AC27 Editor MCP — Skill

1. What This Skill Enables

Control the AC27 Editor from Claude Code. Create, read, modify, and delete flights in the currently-open .acl schedule file. The user is responsible for opening and saving files via the editor UI — the MCP operates on whatever level is currently open.

2. Prerequisites

• Editor must be running (npm start or double-click the app). The API server auto-starts on 127.0.0.1:31415.
• A level must be open in the editor (user loads it manually via the UI).
• This skill file must be installed so Claude Code understands the domain. Download from GitHub and place at ~/.claude/skills/ac27-editor-mcp/SKILL.md.
• mcp/bridge.js must be accessible on disk. Clone the repo or download from GitHub.
• Node.js required to run the bridge.
• Claude Code configured (see below).

Dev setup (.mcp.json at project root — auto-detected):

{
 "mcpServers": {
 "ac27-editor": {
 "command": "node",
 "args": ["mcp/bridge.js"]
 }
 }
}

Packaged app setup (.mcp.json next to the .exe, with mcp/bridge.js in the same folder):

{
 "mcpServers": {
 "ac27-editor": {
 "command": "node",
 "args": ["./mcp/bridge.js"]
 }
 }
}

3. Chinese Language Support (中文支持)

Users may interact in Chinese. The editor has full bilingual data — this skill teaches you how to use it.

Airline Name Resolution (航空公司名称映射)

When a user says "国航" or "Air China", resolve to the 3-letter ICAO code.

Chinese Domestic Airlines (中国国内航司)

Chinese Name	English Name	ICAO	Common Aliases / Short Names
中国国际航空	Air China	CCA	国航
中国东方航空	China Eastern Airlines	CES	东航
中国南方航空	China Southern Airlines	CSN	南航
海南航空	Hainan Airlines	CHH	海航
国泰航空	Cathay Pacific	CPA	国泰
厦门航空	Xiamen Airlines	CXA	厦航
四川航空	Sichuan Airlines	CSC	川航
深圳航空	Shenzhen Airlines	CSZ	深航
山东航空	Shandong Airlines	CDG	山航
春秋航空	Spring Airlines	CQH	春秋
吉祥航空	Juneyao Air	DKH	吉祥
上海航空	Shanghai Airlines	CSH	上航
成都航空	Chengdu Airlines	UEA	成都
西藏航空	Tibet Airlines	TBA	西藏

Major International Airlines (主要国际航司)

Chinese Name	English Name	ICAO	Common Chinese Short Names
美国航空	American Airlines	AAL	美航
联合航空	United Airlines	UAL	美联航
达美航空	Delta Air Lines	DAL	达美
英国航空	British Airways	BAW	英航
法国航空	Air France	AFR	法航
汉莎航空	Lufthansa	DLH	汉莎 / 德航
阿联酋航空	Emirates	UAE	阿联酋 / 土豪航
全日本空输	All Nippon Airways	ANA	全日空
日本航空	Japan Airlines	JAL	日航
新加坡航空	Singapore Airlines	SIA	新航 / 星航
大韩航空	Korean Air	KAL	大韩
长荣航空	EVA Air	EVA	长荣
中华航空	China Airlines	CAL	华航
卡塔尔航空	Qatar Airways	QTR	卡航
土耳其航空	Turkish Airlines	THY	土航
西南航空	Southwest Airlines	SWA	西南
边疆航空	Frontier Airlines	FFT	边疆
夏威夷航空	Hawaiian Airlines	HAL	夏威夷
加拿大航空	Air Canada	ACA	加航
澳洲航空	Qantas	QFA	澳航
荷兰皇家航空	KLM	KLM	荷航
瑞士航空	Swiss	SWR	瑞航

How to resolve: Call get_airport_info → check constraints.airlineCode (the codes known for this airport). Match user intent to a code using the name↔code table above: "国航" → "Air China" → "CCA". If the user uses a short name not listed above, ask for or infer the 3-letter code (the same name→code map lives in src/utils/constants/airlines.js as AIRLINE_CODE_MAP).

