# Direct scenario editing — bounded implementation plan

Status: implementation and automated Windows checks passed in the isolated
`codex/scenario-direct` checkout, based on ab661f2. Production commit is d1d8f0b.
Independent review and native acceptance remain pending the root's Windows/Linux
trials. This does not complete the release or the separate process/chain work.

## Decisions

Extend the existing `behavior::Scene`; retain its derived lifeline columns and
ordered occurrence rows. No model/schema/layout records are added. Lifeline and
occurrence UUIDs remain distinct from represented work and global exchanges.

Select mode selects headers, stems, messages and occurrence boxes. A selected
occurrence has a reorder handle; dragging it chooses a visible slot in its same
parent sequence. It never reparents or changes lifeline columns. A Message tool
uses the existing MessageStyle, with Call + correlated reply initially selected.
Click-click or drag between represented lifelines captures a highlighted explicit
insertion slot `(parent, before occurrence or append)` and opens the existing
typed draft with those endpoints. Existing exchanges/calls are filtered against
the complete candidate at that slot and shown through search plus 24-item pages.
No compatible exchange produces an actionable retained draft, not a new global
exchange or a silently changed endpoint. Timer remains available as a local tool.

The canvas remains rendered while a bounded, independently scrollable form is
open. Values keep the existing qualified-path editor and lifecycle. Final creation
uses ordinary CreateElement plus SetSteps in one Batch; paired call/reply are
inserted together and undo together. Reordering uses SetSteps within the captured
parent. Existing core validation decides reply order, branch dominance, lifetime,
phase and endpoint compatibility. Failed preparation/source writes retain drafts.

Transient events capture document/scenario/revision/epoch, and the App validates
the current Behavior owner before handling them. Selection does not invalidate a
gesture within the same scenario. Escape, unfocus, context/tool change and pending
drafts cancel gestures. Ordered pointer events and captured window positions avoid
coalesced-click and changed-scroll-origin commits. No geometry is persisted.

Execution bars derive their ends from actual correlated reply positions; separate
conditional reply branches render their corresponding spans. Calls without a
visible reply use a short explicitly open activation, not a fabricated reply.

## Acceptance checks

Production-event tests cover hit priority, click-click/drag, scroll-origin changes,
Escape/unfocus/stale contexts and exactly one result per gesture. Planner/App tests
cover middle/operand insertion, paired identities, complete SetSteps ordering,
same-parent reorder, rejected reply-before-call, unchanged global exchanges, exact
source/model Undo, draft retention and bounded exchange/call controls. Run focused
and full desktop tests, strict all-target desktop Clippy and optimized build with
the dedicated `D:/CodexBuilds/Capella2-scenario-target` target.

Root native tasks (not yet performed):
1. Draw an existing exchange again into the middle of a scenario as Call+Reply;
   enter a qualified value, select both occurrences, Undo/Redo, save/reopen.
2. Insert inside an ALT/LOOP operand, reorder within it, reject a reply before its
   call, and inspect correlated execution bars and preserved occurrence identities.
3. Cancel drawing after scrolling/layout change, retry, retain typed values while
   navigation is blocked, and open/return from a referenced scenario. Verify at
   1440x900 and 1100x700 on Windows and Linux before scoped acceptance.

## Automated evidence — 2026-09-06

Source checkout: `D:/CodexBuilds/Capella2-scenario-direct`, production commit
`d1d8f0bbed5aa0112189138a1cc025affe26c09b`. Changes are confined to desktop
`app.rs`, `behavior.rs` and `behavior/scenario.rs`; no core model, persisted layout
or schema changes are included.

All commands used the dedicated `D:/CodexBuilds/Capella2-scenario-target` target
with `--locked --offline`:

- `cargo check -p oa-desktop --all-targets`: passed.
- `cargo test -p oa-desktop direct_`: 19 passed, including 13 new direct-scenario
  tests and six existing matching tests.
- `cargo test -p oa-desktop`: final source passed all 274 tests, zero failures or
  ignored tests. This includes exact source/model Undo, creation and reorder
  selection, rejected stale contexts, retained failed-write drafts, bounded
  contextual controls, scroll-origin cancellation and correlated activation spans.
- `cargo clippy -p oa-desktop --all-targets -- -D warnings`: passed.
- `cargo build -p oa-desktop --release`: passed.
- `git diff --check`: passed before the production commit.

Logs are under `D:/CodexBuilds/`: `Capella2-scenario-check.log`,
`Capella2-scenario-direct-tests.log`, `Capella2-scenario-desktop-final-tests.log`,
`Capella2-scenario-desktop-clippy.log` and `Capella2-scenario-desktop-release.log`.

Windows artifact:
`D:/CodexBuilds/Capella2-scenario-target/release/arcadia-studio.exe`,
20,345,856 bytes, SHA-256
`7CC6DCDB7ECC0C6B144137D31DB0BE9BC1555FEFAE6B465DAEABCF52DFE1A166`.
This artifact has not been native-tested. Widget-tree/event tests do not establish
visual usability, scrolling behavior or GPU rendering acceptance; the three native
tasks above remain required. Process/chain direct editing remains outside this
bounded implementation.