": true, "delta": "```"}
@@ -1,5 +0,0 @@
{"i":1,"tag":"effort-low-exclude-dynamic","model":"claude-sonnet-5","extra_args":"--effort low --exclude-dynamic-system-prompt-sections","prompt_chars":7451,"boot_ms":934,"ttft_ms":5867,"complete_ms":9953}
{"i":2,"tag":"effort-low-exclude-dynamic","model":"claude-sonnet-5","extra_args":"--effort low --exclude-dynamic-system-prompt-sections","prompt_chars":7451,"boot_ms":1275,"ttft_ms":6388,"complete_ms":9874}
{"i":3,"tag":"effort-low-exclude-dynamic","model":"claude-sonnet-5","extra_args":"--effort low --exclude-dynamic-system-prompt-sections","prompt_chars":7451,"boot_ms":874,"ttft_ms":10537,"complete_ms":11782}
{"i":4,"tag":"effort-low-exclude-dynamic","model":"claude-sonnet-5","extra_args":"--effort low --exclude-dynamic-system-prompt-sections","prompt_chars":7451,"boot_ms":1170,"ttft_ms":6379,"complete_ms":9947}
{"i":5,"tag":"effort-low-exclude-dynamic","model":"claude-sonnet-5","extra_args":"--effort low --exclude-dynamic-system-prompt-sections","prompt_chars":7451,"boot_ms":1329,"ttft_ms":6443,"complete_ms":9884}
@@ -1,256 +0,0 @@
# Backlog #2 (real streaming): **achievable** — via the `MessageDisplay` hook
**Date**: 2026-07-13
**Status**: prereq-spike result. **Streaming IS achievable on the TUI path**, byte-faithfully, on the
subscription pool. Three obvious sources are dead ends; a fourth one works.
**Scope**: answers the prereq spike that [`README.md`](README.md) § "Backlog #2" demanded *before* any
streaming design:
> **Prereq spike (do this before designing anything)**: does the transcript JSONL grow *during* a
> turn, or only at the end? If only at the end, (a) is dead and you are stuck with (b).
The answer: **(a) is dead, (b) is dead — and you are not stuck with either.** The CLI exposes its own
streaming interface as a **hook**, which the backlog did not consider.
**Measured on**: Mac mini / Claude Code **v2.1.207** / Sonnet 4.6 + Sonnet 5 / Claude Max /
real-home mode. Every claim below is reproducible from the commands given.
> **Honesty note on how this document was produced.** Its first version concluded the exact opposite —
> "streaming is not achievable; the CLI exposes no byte-faithful incremental source" — and was **wrong**.
> An adversarial reviewer, commissioned specifically to *refute* it, found `MessageDisplay` on a second
> pass; its own first pass had enumerated the hook registry with a truncated grep (it reported 21
> events — there are **30**). Both the wrong conclusion and its refutation are preserved here, because
> "we checked, it's impossible" is the most expensive kind of claim to get wrong: it closes a door and
> nobody re-opens it.
---
## ✅ The source that works: the `MessageDisplay` hook
`claude` fires a **`MessageDisplay`** hook as it renders each block of the assistant's reply. The
payload carries the **raw markdown source** of an incremental `delta`, plus a monotonic `index` and a
`final` flag:
```json
{ "hook_event_name": "MessageDisplay",
"turn_id": "6cb31d21-…", "message_id": "84ab9832-…",
"index": 0, "final": false, "delta": "## Mutex\n\n" }
```
*(payload also carries `session_id`, `transcript_path`, `prompt_id`, `cwd`)*
Registered as an ordinary command hook via `--settings` on a **plain interactive TUI spawn** (no `-p`,
no `--bare`), `claude-sonnet-4-6`, `--effort low`. Banner verified:
`▝▜█████▛▘ Sonnet 4.6 with low effort · Claude Max`**subscription pool, not metered billing**.