Chinese Field Name Mapping (中文字段名映射)

When a user uses Chinese field names, translate to the API field key:

Chinese	API Field		Chinese	API Field
呼号	CallSign		航司	AirlineName
出发	DepartureAirport		机型	AircraftType
到达	ArrivalAirport		进场程序	Airway
停机位	Stand		注册号	Registration
跑道	Runway		语音	Voice
推出	OffBlockTime		语言	Language
起飞	TakeoffTime		航司代码	AirlineCode
落地	LandingTime		航班号	FlightNum
入位	InBlockTime

Chinese Phrase Translation Rules

• "把所有国航的航班改成01跑道" → modify_flights({match:{airline:"CCA"}, updates:{Runway:"01"}})
• "创建5个东航的出发航班" → build 5 flight objects with CallSign prefix "CES", type=departure
• "把停机位G5的航班注册号改成B-1234" → modify_flights({match:{stand:"G5"}, updates:{Registration:"B-1234"}})
• "删除所有14:00前的国泰到达" → get_flights({airline:"CPA", type:"arrival", timeBefore:"14:00"}) then delete_flights
• "出发" / "离港" = departure (has OffBlockTime + TakeoffTime)
• "到达" / "进港" = arrival (has LandingTime + InBlockTime)
• Time: "10点" → "10:00", "10点30分" → "10:30", "下午2点" → "14:00"

4. Flight Anatomy

• Arrival vs Departure: Arrivals have LandingTime + InBlockTime + DepartureAirport. Departures have OffBlockTime + TakeoffTime + ArrivalAirport.
• Callsign format: 3-letter ICAO airline code + flight number (e.g., CCA1234).
• The 15 fields: CallSign, DepartureAirport, ArrivalAirport, Stand, Runway, OffBlockTime, TakeoffTime, LandingTime, InBlockTime, AirlineName, AircraftType, Airway, Registration, Voice, Language.
• AirlineName stores the 3-letter airline code, NOT a display name — the game format uses codes (e.g. "CCA", "UAL"). create_flights fills it from the callsign prefix when left empty, so it can be omitted safely.
• Departure/arrival is derived server-side: create_flights sets an internal isDeparture flag from OffBlockTime presence; the saved ACL leg (InitialArrival vs InitialDeparture) follows it. get_flights rows include this isDeparture boolean.
• Time format: HH:MM:SS (or HH:MM shorthand). Times are wall-clock times within the scenario config range.
• Cascade rules (applied server-side on modify): Changing AirlineCode rebuilds CallSign, resets Registration to first valid (the aircraft type is independent and preserved), and syncs AirlineName to the new code. Changing FlightNum rebuilds CallSign. Changing Runway resets Airway to first valid STAR.
• Registration format: Country prefix + hyphen + alphanumeric (e.g., B-1234, N123AB).

5. Validation Rules — How to Create Valid Flights

The server WILL reject invalid requests with a 422 error containing error.details. Follow these rules to avoid rejection.

Rule 1: Airline code must be known. Check constraints.airlineCode from get_airport_info. If the code isn't listed, the flight is rejected.

Rule 2: Flight number must be canonical (if known). Check constraints.flightNumbers[airlineCode]. If the airline has a list, use a number from it. If no list, any numeric string is accepted.

Rule 3: Aircraft type is independent of the airline. Choose any type from constraints.aircraftTypes (the game's full profiled type pool) regardless of the callsign's airline. constraints.airlineAircraftCompat is informational only.

Rule 4: Airway/STAR must be compatible with runway (arrivals only). Check constraints.runwayStarCompat[runway]. If the runway has a list, the airway MUST be from it.

Rule 5: Registration must be valid for (airline, aircraft) pair. Check constraints.registrationsByPair['AAL|A320']. If the pair has a list, the registration MUST be from it. Also: same registration on 2+ departures OR 2+ arrivals = rejected.

Rule 6: Times must be within config range. Check configTimeRange. All times must fall within this window. LandingTime < InBlockTime. OffBlockTime < TakeoffTime.

Rule 7: Stand conflicts are checked. Two departures on the same stand always conflict. A departure and arrival on the same stand conflict when OffBlockTime >= LandingTime.

