canvas-app

Create or Edit a Canvas App

Create or edit a Power Apps canvas app for:

$ARGUMENTS

Establish the Workspace

Canvas Authoring tools operate on a local directory containing the app YAML.

1. Treat ${PLUGIN_ROOT} as immutable runtime provenance. Never derive it from the current directory, app workspace, repository root, or a sibling worktree.
2. Read ${PLUGIN_ROOT}/references/QAChecks.md and require QACHK-SHARED-SOURCE-DERIVATION. If the check fails, stop with the observed path; do not mix prompt generations.
3. Reuse the current directory when it already contains App.pa.yaml and every existing file in that directory is a .pa.yaml file.
4. Otherwise, reuse the single immediate child directory containing App.pa.yaml, when exactly one exists and every existing file in it is a .pa.yaml file.
5. Otherwise, derive a short kebab-case folder name from the app name or requirements, create a new empty directory with Bash, and resolve its absolute path. If that name already exists and contains non-YAML files, choose a fresh suffixed name rather than synchronizing into it.
6. Call sync_canvas with that absolute working directory before reading or editing app files. The directory must be dedicated to this app and contain no non-.pa.yaml files when synchronization starts; never pass the repository root or ${PLUGIN_ROOT}. Do not call sync_canvas against the working directory again after planning or acceptance documents have been created there. Do not proceed if the initial sync fails.

Always use absolute paths for app files.

Route the Request

Inspect the synced .pa.yaml files before choosing a workflow. A blank app normally contains App.pa.yaml, Screen1.pa.yaml, and _EditorState.pa.yaml.

Treat the app as empty when it has no screens with meaningful leaf controls. Containers without leaf controls do not make the app non-empty.

• Empty app: read ${PLUGIN_ROOT}/references/CreateWorkflow.md and follow it.
• Existing app: read ${PLUGIN_ROOT}/references/EditWorkflow.md and follow it.

Do not load both workflow documents.

Planned Build Handoff

CREATE and complex EDIT workflows return here after the planner finishes.