One live turn — 7 fires, spread across generation:
```
index=0 final=false len= 10 '## Mutex\n\n'
index=1 final=false len= 140 'A **mutual exclusion lock** prevents concurrent access to a shar…'
index=2 final=false len= 83 '- Acquiring a locked mutex blocks the caller until the current h…'
index=3 final=false len= 163 '- Failing to release a mutex causes a deadlock, freezing all wai…'
index=4 final=false len= 96 'let counter = 0;\n\nasync function increment() {\n const release =…'
index=5 final=false len= 84 ' counter++; // only one caller here at a time\n } finally {\n …'
index=6 final=true len= 3 '```'
```
**Every invariant a proxy needs — all hold:**
| requirement | result |
|---|---|
| **byte-faithful** — deltas are the model's *source*, not the rendered pane | ✅ `## `, `**`, ```` ```javascript ```` all present in the deltas |
| **exactness** — `concat(deltas) === T` (the transcript-authoritative text) | ✅ **true**, 579 == 579 bytes |
| **prefix-stable** — `T.startsWith(concat(deltas[0..n]))` at every n | ✅ **true at all 7 steps** |
| **incremental** — arrives during generation, not at the end | ✅ 7 fires spread across the turn |
| **no `-p`** — stays out of the metered `sdk-cli` pool | ✅ plain interactive TUI |
| **subscription pool** | ✅ banner `· Claude Max` |
This is exactly the contract a streaming design needs: deltas forward straight into SSE
`delta.content` chunks, and the transcript's final text `T` stays a cheap end-of-turn assertion
(`concat === T`) instead of a reconciliation problem.
### Caveats for the implementer
- **Block-level granularity, not token-level** — the hook fires **once per rendered block** (roughly one
per paragraph / list item / code block), so the chunk count **scales with answer length**: 7 fires for a
~600-byte answer, **18 for a ~2 KB one**. Plenty for SSE (`delta.content` has no minimum size), but do
not promise token-by-token output, and do not hard-code any assumption about chunk count.
- **🔴 The sink MUST be keyed by `session_id` — this is live TODAY, not a future concern.**
`OCP_TUI_MAX_CONCURRENT` defaults to **2**, so **two `claude` processes already run concurrently**. One
hook command writing to one shared sink would **interleave deltas from two different turns into one
stream** — request A's client receiving request B's text, the worst failure a proxy can have, and one a
single-request test will never surface. The payload carries `session_id` (and `turn_id` / `message_id`),
so demux is easy: derive the sink path from `session_id` (`<dir>/<session_id>.jsonl`) and read only your
own turn's file. This *also* keeps the design **warm-pool compatible**, because a pre-booted pane's
session-id is fixed at boot — one static hook script serves every pane. **Test it with ≥2 concurrent
streaming requests carrying distinguishable prompts and assert zero cross-contamination.**
- **⚠️ `forceSyncExecution: true` in the hook's source — `claude` BLOCKS on the hook.** A slow hook
adds latency to *every* delta. The hook must write and exit immediately (e.g. write to a FIFO / unix
socket that OCP reads; never work inline). **Measure the added per-delta latency.**
- **Thinking blocks appear to be excluded — but this is NOT yet stress-tested. Verify before shipping.**
The exclusion is inferred from `content.map(c => c.type === "text" ? c.text : "")` — but that snippet is
from the **`final:true`** call site, not the incremental one. Four live turns (incl. two at `--effort
high`) showed no thinking text in any delta and `concat === T` held — **but each transcript's thinking
block was empty (`thinking:""`, 0 chars)**, so the exclusion was never actually stressed. **The failure
mode is severe**: if thinking deltas *do* fire on some config (Opus, `xhigh`), `concat(deltas) !== T`
**and OCP streams the model's private reasoning to the caller**. The end-of-turn `concat === T` assertion
would *detect* that but **cannot prevent** it — SSE deltas cannot be un-sent. **Before shipping, run a
turn on a model+effort that produces substantive thinking** (a hard reasoning prompt on Opus / `xhigh`)
and confirm both (a) no thinking text in any delta and (b) `concat === T` still holds.
- OCP already owns the spawn (isolated HOME, its own flags), so injecting `--settings` with a
`MessageDisplay` hook sits inside the existing architecture.
- **`ALIGNMENT.md`**: this consumes `claude`'s **own** hook surface as emitted — forwarding, not
inventing. Not a new endpoint, not a fabricated protocol. (Class B / ADR 0007 — the TUI spawn is
OCP-owned; no `cli.js` citation applies.)