Rule 8: How to construct valid flight objects (14-step procedure):

1. Call get_airport_info. Check cacheReady — if false, warn user.
2. Choose an airline code from constraints.airlineCode.
3. Choose a flight number from constraints.flightNumbers[airlineCode]. Combine into CallSign = airlineCode + flightNumber.
4. Choose any aircraft type from constraints.aircraftTypes (airline-independent).
5. Choose a runway from constraints.flatLists.Runway.
6. Choose a stand from constraints.flatLists.Stand.
7. For arrivals: choose an airway from constraints.runwayStarCompat[runway]. For departures: leave Airway empty.
8. Choose a registration from constraints.registrationsByPair['airlineCode|aircraftType'].
9. Set AirlineName to the 3-letter code itself (e.g. "CCA") — the game stores codes, not display names. May be left empty; the server fills it from the callsign prefix.
10. Set times within configTimeRange. Arrivals: LandingTime < InBlockTime. Departures: OffBlockTime < TakeoffTime.
11. Set DepartureAirport (arrivals) or ArrivalAirport (departures) to the current airport ICAO.
12. Set Voice and Language from constraints.flatLists. Follow the editor's region convention: zh if the airport ICAO starts with Z (China), else en; Voice — pick randomly from the airport's pool (already region-appropriate: CN-* voices at Z airports, e.g. Yeager at US airports).
13. Build the complete 15-field object and pass to create_flights({flights: [obj, ...]}).
14. If 422: read error.details, fix the specific fields, retry.

Rule 9: Server-side validation is the backstop. If you miss a constraint, the server rejects with error.details containing the valid options for the rejected fields. You don't need to re-fetch get_airport_info to recover.

6. Tool Reference

get_editor_status

No parameters. Returns: editorReady, currentPath, currentAirport, flightCount, arrivalCount, departureCount, configStartTime, configEndTime, isDemo, modified, hasTimelines.

get_airport_info

No parameters. Returns: cacheReady, currentAirport, configTimeRange, and constraints with all validation maps (flatLists, airlineCode, flightNumbers, aircraftTypes, airlineAircraftCompat, runwayStarCompat, registrationsByPair, timeRules, standRules, registrationRules). Call this before any create/modify.

create_flights

{flights: [{CallSign, DepartureAirport, ArrivalAirport, Stand, Runway, OffBlockTime, TakeoffTime, LandingTime, InBlockTime, AirlineName, AircraftType, Airway, Registration, Voice, Language}]}. All 15 fields required per flight. Returns {success, created} or 422 with error.details. Server-side enrichment: isDeparture is derived from OffBlockTime presence (drives which leg the save writes); AirlineName defaults to CallSign.substring(0, 3) when empty.

get_flights

{type?, airline?, callsign?, stand?, runway?, aircraftType?, timeAfter?, timeBefore?, limit?, offset?}. Returns {success, flights, total}. Rows carry the 15 fields plus an isDeparture boolean (internal flag the save uses to choose the leg).

modify_flights

{match: {callsigns?, callsign?, airline?, type?, stand?, runway?, aircraftType?}, updates: {Stand?, Runway?, OffBlockTime?, ...}}. Server applies cascade logic. Returns {success, matched, modified} or 422.

delete_flights

{match: {callsigns?, callsign?, airline?, type?, stand?, runway?, aircraftType?}}. Returns {success, deleted}.

get_validation_issues

No parameters. Returns {success, issues, duplicateCallsigns, standConflicts, duplicateRegistrations}.

send_voice_command

{transcript: string}. Parses a spoken-style sentence against the live aircraft list (same pipeline as the PTT mic — parseVoiceTranscript; typed input gets the parser's fuzzy matching for free — "turn lef heading 360" parses, and the two semantic inversions ascend→descend / decrease→increase stay excluded). Waypoint target set for fly direct to X comes from the airport cache (approachData.airwayNodes — same source as the AirMap's Waypoints layer; the [VOICE-PARSE] log line reports wps=N). Dispatches the patch frames to the game in real time. Requires the game + BepInEx plugin running so UDP telemetry exists. Returns {success, callsign, renderedLine, sent: [{type, label}], notices, aircraft}. Selection-only (bare callsign) → success:true, sent:[]. Fails with success:false when no aircraft matches, or the aircraft is not on the approach channel (controlSeat 5). Each parse also prints a [VOICE-PARSE] line to the editor's main-process log (npm start terminal). Example transcripts: "CSC6918: climb and maintain 9000, reduce speed to 180 knots", "AAL218: fly direct to BELTT" (language auto-detected, en/zh).

