mcpbeat

Iwsdk Planner

facebook/iwsdk-planner

IWSDK experience pipeline and planning guide. Use when building a new IWSDK app/game end-to-end, planning new IWSDK features, designing systems/components, reviewing IWSDK code architecture, or when the user asks about IWSDK patterns, ECS design, signals, or reactive programming. Runs a phased ideation → design → grounding → architecture → build → verify → ship pipeline, orchestrating sub-agents per phase where the harness supports them.

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on the repository, not the skill itself

Install

one command, takes just this skill from the repository
npx skills add https://github.com/facebook/immersive-web-sdk --skill iwsdk-planner

What comes with it

99 788 bytes besides the instruction
references/api-reference.md
references/build-milestones.md
references/design-deck.md
references/grounding.md
references/ideation.md
references/verification.md

What it tells the agent to use

found in the instruction text
Grep reads your files
Task spawns other agents

The instruction itself

15 sections, as written by the author

IWSDK Experience Pipeline

You are an expert IWSDK (Immersive Web SDK) architect and producer. This skill

turns an idea ("a VR bowling game", "an AR plant identifier") into a specced,

designed, grounded, built, and verified IWSDK app through explicit phases —

each phase producing reviewable artifacts on disk before the next begins.

Choose Your Mode

| Situation | Mode |

| ---------------------------------------------------------------------------- | --------------------------------------------------------------------- |

| New experience/game/app from an idea, or a large feature epic (multi-system) | PIPELINE — run the phases below |

| Small feature in an existing app, an architecture question, a code review | QUICK — jump to Quick Planning |

When in doubt: if the work needs a spec the user should react to, use PIPELINE.

Operating Principles

  • Artifacts over conversation. Every phase writes files under design/

in the project. Files are the source of truth; the conversation is not.

Anyone (including a fresh agent) must be able to resume from disk alone.

  • Phase gates. Do not start phase N+1 until phase N's artifact exists and

its gate is satisfied. Record progress in design/PIPELINE.md (template

below). Skipping a phase is allowed only if the user asks for it — record

the skip and why.

  • Sub-agents where available, inline where not. If your harness has a

sub-agent/Task tool, fan phases out as described in each phase's playbook —

parallel agents for independent artifacts, one agent per research domain,

disjoint file ownership for build agents. If not, do the same steps

yourself, sequentially. The artifacts and gates are identical either way.

  • The developer is a collaborator, not an oracle. Ask real questions at

ideation and at gates (use a structured question tool such as

AskUserQuestion when available — batched, with opinionated defaults). If

the user is absent or asked you to proceed autonomously, choose defaults

and mark every such decision [ASSUMED] in the artifact, then continue.

  • Ground before you build. No implementation before every mechanic in the

spec is mapped to IWSDK built-ins or explicitly classified as custom work

(Phase 3). Rebuilding something IWSDK provides is the #1 failure mode.

  • Verify with the runtime, not vibes. "It compiles" is not a gate.

Milestones pass only when the live app (dev server + emulated XR input +

ECS assertions + screenshots) demonstrates the behavior.

Pipeline State File

Create design/PIPELINE.md at the start; update it at every phase boundary:

# <Project Name> — Pipeline State

| Phase          | Status      | Artifact                          | Notes                          |
| -------------- | ----------- | --------------------------------- | ------------------------------ |
| 0 Preflight    | done        | (this file, Capabilities below)   |                                |
| 1 Ideation     | done        | design/GAME_SPEC.md               | approved by user / assumptions |
| 2 Design       | in-progress | design/deck.html, design/concept/ |                                |
| 3 Grounding    | pending     | design/TECH_PLAN.md               |                                |
| 4 Architecture | pending     | design/ARCHITECTURE.md            |                                |
| 5 Build        | pending     | src/, milestone log below         |                                |
| 6 Verify       | pending     | design/VERIFICATION.md            |                                |
| 7 Ship         | pending     | review report, build, deploy      |                                |

## Capabilities (Phase 0 findings)

- interactive questions: yes (AskUserQuestion) | no (autonomous)
- sub-agents: yes (Task tool) | no
- slide/HTML preview: artifact tool | file only
- image generation: <tool name> | none (SVG fallback)
- iwsdk CLI: <version> | pending scaffold · reference: ready|warmup-needed|unavailable
- runtime verify: managed headed browser ready | blocked because <why>

## Milestone Log

- M0 <date>: scaffold renders — screenshot design/verify/m0.png

Resuming: if design/PIPELINE.md exists, read it plus the artifacts of

completed phases, then continue from the first non-done phase. Never redo a

done phase unless the user changes the requirements behind it.


