EMBED WITNESS

The embed witness: one ChatGPT session on the candidate

For Mateo, by hand. PR 6 of the embed stage decision §9; the checks are its §10. It settles the real-host half of LIVE-004 and answers the five host questions that were never recorded. One session, desktop web, DevTools open on RISE's frame. It is what LIVE-002 did, on the stage instead of the bar.

1. The candidate

The exact candidate is the tip of main once PR 6 is merged. Read it, and check that the stage is in it:

git fetch origin && git rev-parse origin/main
git log --oneline origin/main | grep -E '#(423|428|429|432|435|439)\)'   # six lines

Check that SHA out in its own worktree (never the main folder), npm ci, and keep the SHA for the record.

2. Deploy the demo Worker from it

As LIVE-002 did (CHATGPT-DEMO.md, setup). In wrangler.demo.jsonc, for the session only: "workers_dev": true, "MCP_ENABLED": "true", "MCP_GATE0": "false" (LIVE-002 advertised rise_present alone), and "MCP_WITNESS": "true", which makes the Worker serve the relay with /live?embed=mcp&log=host so the log is on from the first hello. It is a session-only value: never in wrangler.production.jsonc, never committed. Then, from the worktree:

npm run build
node --input-type=module -e 'import {execFileSync} from "node:child_process"; import {writeFileSync} from "node:fs"; const sha=execFileSync("git",["rev-parse","HEAD"],{encoding:"utf8"}).trim(); writeFileSync(`dist/release-${sha}.txt`,`${sha}\n`);'
npx wrangler deploy --config wrangler.demo.jsonc

Write down the HTTPS origin and the version id Wrangler prints. The MCP URL is that origin plus /api/mcp. Before connecting: curl -s https://<origin>/release-<sha>.txt prints the SHA; curl -sI https://<origin>/live carries X-Frame-Options: DENY and curl -sI "https://<origin>/live?embed=mcp" does not. Do not commit the config change; step 9 restores it.

3. Connect in ChatGPT developer mode

From the official page Connect and test your plugin, read 2026-10-05 ("Account and workspace policies apply to adding and using custom MCP servers"):

1. Open ChatGPT Plugins at https://chatgpt.com/plugins. If RISE Demo from LIVE-002 is still there, open it and select Refresh ("Start a new conversation and rerun the affected tests"); skip to 5.
2. Select the plus button, then Add custom MCP server.
3. Name it RISE Demo; under Connection, enter the MCP server URL https://<origin>/api/mcp (RISE's path, not /mcp); no authentication.
4. Review the risk warning, select I understand and want to continue, then Create as a plugin.
5. Start a new conversation. The page says: type @ in the prompt box and select the plugin.

Developer mode unavailable or a signed-out browser is an access blocker, not a RISE failure. Record it as such.

4. The one conversation

Type, after @RISE Demo:

Use RISE to explain why a black hole is black in three passages, about 80 plain words each. Use the attractor visual in every passage. This is a controlled embed witness: call rise_present once and leave playback to the reader.

The card is the poster: the title and Play, nothing playing.

5. Open the console and filter rise-host

The widget is ChatGPT's sandboxed frame holding RISE's relay, which frames RISE's page on the demo origin; with MCP_WITNESS set (step 2) that page is /live?embed=mcp&log=host, so the log is already on.

1. Open DevTools (F12) on the ChatGPT tab. Console, then the context picker at the top left of the console (it says top).
2. Pick the inner frame: the context whose URL is <origin>/live?embed=mcp&log=host. Type rise-host in the console filter. The first line, "rise-host":"initialize", is the hello's context.

Fallback only, if the frame's URL lacks &log=host (the Worker was deployed without the value): pick the relay frame, the one whose document holds iframe#app, run document.getElementById('app').src += '&log=host', and watch whether the poster comes back (the inner page says hello again through the relay; whether ChatGPT answers a second hello is unknown). Say in the record which path was taken.

6. What to press and watch

Step	Watch
Poster	Title and Play; nothing playing; the visible card height with the DevTools ruler (select the relay's iframe#app in Elements; Computed → height)
Play	Narration; the words shown as spoken; the attractor; the gap from the press to the first word, by ear and the clock
Pause	The held sentence stays; nothing moves
Settings	Open the sheet. Intensity: the field dims or brightens live. Theme: pick Rose, the frame and the field recolour, As written gives them back. Still imagery: on, the field holds; off, it turns. Text size: L, the words grow. Close, then Play: the same reading resumes
The end	Finished, and Play again. Press it: the reading starts from the first word
Resize	Drag the window to about 560 wide, then wide (1280). Each "size-changed" line; whether the card's height follows it (step 7, question 3)
Reload	Reload the tab: the poster again, no autoplay. Open a new chat: no voice continues
Light mode	ChatGPT Settings → light. A screenshot of the card's edge against the thread
A phone, if possible	Developer-mode plugins are web-only in the record; if the plugin is reachable in the ChatGPT phone app, repeat Poster, Play, Pause there and keep its initialize line (platform, safeAreaInsets)

7. Reading the lines

Three kinds, one JSON object each, nothing else is instrumented. A field the host did not send is absent. stylesVariables is the keys of styles.variables, never the values.