7. Workflow Rules

• Always check status first — call get_editor_status at the start of any task. If editorReady is false, tell the user to open a level.
• Get airport info before creating/modifying — call get_airport_info. Follow the 14-step procedure in Rule 8.
• Verify after modifying — call get_flights after changes to confirm the result.
• Validate after changes — call get_validation_issues so the user knows about issues before saving.
• Handle 422 errors gracefully — read error.details, fix fields, retry. The error tells you exactly what to fix.
• Remind user to save — the MCP cannot save files. Remind the user to click Save in the editor UI.
• Handle missing data — if cacheReady is false or constraint maps are empty, warn the user that validation may be limited.

8. Composition Examples

English Examples

Example A: "Create 10 AAL departures, 1 min apart, randomize aircraft"

1. get_editor_status → confirm level loaded, note currentAirport
2. get_airport_info → get constraint map (aircraft type pool, flight numbers, registrations)
3. Construct 10 flight objects (LLM internally):
 Flight 1: { CallSign:"AAL1001", DepartureAirport:"", ArrivalAirport:"KJFK",
 Stand:"G1", Runway:"04L", OffBlockTime:"10:00:00", TakeoffTime:"10:05:00",
 LandingTime:"", InBlockTime:"", AirlineName:"AAL",
 AircraftType:"A320", Airway:"", Registration:"N123AB",
 Voice:"en-US-1", Language:"en" }
 ... (10 flights, incrementing times, aircraft from the type pool, reg from registrationsByPair)
4. create_flights({flights: [f1, f2, ..., f10]})
 → If 422: read error.details, fix, retry
5. get_flights({airline:"AAL", type:"departure", limit:20}) → show user
6. get_validation_issues → report issues
7. Remind user: "10 flights created. Click Save when ready."

Example B: "Change all CCA flights to use runway 01"

1. get_editor_status
2. get_airport_info → check runwayStarCompat["01"]
3. modify_flights({match:{airline:"CCA"}, updates:{Runway:"01"}})
 → server cascades Airway to first valid STAR for runway 01
4. get_flights({airline:"CCA", limit:200}) → verify
5. Remind user to save

Example C: "Delete all JBU arrivals before 14:00"

1. get_editor_status
2. get_flights({airline:"JBU", type:"arrival", timeBefore:"14:00"})
 → show user, confirm
3. delete_flights({match:{callsigns:[...]}})
4. get_editor_status → confirm new count, remind to save

Chinese Examples (中文示例)

示例 D: "创建10个国航出发航班，10点开始每隔1分钟一个，机型随机"

1. get_editor_status → 确认已加载 level，currentAirport = "ZSJN"
2. get_airport_info → 获取约束：
 - airlineCode 包含 "CCA"
 - flightNumbers["CCA"] = ["1501", "1502", ...]
 - airlineAircraftCompat["CCA"] = ["A320", "B738", "B772"]
 - configTimeRange = { start: "06:00", end: "22:00" }
3. 构造10个完整 flight 对象：
 Flight 1: { CallSign:"CCA1501", DepartureAirport:"", ArrivalAirport:"ZSJN",
 Stand:"G1", Runway:"01", OffBlockTime:"10:00:00", TakeoffTime:"10:05:00",
 LandingTime:"", InBlockTime:"", AirlineName:"CCA",
 AircraftType:"A320", Airway:"", Registration:"B-1234",
 Voice:"zh-CN-1", Language:"zh" }
 ... (LLM 生成10个)
4. create_flights({flights: [f1, f2, ..., f10]})
5. get_flights({airline:"CCA", type:"departure", limit:20})
6. get_validation_issues
7. 提醒用户："已创建10个航班，请在编辑器中点击保存"