Phase 0 — Preflight (capability & environment probe)

Goal: know what this harness and machine can do, so later phases degrade

gracefully instead of failing mid-flight.

Probe and record in design/PIPELINE.md (Capabilities section):

  • Interaction — can you ask the user structured questions and get answers

(e.g. AskUserQuestion tool)? If the user said "build it, don't ask me", or

no question tool exists and the user is unresponsive, set autonomous.

  • Sub-agents — do you have a Task/agent-spawning tool? Note limits you

know (e.g. sub-agents usually cannot keep background processes alive — the

main agent must own dev servers).

  • Presentation — can you render/publish HTML (artifact tool)? Can you

generate images (any image-gen tool)? Fallback: hand-authored SVG + local

HTML files.

  • Toolchainnode --version (needs >=20.19 <21, >=22.12 <23, or >=24);

is there an existing IWSDK app here or are we scaffolding fresh?

  • IWSDK tooling — only if an app already exists, and always from its

directory (never a bare shell/monorepo root — npx iwsdk outside an app

resolves to an unrelated npm package): npx iwsdk status,

npx iwsdk reference status. Fresh installed scaffolds initialize this

shared cache during creation. If an older/existing app still reports warmup

needed and you have network, start npx iwsdk reference warmup **in the

background now** (~210 MB download) so it's ready by Phase 3. If it fails, note the

docs fallback (see references/grounding.md). Scaffolding fresh?

Skip these probes, record iwsdk CLI: pending scaffold, and rely on the

Scaffold Checkpoint below to run them right after ideation.

Gate: Capabilities section filled in. This phase never asks the user anything.

Phase 1 — Ideation (idea → spec)

Goal: lock the idea into design/GAME_SPEC.md — the single document that says

what we are building, for whom, on what device, at what scope.

Playbook: references/ideation.md (question bank, spec template, worked

example).

Procedure:

  • Restate the user's idea in 2–3 sentences. State the genre, the fantasy,

and the obvious open questions.

  • Ask batched question rounds (3–4 questions each, each with 2–4

opinionated options + your recommended default; structured question tools

typically cap a call at 4 questions — split a bigger round into two

calls rather than dropping questions). Round 1: platform & mode

(VR/AR/browser-first/dual), core loop, scale/comfort. Round 2: mechanics

detail, art/audio direction, scope tier. Stop when the axes in the

template are pinned — usually 2 rounds, 3 max. In autonomous mode:

answer every question yourself with the most defensible default, mark

[ASSUMED], and keep a "Questions I would have asked" appendix.

  • Write design/GAME_SPEC.md from the template: pitch, pillars, core loop,

mechanics list, platform/mode, space & locomotion needs, UI surfaces,

audio moments, art direction, scope tiers (MVP / target / stretch),

non-goals, success criteria (each criterion must be _observable_ — you

will assert it in Phase 6).

  • Present a compact summary and get sign-off (or record [ASSUMED] set).

Gate: spec exists; every mechanic is named; success criteria observable;

user approved or assumptions documented.

Scaffold Checkpoint (fresh projects only)

Ideation locks the platform axes — scaffold now, before Phase 2, so the

project directory exists for every later artifact and tool:

  • Scaffold with @iwsdk/create using the spec's mode/features

(references/build-milestones.md has the flag menu); cd into the app.

  • Move any design/ files created so far into <app>/design/ — from here

on, everything lives in the app root. Do the move BEFORE fanning out

Phase 2/3 agents (or brief them with the final app paths) — agents

writing to a stale staging path while you move it lose work.

  • Run the deferred Phase 0 probes (npx iwsdk status, `npx iwsdk reference

status`). Creation initializes the reference cache before returning. Only if

status still reports warmup required should you run `npx iwsdk reference

warmup` and treat a failure as a scaffold/setup defect.

  • Do not modify app code yet — Phase 5's M0 verifies the untouched

scaffold. Never scaffold a nested app inside an existing IWSDK app.

Phase 2 — Design (spec → deck + concept art)

Goal: make the spec _visible_ so the developer can react to a look and a

layout, not a wall of text. Everything here is presentational — no code.

Playbook: references/design-deck.md (deck outline, HTML/SVG conventions,

concept-art briefs, capability ladder).

Fan out (parallel sub-agents if available, else sequential):

  • Deck agentdesign/deck.html: self-contained slide deck (inline CSS,

arrow-key navigation) covering pitch, pillars, core loop diagram, mechanics,

level layout, interaction model, art/audio direction, scope, tech snapshot.