{"rise-host":"initialize","containerDimensions":{…},"displayMode":"inline","availableDisplayModes":[…],"safeAreaInsets":{…},"theme":"dark","stylesVariables":["--font-sans",…],"platform":"web","deviceCapabilities":{…}}
{"rise-host":"context-changed","containerDimensions":{"maxHeight":520}}
{"rise-host":"size-changed","height":481}

Copy them out verbatim (select in the console, copy) into the record; they are the evidence. The five questions from the decision's §10, and what each answer changes:

Question	How	If …	then …
1. Is containerDimensions.height fixed at the hello?	the initialize line	fixed	the page fills it; the 481 floor matters only under 481, and then the Reader lane scopes the landscape block out by data-embed, first
2. containerDimensions.maxHeight against the visible card height after the first report	the line and the ruler	maxHeight < 481 at 560 wide	the same fallback: the floor is replaced by the data-embed exclusion
3. Is the size-changed height applied?	at 760 wide the line says 502; measure iframe#app	not applied	the inline height is the host's; the report stays, harmless, and the layout is checked at whatever height the host gives
4. Would a reported width be applied?	once, from the inner frame's console: parent.postMessage({jsonrpc:'2.0',method:'ui/notifications/size-changed',params:{width:innerWidth-100}},'*'), then reload the tab to undo	applied	the stale-width reading of the LIVE-002 clipping is confirmed; width stays omitted
5. availableDisplayModes, and does an Expand affordance still show on the card with ['inline'] declared?	the line and the card's own chrome	the host still offers Expand	nothing changes now; a fullscreen layout is a later, additive PR

Also from §10: a non-zero safeAreaInsets.bottom means --safe-bottom is already applied, confirm it by eye; in the inner frame with the OS reduced-motion setting on, matchMedia('(prefers-reduced-motion: reduce)').matches false means the Still switch is the only channel, said in the LIVE-005 record; a dark card cut against a light thread means prefersBorder: true is considered (owner) and nothing else; the poster not returning on reload, or a voice outliving the closed thread, is a defect fixed before LIVE-004.

8. The record

Write docs/experiments/EMBED-STAGE-HOST-<date>.md in the shape of the LIVE-002 record, no account, conversation or credential details:

# Embed stage witness — <date>

Exact candidate `<sha>`; demo Worker `rise-chatgpt-demo` version `<id>`; endpoint `https://<origin>/api/mcp`; release marker checked before and after. Desktop web ChatGPT in <browser>, developer mode; the log switched on by <MCP_WITNESS | the DevTools fallback>.

## Host lines
(every rise-host line, verbatim, in order)

## The five questions
| Question | Observed | What changes |

## What was pressed and seen
| Step | Observed |

## Not established
(a phone, audible quality, anything skipped and why)

## Inert again
Version `<id>` reported No targets deployed; POST to the MCP URL returned 404.

Add its row to docs/README.md beside the LIVE-002 record, then the evidence row to LIVE-004 (kind: "observation"): read revision in docs/product/tasks/LIVE-004.json, write a patch file, run node scripts/roadmap.mjs update LIVE-004 --patch <file> --expect-revision <N> --summary "<text>", then node scripts/roadmap.mjs validate.

9. Make the Worker inert

As LIVE-002 did. In wrangler.demo.jsonc: "workers_dev": false, "preview_urls": false, "MCP_ENABLED": "false", "MCP_GATE0": "false", and MCP_WITNESS removed; then npx wrangler deploy --config wrangler.demo.jsonc, which reports No targets deployed. Check curl -s -o /dev/null -w '%{http_code}' -X POST https://<origin>/api/mcp is 404 (a 405 during edge propagation is not done yet; wait and retry). Then git checkout wrangler.demo.jsonc. The plugin entry in ChatGPT now points at an offline endpoint; remove it or leave it. Production is untouched throughout.

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Published from docs/plans/EMBED-WITNESS.md. Edits made here are overwritten on the next push to main.