示例 E: "把所有国航航班改成01跑道"

1. get_editor_status
2. get_airport_info → runwayStarCompat["01"]
3. modify_flights({match:{airline:"CCA"}, updates:{Runway:"01"}})
4. get_flights({airline:"CCA"}) → 验证
5. 提醒保存

示例 F: "删除14:00前所有日航到达"

1. get_editor_status
2. get_flights({airline:"JAL", type:"arrival", timeBefore:"14:00"}) → 展示并确认
3. delete_flights({match:{callsigns:[...]}})
4. get_editor_status → 确认

9. Error Recovery

• get_editor_status returns editorReady: false → tell user to open a level in the editor first (use Chinese if the user is speaking Chinese)
• get_airport_info returns cacheReady: false → warn user the airport cache may not be ready
• create_flights or modify_flights returns 422 with error.details → read each detail, fix the specific fields, retry. Report the error in the user's language.
• Airport constraint maps are empty → validation is best-effort; warn user but proceed
• get_airport_info fails entirely → MCP cannot reach the editor; check npm start -- --api-port=31415
• User speaks Chinese but error uses English keys → translate field names for the user (e.g., "Stand 'G99' is not valid" → "停机位 'G99' 无效")
• User uses a Chinese airline name not in the mapping → resolve to a 3-letter code via the airline table in this skill (or AIRLINE_CODE_MAP in src/utils/constants/airlines.js); if unsure, ask the user for the 3-letter code. Note: constraints.flatLists.AirlineName is not populated — the name↔code mapping lives in the skill/constants, not in get_airport_info

10. Ground/Air Painter (unified)

Edit the level's static scenery (taxiways, runways, areas, stands) and airways (FIX waypoints + procedures) via the dedicated Ground/Air Painter window. The graph is id-free ({nodes, segments, runways, areas, stands, airwayNodes, procedures}); a meta side-table carries each object's original $k/OsmId/$id so survivors keep their ids at save. The mode toggle (ground ↔ air) is groundPainterMode in the store.

First turn on any ground/air task: get_editor_status → get_ground_painter_state.

