# ISL `request_script_message` → caption text

**✅ Settled 2026-08-26.** Every mission-script message call resolves to the
dialogue line it plays. The 28 stage scripts are readable as dialogue.

## The link

Built-in **64** (`request_script_message`) takes one operand in slot 0: a
two-word symbol reference into **symbol table 1**. The symbol's name is a
message id such as `MSG_VOICE_D_257`. The text lives in the language pack's
IXUD blocks (`dat/GP_MAIN_GAME_<lang>.pak`) as a **named field** whose key is
`<id>_<page>_<line>`, read via the record/field table documented in
[idxd-container.md](idxd-container.md).

    MSG_VOICE_D_257  →  field key `MSG_VOICE_D_257_000_00`  →  "Katana! Damn it!"

## Evidence

Measured over all 28 `StageNN.ssb`:

| | |
|---|---|
| built-in 64 call sites | **2683** |
| slot 0 not staged | 0 |
| operand not in symbol table 1 | 0 |
| operand symbol type | **6** at all 2683 sites |
| distinct message names | 1338 |
| names with caption text at `_000_00` | **2683 / 2683 (100 %)** |

There is no residue: no call site takes a different operand shape, no name is
of a type other than 6, and no name is missing from the caption table. That
totality is the result — a partial rate would have meant the operand encoding
was only sometimes what I thought it was.

Name families and their share of call sites:

    MSG_VOICE  2407    MSG_ADAN  118    MSG_ACRO   82
    MSG_ADPL     38    MSG_TCAF   35    MSG_RHIN    3

`MSG_VOICE_*` is crew/wingman dialogue; the four-letter families are
ship-side announcements (`ACRO` = ACROPOLIS, `ADAN`/`ADPL` = ADAN,
`TCAF`, `RHIN` = Rhino flight).

## Page and line structure — and a correction to this page's first tool

**✅ Measured 2026-08-26**, on the English pack. A caption id is keyed
`<id>_<page>_<line>`:

* a **page** is one subtitle box, holding **3 or 4 wrapped lines** (4 506 pages
  of 4, 263 of 3 — no other width occurs);
* successive **pages are successive utterances**, and may be different
  speakers. A multi-page id is therefore a whole exchange, not one long line:

      MSG_DEMO_009  page 0  No way! There's more of them?
                    page 1  Rhino Leader to ACROPOLIS! There's a whole fleet of them now!
                    page 2  What? Is there any way you can get out of there?
                    page 3  If we get rid of those fighters, we can cut our way out of here.

Of 4 091 distinct ids, **452 span more than one page** (374 `MSG_VOICE`,
78 `MSG_DEMO`), up to 8 pages.

**This refuted the first version of `isl_dialogue.py`**, committed earlier the
same day, which read only page `000`. **356 of the 1338 script message names
are multi-page**, so a quarter of the dialogue it printed was silently
truncated to its opening utterance. The tool now walks pages until one is
empty. The 2683/2683 resolution figure above is unaffected — it counted ids
that *have* text, and every id does have a page `000` — but the *rendered*
text was incomplete, and the caveat this page originally carried ("whether any
id uses a page other than `000` is unmeasured") understated it as a question
when it was already a defect.

## Why this was not obvious earlier

The caption table only became readable on 2026-08-25, when `build_caption_text`
was switched from scraping adjacent string-pool tokens to reading the IXUD
**field** table — which took the extractable line count from 537 to 8800
(8800 of 8800 distinct keys). Before that the great majority of these 1338
names had no text to resolve *to*, and the 100 % figure was unreachable.

## What this does not settle

* **Which recording plays.** The caption is the *text*; the voice bank binding
  is a separate and still-unresolved question — see
  [voice-bank-leading-region.md](voice-bank-leading-region.md) and the
  known case of a generic line playing against a specific subtitle.
* **Which page a `MSG_DEMO_*` id belongs to.** The `DEMO` family is not called
  from the stage scripts at all — 78 of its ids are multi-page, so something
  else drives cutscene dialogue. That driver is unidentified.
* **The other five languages.** Only the English pack was swept.
* **Ordering.** The tool prints call sites in file order, which is *script*
  order, not necessarily *play* order — phases and branches are not resolved.

## Tool

    tools/re-capture/isl_dialogue.py <StageNN.ssb> [GP_MAIN_GAME_E.pak]

Sample output committed at [../data/isl-stage02-dialogue.txt](../data/isl-stage02-dialogue.txt)
(Stage 02, 213 message calls, 213 with text).