  • Concept-art agentdesign/concept/*.svg: 2–4 hand-authored SVG

pieces (key moment, environment mood, UI mock). Use an image-generation

tool instead if Phase 0 found one.

  • Layout agentdesign/concept/layout.svg: top-down play-space diagram

with dimensions in meters (XR scale is real scale — a desk is 0.75 m high).

Each agent reads design/GAME_SPEC.md; give them the file path, not a paste.

Present results (artifact tool if available, else file paths + one-line

descriptions). Ask for reactions if interactive; else proceed.

Gate: deck + at least one concept piece exist and match the spec.

Phases 2 and 3 both consume only the spec. They may run concurrently only

when npx iwsdk reference status already reports ready. Otherwise, let Phase 2

run while warmup finishes, then confirm readiness (or select the documented

fallback) before launching Phase 3. Both phases must be done before Phase 4.

Phase 3 — Grounding (spec → IWSDK reality)

Goal: design/TECH_PLAN.md — every mechanic mapped to concrete IWSDK API

surface, so Phase 5 is assembly rather than discovery.

Playbook: references/grounding.md (reference CLI protocol, docs fallback

ladder, domain→API map, TECH_PLAN template). API ground truth:

references/api-reference.md.

Procedure:

  • Enforce the reference barrier: confirm npx iwsdk reference status is

ready, or record which fallback from references/grounding.md will supply

API evidence. Never fan out grounding agents while warmup is still running.

  • Derive research domains from the spec (typically: input & interaction,

physics, locomotion, UI, audio, environment/lighting, assets/levels, and

AR-specific surfaces if applicable).

  • Fan out one research agent per domain (or do them in sequence). Each

agent: reads the spec + references/grounding.md, queries the reference

system (npx iwsdk reference search|api|components|systems|examples) or

the documented fallbacks, and returns table rows:

`mechanic → classification (BUILT-IN | CONFIGURE | CUSTOM) → exact IWSDK

pieces (components/systems/feature flags) → custom work remaining → risks`.

  • Merge into design/TECH_PLAN.md: iwsdk.config.json world/feature block,

the mechanics table, custom system specs (queries, priorities, globals),

asset manifest (see Asset Strategy in references/build-milestones.md),

and a risk list with mitigations.

  • Audit against the reinvention-risk table in references/api-reference.md:

anything classified CUSTOM that IWSDK already provides gets reclassified.

Gate: no mechanic left unclassified; feature flags decided with prerequisites

checked (e.g. locomotion requires collision geometry); every CUSTOM item has

a sketched query/system design; asset list complete.

Phase 4 — Architecture (tech plan → build plan)

Goal: design/ARCHITECTURE.md — the file-by-file, milestone-by-milestone

construction plan.

Playbook: references/build-milestones.md (template, scaffold flags,

milestone rules, sub-agent file-ownership rules).

Contents: scaffold command (exact @iwsdk/create flags) or existing-app

delta; file tree (one system per file); component schemas (names, fields,

Types); systems table (name, queries, priority band: 0–9 input / 10–19 sim /

20–29 visual sync / 30+ UI); globals signals; milestone plan — M0 "scaffold

renders" through M-final, each with a demo criterion (what you can see)

and assertions (what you will check via the CLI in Phase 6).

Gate: every spec mechanic traces to a milestone; every milestone has demo

criterion + assertions; user approved (or [ASSUMED]).

Phase 5 — Build (milestone loop)

Goal: working code, one verified milestone at a time.

Playbook: references/build-milestones.md. API ground truth while coding:

references/api-reference.md — follow its best practices (stateless systems,

signals, cleanup, createTransformEntity, AssetManager, feature-flag

hygiene) and its anti-pattern list.

Rules:

  • M0 baseline first: the app scaffolded at the Scaffold Checkpoint — or,

when already inside a generated/existing IWSDK app (the common case for

this skill), that app adopted as-is ("existing-app delta" in

references/build-milestones.md; never scaffold a nested app). Run the

verify loop once end-to-end (dev server up, screenshot, XR enter) _before_

writing gameplay code. A broken baseline poisons every later diagnosis.

  • The main agent owns the dev server and everything stateful (`iwsdk dev

up/down, ports, browser). Sub-agents write code; they may run npx tsc

--noEmit` but must not start servers.

  • Parallel sub-agents only for genuinely independent modules, each owning a

disjoint set of files; the main agent owns shared files (src/index.ts,

component registry wiring) and integrates.

  • After each milestone: npx tsc --noEmit → verify loop (Phase 6 subset for

this milestone's assertions) → update Milestone Log in design/PIPELINE.md

(+ commit — confirm once at Phase 5 start, or [ASSUMED] in autonomous

mode; see references/build-milestones.md).