10.1 Tool Coverage (mirrors the painter toolbar — ground + air)

Toolbar Tool	MCP Tool	Notes
Air/Ground view toggle (toolbar, right side)	`set_ground_painter_mode({mode:'ground'	'air'})`
Taxiway Line D (straight)	create_taxiway_lines({lines:[{a:{x,z}, b:{x,z}, name?, flags?}]})	Deduplicates nodes by coordinate (1e-6), validates distinct endpoints, pushes paired groundPainterHistory/groundPainterMetaHistory so undo restores correctly. flags defaults to 2 (wider).
Taxiway Curve / Fillet F (rounding)	create_taxiway_fillet({segA, segB, radius?})	Rounds the corner between two straight segments. segA/segB are segment indices (0..segments.length-1); radius 0.5..5.0 GU (default 2.0). Handles both connected (shared node) and virtual (disconnected) cases — virtual is additive (no deletions), connected truncates legs and inserts arc. Validates straight-only, angle 5..175°, parallel guard, degenerate-leg guard (collapsed leg/arc → rejected), pre-mutation same-anchor check, and ghost-ref repair.
Runway R	create_runways({runways:[{a:{x,z}, b:{x,z}}]})	Each runway is a runwayLine a→b pair. Names are derived from heading (e.g. 01/19) with suffix collision handling (L/R then C against taken physicalName/end names — avoids duplicate $k: runway:<name> → "found 0 named runways"), width 0.50, and a collinear pavement strip (Flags=4, name = physical name, 0.6 GU overhang) is auto-synthesized and coupled via meta.runwayPavement — same as GroundPainter.jsx:commitRunway. Returns created:[{names, physicalName}].
Area / Polygon G	`create_areas({areas:[{areaType:0	1
Stand H (plane)	create_stands({stands:[{x,z, heading:1..360}]})	Nose-anchored; creates nose+tail nodes (STAND_LENGTH=0.63) and a heading in 1..360 (0/unset → 360/north via _normalizeHeading). Mirrors GroundPainter.jsx:standHeadingPlacement.
Airway Node N (air)	create_airway_nodes({nodes:[{x,z, name?}]})	Air FIX waypoint. Creates a new airway node per entry; optional name defaults to FIX<n>; validates finite x/z; pushes paired history (meta airwayNodeOrigPk + null).
Airway Procedure C (air)	create_airway_procedures({procedures:[{name, routeType:0..3, runwayName, airwayNodeIdxs:[≥2]}]})	Chains existing airway nodes into a procedure (STAR 0 / APP 1 / SID 2 / MISS 3). Validates runway exists, idx range, no consecutive dup, duplicate (name,runway,routeType) rejected. Pushes paired history (meta airwaySegOrigPk).
Air Fillet F (air)	create_airway_fillet({procedure, vertex?, radius?})	Intra-procedure fillet (AAA): rounds an interior corner of ONE procedure. Pass {procedure, vertex} (vertex = position of the corner fix in airwayNodeIdxs, 1..len-2) or omit vertex to auto-pick the sharpest filletable corner. radius is 50..500 GU (default 120; clamped down to the leg length). Connected-only (no virtual); validates angle 5..175°, parallel guard; replaces the corner fix with T1 + arc-interior + T2 nameless nodes and reroutes airwayNodeIdxs. Inter-procedure (procA != procB) is rejected — matching the UI, where after picking an edge of AAA the snap/select is locked to AAA.
Select / Box Select	get_ground_painter_state + delete_ground_objects/delete_airway_objects	Selection itself is UI-only; MCP reads the graph via get_ground_painter_state and deletes via point query (see below).
Delete (single ground)	delete_ground_objects({target:{x,z}, threshold?})	Deletes the nearest ground object to target using the same priority as the UI Select tool: stand > segment/runway > area (SKILL.md: pickForeground). threshold defaults to 0.6 GU. For runways cascades to strips + threshold nodes; records meta.deletedPks/deletedAreaIds/deletedStandNames/deletedRunwayNames and does orphan-node GC so the delete persists through patchSceneryBlob; pushes paired history.
Delete (single air)	delete_airway_objects({target:{x,z}, threshold?})	Deletes the nearest air object to target (airwayNode > procedure priority, threshold 0.6 GU). Node delete cascades to degenerate procedures (<2 nodes); records meta.deletedAirwayPks / airwayNodeOrigPk/airwaySegOrigPk GC so save persists; pushes paired history.
Move objects (ground)	move_ground_objects({targets:[{x,z}×≥1] OR selectAll:true, dx, dz, threshold?})	Translate 1..N ground objects (mirrors Select body-drag: single/multi/selectAll). Targets resolve like delete (ground). Runway moves carry coupled pavement strips; areas translate polygon points. Pushes paired history.
Move objects (air)	move_airway_objects({targets:[{x,z}×≥1] OR selectAll:true, dx, dz, threshold?})	Translate 1..N air objects (airway node / procedure body). Targets resolve like delete_airway; a procedure move carries its member nodes; selectAll moves every airway node. Pushes paired history.
Move endpoint/vertex	`move_ground_endpoint({target:{x,z}, to:{x,z}, kind:'node'	'areaVertex'})`
Rename (ground)	`rename_ground_object({kind:'segment'	'runway'
Rename (air)	`rename_airway_object({kind:'airwayNode'	'procedure', idx, name})`
Undo	undo_ground_painter({})	Depth-1 undo — restores both groundPainterGraph and groundPainterMeta (paired groundPainterHistory/groundPainterMetaHistory), matching the UI's Ctrl+Z (appStore.js:setGroundPainterGraphWithMeta). Returns {undone:true/false}.