### Reproduce in 60 seconds
```bash
# hook script: append the payload (arrives on stdin) and exit immediately
printf '#!/bin/bash\ncat >> "$MD_LOG"; printf "\\n" >> "$MD_LOG"; exit 0\n' > /tmp/h.sh && chmod +x /tmp/h.sh
echo '{"hooks":{"MessageDisplay":[{"hooks":[{"type":"command","command":"MD_LOG=/tmp/deltas.jsonl /tmp/h.sh"}]}]}}' > /tmp/s.json
# plain interactive claude in tmux (prefix NOT ocp-tui-*, and never kill-server)
tmux new-session -d -s md-probe -x 220 -y 50 \
"claude --model claude-sonnet-4-6 --effort low --session-id $(uuidgen) --settings /tmp/s.json"
# …wait for '? for shortcuts', paste a markdown-producing prompt, press Enter…
jq -r '"\(.index) \(.final) \(.delta|@json)"' /tmp/deltas.jsonl # incremental raw-markdown deltas
# then assert: concat(deltas) == extractLatestAssistantText(<transcript>.jsonl)
```
---
## The three dead ends (still worth knowing — they say what NOT to build)
### (a) Incremental transcript reads — **dead: event granularity, not token granularity**
The transcript JSONL *does* grow during a turn, but one **whole event at a time**; the assistant's text
event is written as **one complete line**, appearing only ~0.3 s before the terminal `turn_duration`.
Observed (session `efd5b161`, `turn_duration: 7319 ms`):
```
#6 t+0.0s type=user (the prompt)
#15 t+4.7s type=assistant blocks=thinking
#16 t+7.0s type=assistant blocks=text ← the ENTIRE answer, in one line
#21 t+7.3s type=system subtype=turn_duration ← terminal
```
Cross-checked at **20 ms polling + `fs.watch`** (25× finer): a partial line **never touches disk** —
one write, `+1` line, carrying the complete answer. Also forced with the undocumented
`CLAUDE_CODE_INCLUDE_PARTIAL_MESSAGES=1`: still 1 assistant event, 0 partials (interactive mode has no
stream-json *sink* for it to write to).
**The transcript is still needed** — as the terminal-turn signal, as the authoritative `concat === T`
check, and as the input to the existing honesty gates (auth-banner detection, `truncated`). It is just
not the *streaming* source.
### (b) `tmux capture-pane` diffing — **dead: the pane is a RENDERED view, not the text**
The backlog expected to fall back to this, calling it "lossy … (wrapping, scrollback, spinner lines)".
The loss is far worse than formatting noise: **the pane does not contain the answer's source bytes at
all.** The TUI *renders* markdown, and `capture-pane -p` strips the ANSI that rendering produced.
Same turn, same lines:
```
TRANSCRIPT (authoritative T): PANE (capture-pane -p -J -S -500):
'## Semaphore' '⏺ Semaphore' ← heading marker gone
'' ''
'A **semaphore** is a synchro…' ' A semaphore is a synchro…' ← bold markers gone, indented
```
| token in the answer | in `T` | in the pane's answer region |
|---|---|---|
| `## ` (ATX heading) | yes | **no** — rendered as `` |
| `**` (bold markers) | yes | **no** — rendered to ANSI bold, then stripped by `-p` |
| ` ```javascript ` (fence + language) | yes | **no** — fence and language tag both gone |
| `- ` (list item) | yes | yes |
*(A literal `**` does appear elsewhere in the pane — in the **prompt echo**, because the prompt asked
for bold. Not in the answer.)*
**`capture-pane -e` (keeping the ANSI) does not rescue it — the inverse is provably non-unique.**
With `T` = ``"## Alpha\n\n**bravo**\n\n```javascript\nlet x=1;\n```"``:
```
⏺\e[39m \e[1mAlpha\n\n\e[0m \e[1mbravo\n\n\e[0m \e[34mlet\e[39m x=\e[32m1\e[39m;
```
`## Alpha` → **SGR 1 (bold)**. `**bravo**` → **SGR 1 (bold)**. *Identical ANSI* — an H2 and a bold span
are indistinguishable, never mind `**` vs `__`. The fence and its `javascript` tag are consumed by the
syntax highlighter into colours; recovering the tag would mean inverting a highlighter, and
`let x=1;` is valid in several languages.
So `T.startsWith(paneText)` is **false** — raw and indent-stripped, on essentially every markdown
answer. A proxy streaming pane text would be streaming **something the model did not say**. With
`MessageDisplay` available there is no reason to go near it.
### (c) `--debug-file` — **dead: it logs stream *timing*, never stream *content***
Worth stating precisely, because a casual check misleads in **both** directions here.