  • When something fails, debug with the runtime tools (ecs pause/step/

snapshot/diff, browser logs), not by staring at code — see

references/verification.md.

Gate (per milestone): demo criterion observed + assertions pass + typecheck

clean.

Phase 6 — Verify (whole-app pass)

Goal: design/VERIFICATION.md — evidence, per success criterion from the

spec, that the app does what the spec says.

Playbook: references/verification.md (the exact CLI loop, input-simulation

cheat sheet, assertion patterns, known traps, recovery ladder).

Run the full loop against the finished app: typecheck → dev up → connectivity

→ browser screenshot → XR enter → clean console → per-criterion scenario

(simulate inputs, assert via ecs query/snapshot/diff/screenshots/log

patterns). Record each criterion PASS/FAIL with the evidence (command +

output + screenshot path). Fix and re-run failures; a criterion the runtime

cannot demonstrate goes back to Phase 5, or gets renegotiated with the user.

Autonomous mode: after 2–3 focused fix cycles on a stubborn criterion, stop

looping — record it as FAIL under "Deferred / known gaps" in

design/VERIFICATION.md with the attempted evidence, mark the spec item

[FAILED — deferred], and proceed to Phase 7 with the failure stated

prominently in the close-out report.

Gate: all MVP success criteria PASS with recorded evidence — or each failure

explicitly deferred with evidence of the attempts (autonomous mode).

Phase 7 — Review & Ship

  • Review — run the iwsdk-project-code-reviewer agent (ships with IWSDK

projects) over the code; apply Critical/Warning fixes; re-run the Phase 6

assertions touched by the fixes. No agent tool, or the agent file missing?

Review the diff yourself against references/api-reference.md — the

Anti-Patterns list, the reinvention-risk table, and the Performance

Tips — and record findings in the close-out report.

  • Performance sanity — VR frame budget is 11–14 ms: check for per-frame

allocations, unthrottled queries, oversized textures (the reviewer flags

most of these).

  • Buildnpm run build; confirm dist/ contains the changes

(grep a distinctive pattern in dist/assets/*.js).

  • Ship — per user preference: static deploy of dist/ (e.g.

npx gh-pages -d dist), zip delivery, or just the local build

(autonomous default: local build only; list deploy options in the

close-out report).

  • Close out — final report: what was built vs the spec (including every

[ASSUMED] decision), evidence summary, known gaps / stretch items, and a

short retro (what to do differently next time) appended to

design/PIPELINE.md.


Quick Planning (single features)

For a contained feature in an existing app, skip the pipeline and run this

checklist (details in references/api-reference.md):

  • Feature flags — what built-ins does this need (locomotion, physics,

grabbing, spatialUI, sceneUnderstanding…) and are their prerequisites met

(e.g. locomotion needs collision geometry)?

  • Check the reinvention-risk table — is this already a built-in?
  • Ground itnpx iwsdk reference search/api/examples for the pieces

you'll touch (protocol in references/grounding.md).

  • Components — what data, what Types, tag vs data components?
  • Queries & reactivity — how do systems find entities; qualify/

disqualify subscriptions over polling; signals for state.

  • Lifecycle — who creates/destroys entities; destroy() vs dispose();

level persistence.

  • Priority band — 0–9 input, 10–19 sim, 20–29 visual sync, 30+ UI.
  • VR vs AR vs browser — behavior per mode; input per mode.
  • Audio & feedback — what plays on which interaction.

10. Assets — Asset Strategy in references/build-milestones.md.

11. Verify plan — which CLI assertions will prove it works

(references/verification.md).

Then implement following the best practices and verify with the runtime loop.

Reference Files

| File | Load when |

| -------------------------------- | ----------------------------------------------------------------------------------------------- |

| references/api-reference.md | grounding, coding, reviewing — the API ground truth |

| references/ideation.md | Phase 1 — question bank + GAME_SPEC template |

| references/design-deck.md | Phase 2 — deck/concept-art briefs + templates |

| references/grounding.md | Phase 3 / Quick step 3 — reference CLI + fallbacks + TECH_PLAN template |

| references/build-milestones.md | Phases 4–5 — scaffold flags, architecture template, milestone & sub-agent rules, asset strategy |

| references/verification.md | Phases 5–7 — runtime verify loop, input simulation, traps |

How to use it

Copy the folder

Take facebook/iwsdk-planner from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.

Install what it needs

The instructions reference npx. Without those the skill loads but fails at the first command.