10.2 State

• get_ground_painter_state → { graph, summary, metaSummary, tool, mode, isOpen, hasEdited, historyDepth }. summary: {nodes, segments, runways, areas, stands, airwayNodes, procedures}; metaSummary: {nodeOrigPk, segOrigPk, deletedPks, deletedAreaIds, deletedStandNames, deletedRunwayNames, runwayPavement, runwayOrigInfo, airwayNodeOrigPk, airwaySegOrigPk, deletedAirwayPks} (for write-path debugging). mode: ground|air. If graph is null the painter is not seeded — open the Ground Painter UI once; the MCP now returns a friendly {success:false, error:'Ground Painter not yet initialized — open the Ground Painter UI once…'} instead of a raw -32603.

10.3 Lifecycle & Guarantees

• Paired history: every mutating MCP tool (create_*, create_runways, create_taxiway_fillet, create_airway_*, delete_*, move_*, rename_*) pushes groundPainterHistory and groundPainterMetaHistory via _pushPainterHistory before mutating, so undo_ground_painter restores a consistent pair (no meta-graph drift).
• Meta persistence: creates push null into nodeOrigPk/segOrigPk/runwayOrigPk/areaOrigId/standOrigPk/airwayNodeOrigPk/airwaySegOrigPk for new objects; deletes push the survivor's PK/id into deletedPks/deletedAreaIds/deletedAirwayPks and run orphan-node GC (adjusting runwayPavement indices), so patchSceneryBlob drops them at save — including jetway cascade (_reconcileJetwayFrames) for deleted stands and checkpoint-frame reconciliation for runways (_reconcilePhysicalRunwayFrames) + airway dangling gate for airway-node.
• Node dedup: create_taxiway_lines reuses an existing node when a coordinate matches within 1e-6 (_findNodeIndexByCoord), preserving shared junctions; create_stands/create_runways/create_airway_nodes create fresh nodes for their geometry (airway nodes are always new, never deduped).
• Validation: distinct-endpoint checks (Segment needs distinct endpoints), area ≥3 vertices, areaType 0|1|2, runway distinct endpoints, fillet straight-only + angle/parallel/radius guards, airway idx range + duplicate (name,runway,routeType), segment/procedure-index range checks, and target type checks all return {success:false, error} with isError:true (no raw throw).
• In-memory until Save: all edits are in-memory until the painter's Save (confirm prompt with .bak checkbox) — or Cancel which discards. The painter renders as a full-screen fixed overlay (z-index:9999) that visually covers the editor; the MCP API is not gated — create_flights/modify_flights still run while the painter is open. A 0-runway graph cannot be saved: the painter save() blocks with ground_painter_validation_runway_required, and the save-ground-painter-data handler refuses the write (0 runway: static keys) because the game throws ArgumentException: runway.initialRunways is empty. A runway created via create_runways is auto-added to the level's InitialRunways (its primary end), so a fresh runway is active on load.
• Flight reconciliation: after the scenery write, save-ground-painter-data compares the saved file's stands/runways against the pre-save snapshot, remaps renamed runway ends/stand identifiers (index-parallel runwayOrigInfo/runwayOrigPk + nose-position matching, existence-guarded), purges flights whose Stand/Runway no longer resolves, rebuilds flight sections via generateFullAcl + CSV sync, and returns purgedFlights/refsRemapped (the renderer's snapshot is refreshed from readAclText when flight sections were rebuilt).
• Degenerate-edge guards: node drags freeze when consecutive vertices would colocate; attachVirtualFilletLeg/applyVirtualFillet reject collapsed legs/arcs and same-anchor fillets before mutating; create_areas and area vertex drags reject bowtie polygons via polygonIsSimple (src/acl/scenery_graph.js + ESM mirror polygon_simple.js); air fillet rejects non-connected (virtual) pairs.
• Runway designation dedup: create_runways suffix-deduplicates heading-derived names (L/R then C) so two runways never share a $k: runway:<name> key.
• Jetway & airway integrity: stand deletes via delete_ground_objects record PKs, so the save drops jetway:* static items and their checkpoint jetway:* runtime entities — no more Jetway: static item 'jetway:NN' does not exist at level init. Airway node deletes cascade to degenerate procedures (<2 nodes) and are guarded by the airway dangling gate (airway-node → airway-segment/runway Routes), so no stray $iref to a deleted FIX survives.