The default log level is `debug`, which **suppresses every `verbose` site**. Raise it and per-chunk
lines *do* appear, spread across generation:
```bash
CLAUDE_CODE_DEBUG_LOG_LEVEL=verbose claude --debug-file /tmp/d.log …
```
```
05:51:11.088 [VERBOSE] [shoji-engine] yield stream_event/- ← 16 of these, mid-turn,
05:51:11.537 [VERBOSE] [shoji-engine] yield stream_event/- over ~3.9 s of generation
05:51:15.192 [DEBUG] [shoji-engine] turn 1 end (usage in=575 out=255 api=6736ms stop=end_turn resultLen=857)
```
**But they carry no payload** — the format is `yield <type>/<subtype>`, a bare presence marker. Run with
no category filter (i.e. all categories) at verbose level: `content_block_delta` = **0**, `text_delta` =
**0**, `content_block_start` / `message_start` = **0**. The only byte-exact text in the log is the
end-of-turn `Stop` hook payload (`"last_assistant_message":"## Title\n\n**alpha bravo charlie**"`) —
transcript granularity. The log tells you **when** tokens arrive, never **what** they are. It is also
~2.7 MB per turn.
### Also checked, also not the answer
| candidate | outcome |
|---|---|
| `--output-format stream-json` (the one interface that emits `text_delta`) | **requires `--print`/`-p`** → `cc_entrypoint=sdk-cli` → the **metered** credit pool, which is exactly what TUI mode exists to avoid. Reproduced live. |
| `--input-format stream-json` | `Error: --input-format=stream-json requires output-format=stream-json` → same gate. |
| `CLAUDE_CODE_INCLUDE_PARTIAL_MESSAGES=1` (undocumented) | No stream-json sink in interactive mode → no partials. Banner stayed `· Claude Max`. |
| `sessionMirror` (undocumented) | Gated on `outputFormat === "stream-json"` → the `-p` family. |
| `--sdk-url` (hidden) | Forces stream-json + non-interactive → `sdk-cli`. *(inferred from the minified bundle; not banner-tested)* |
| `~/.claude/sessions/<pid>.json` | Registry metadata only (`{pid, sessionId, cwd, status, version, entrypoint:"cli", kind:"interactive"}`). No assistant text. *(Its `entrypoint:"cli"` incidentally confirms the TUI path stays on the subscription pool.)* |
| `~/.claude/history.jsonl` | User prompts only; the answer text is absent. |
| Asking the model to emit plain text (so the pane renders faithfully) | Would mean **mutating the caller's prompt** — a correctness violation for a proxy, and still not byte-faithful (wrapping + indent remain). Rejected. |
---
## Value: what streaming actually buys (read before building)
Streaming is *possible*. Whether it is *worth it* depends on the consumer, and the honest answer is
uncomfortable:
- **Streaming never makes the answer arrive sooner. It moves the *first* byte, not the *last*.** The
final token lands at the same wall-clock moment either way.
- So a consumer that must have the **complete** answer before it can act — e.g. one parsing a structured
JSON reply, **which is exactly the 知音 AI use case that motivated this entire investigation** — gains
**nothing at all**. Only a **progressively-rendering** consumer (a chat UI) gains.
And the number the backlog attached to this item was wrong:
- The backlog's "~20 s" was inferred from an external 3032 s report, **never measured through OCP**.
Measured through a real OCP instance (TUI mode, `claude-sonnet-4-6`, ~1850-token prompt, n=5):
**median 11.30 s** before [#156](https://github.com/dtzp555-max/ocp/pull/156), **9.55 s** after.
- **Same-turn decomposition** (baseline row `i=5`): **11.563 s** wall through OCP vs `turn_duration:
7.319 s` of CLI-internal time on that same turn → **OCP's own overhead ≈ 4.2 s** (n=1, baseline
`effort=high` config). *Caveats*: n=1; and `turn_duration` is the CLI's internal duration of an
**OCP-driven** turn, not a separate "native" baseline. Do **not** subtract this `effort=high` 7.3 s
from the `effort=low` 9.55 s median — a low-effort turn generates faster, so mixing them
*understates* the overhead.
- So OCP's own overhead is **single-digit seconds**, not ~20 s. The rest of any large number is the
model generating a long answer — which streaming hides but does not shorten.
**Recommendation**: build it — the contract is clean and the cost is small — but size the expectation
honestly. It is a *perceived-latency* feature for progressively-rendering consumers, not a throughput
win, and it does not move the **~6 s TTFT floor** ([`README.md`](README.md)) that rules TUI mode out for
interactive-latency consumers regardless.