1. Read the orchestrator-authored [working directory]/canvas-app-requirements.md and [working directory]/canvas-app-plan.md returned by the planner. The requirements artifact must already exist before planner delegation, use contract version 1, preserve the original request, identify the target device, and assign stable requirement, action, scenario, and specialized-contract mappings. Do not let the planner create, rewrite, or replace this upstream artifact.
2. Verify ## Original Request Capability Inventory was captured from the original request before planner reduction. Every stable key must appear in ## Requirement Coverage and map to existing Action Contract key(s), named observer(s), and Functional Test Matrix scenario key(s). Reject dropped clauses and unknown mappings; do not add universal CRUD absent from the request.
3. Verify its ## Requirement Coverage table maps every concrete requested noun and interaction to a visible affordance. Any approximation must be explicit and must not use UI copy that claims the unavailable interaction is exact.
4. When the app contains record cards, rows, lists, or details, verify its ## Required Record Fields table has one stable key for the canonical identity and every field the requirements say users must see. Reject a time-only, identity-only, or action-only surface when additional title, person, time, description, status, or other values are requested.
5. Verify its ## Action Contracts table:
   • Every requested or approved action has its own row and reachable entry point.
   • Create, edit, delete, search, filter, approve, reject, period, and export behaviors are not collapsed into vague combined rows.
   • When review distinguishes approved and rejected outcomes, Approve and Reject/Decline have separate contracts owned by the same eligible record surface.
   • Opposing transitions such as Receive/Issue, Increase/Decrease, Credit/Debit, Allocate/Release, Check-in/Check-out, and Enable/Disable have separate contracts even when one shared form implements both.
   • When opposing actions use a shared-operation flow — directional selector events commit operation state and a distinct guarded event consumes that state to mutate — each selector is selection-only and that distinct event is the single mutation entry point, regardless of control name or label. Both contracts name that same mutation event and operation state. A selector that calls Patch, SubmitForm, Collect, Remove, RemoveIf, UpdateIf, or a connector mutation is invalid. Separate direct-action controls remain valid when no distinct shared mutation event exists and each action has its own selected-ID and amount eligibility gates. Their control identity commits direction, so they need no shared operation variable/reset.
   • Every mutation names an observable bound result, not only a confirmation message.
   • Every mutation declares a write set and receipt proof set. For create/edit, reject the plan when any user-entered or user-selected write-set field is absent from the proof set.
   • Every mutation has an additive lifecycle row naming its receipt, canonical source, requested destination, same stable ID, and exact synchronization/focus behavior when the destination differs or contains multiple records.
   • Every mutation has a Changed/Preserved field ledger. Changed rows match handler writes and receipt proofs one-for-one; Preserved rows retain canonical pre-state and name post-state evidence.
   • Conditional stable-ID continuation exists only when create feeds a later edit, delete, relationship, approval, or transition. It binds that action to the returned create ID and clears continuation state on downstream completion or cancellation.
   • Every plan-declared state-driven UI surface names the surface control and its exact state predicate. Recognize either the dedicated table or an exact Surface.Visible=state predicate Action Contract observer. Do not add rows for always-visible surfaces, child-only visibility, navigation-based disclosure, or visibility not declared by the plan.
   • Supporting setup actions exist when required to exercise an explicitly requested lifecycle, relationship, comparison, or ranking.
   • Role-scoped management of all primary records includes separate visible select/edit/save and remove/cancel paths, not only review or status controls.
   • Create/edit contracts define required inputs, directly selectable finite choices, stable identity, edit prepopulation, cancel/reset behavior, and post-save evidence.
   • Every row names a precondition, source and stable identity, exact transition and postcondition, observer reading that source, and visible evidence.
6. Verify its ## Functional Test Matrix:
   • Every Action Contract has at least one deterministic Given/When/Then success row.
   • Every required invalid, blocked, empty, clear/reset, or boundary path has a row.
   • Every direction of an opposing pair has its own concrete scenario with explicit old value/state, selected operation, amount when applicable, and expected new value/state.
   • Every Then names a source postcondition and an evidence surface that reads it.
   • Local/mock scenarios use concrete seeded IDs and values. Filter scenarios include at least two matching records and one non-matching record.
   • EDIT scenarios cover existing behavior touched by changed sources, fields, controls, or observer formulas.
   • When a continuation contract is present, scenarios cover the returned-ID-bound downstream completion and non-mutating cancellation paths, including continuation-state clear.
7. When the plan contains an opposing directional pair, require ## Directional Mutation Evidence before dispatch. It must state a nullable selected-ID state with blank reset and row assignment, the actual operation state with an entry/success Blank() reset event, representable blank/non-positive amount bindings, a disabled invalid submission gate, exact final formulas for both directions, a canonical-source observer, and receipt bindings for operation, old value, amount, expected value, and actual persisted value. For a shared-operation flow, the plan must also identify each selection-only binding, the common guarded mutation event, and their common operation state.
8. Verify every responsive or unknown-device screen has a ## Viewport Containment Contracts row naming one sole top-level AutoLayout root with exact Width: =Parent.Width and Height: =Parent.Height. All visible and conditional surfaces must be nested below it.
9. When requested behavior orders or compares time-of-day values, require ## Temporal Ordering Contracts. Sort typed Date/Time fields directly, or require validated input normalization to a zero-padded 24-hour HH:mm sort key with explicit invalid/blank behavior. Reject direct sorting of 12-hour, non-padded, or mixed display strings.
10. Verify its ## Dispatch table:
    • Every row has Action, Screen, Target File, YAML Key, Name Prefix, and Screen Brief.
    • CREATE rows use Create; EDIT rows use Modify or Create.
    • Target files and screen briefs are absolute paths under [working directory].
    • No two rows target the same file.
    • No two rows share a Name Prefix.
    • In CREATE mode the first row targets [working directory]/Screen1.pa.yaml with YAML key Screen1.
    • ## Editor State Changes exists and contains exact final order lists or None.
11. Confirm [working directory]/canvas-app-shared.md and every dispatch row's Screen Brief exists. Verify each brief's assignment matches its dispatch row and includes every Action Contract owned by that screen under ## Required Actions and every scenario it exercises under ## Functional Test Scenarios. It also includes every ## Required Record Fields row owned by that screen with an exact bound control, formula, hierarchy, visibility rule, and layout budget.
12. Before dispatch, read every brief and reject it when:
    • a used control lacks its exact creation keywords, supported input-property names, or the full Enum name: and compile-ready enum literal required by discovery;
    • a Required Action is only an identifier or summary instead of its complete precondition, event, source/stable identity, postcondition, observer, and evidence;
    • a Functional Test Scenario is only an identifier instead of complete Given/When/Then text, boundary conditions, and expected evidence; or
    • it contains an unresolved placeholder or delegates discovery to the builder.
13. In EDIT mode, apply the ### Before builders group of ## App Changes to [working directory]/App.pa.yaml now. Screens bind to those collections, formulas and variables, and compiling them against a stale App.pa.yaml produces a flood of false name errors.
14. Call compile_canvas now and resolve every App-level diagnostic before dispatching. The planner cannot validate through the top-level MCP connection. For EDIT mode, compile after applying the before-builder app changes and resolve App-level diagnostics before dispatching.
15. Invoke one general-purpose agent with Task per dispatch row and instruct it to read and follow ${PLUGIN_ROOT}/agents/canvas-screen-builder.md using the supplied assignment. Run these workers in waves of at most three. Fire each wave together, wait for it to return, then dispatch the next.

Never dispatch more than three builders at once. Larger fan-outs have hung without returning, and waves of three get you the first compile sooner, which is where systemic defects surface.

If any pre-dispatch check fails, do not start builders. Re-invoke the planner with the specific defects and repeat the checks on the corrected artifacts.

If the planner reports that writing is unavailable or denied, or returns without the required artifacts for that reason, write the planner's complete inline artifact payloads verbatim with apply_patch; do not redesign or rediscover them. If any payload is absent or cannot be written, stop and report the tooling failure. If the planner returns Status: Provenance Blocked, stop without a fallback; mixed prompt generations cannot produce trustworthy artifacts.

Pass each builder only:

Action: [Create / Modify]
Screen: [logical screen name]
Target file: `[working directory]/[file].pa.yaml`
YAML screen key: [key from dispatch row]
Control name prefix: [prefix from dispatch row]
Shared plan: `[working directory]/canvas-app-shared.md`
Screen brief: `[working directory]/[file-base].screen-plan.md`
Plugin root: ${PLUGIN_ROOT}

The target file, YAML key, and name prefix are authoritative. Modify actions preserve the key already present in the target file.

Compile after each wave returns, before dispatching the next. A systemic mistake in the first wave is usually repeated in every later screen. Repair files that already exist in place; only rows still waiting for dispatch receive corrected briefs.

A between-wave compile can report a Navigate target that belongs to a later wave as unrecognized. Confirm it matches a remaining dispatch row and leave it in place.

After all builders finish:

• Confirm every dispatched builder and every targeted self-QA follow-up has returned before final validation begins. Do not leave a worker running or queued that can write after the final compile.
• Treat final validation as a one-way barrier. Before crossing it, finish every Task, read_agent, builder repair, QA follow-up, inspection, and evidence update that could require another workspace change. Once final validation begins, do not launch or resume an agent.
• Check each builder's Functional: section before accepting its QA report. It must contain exactly one PASS trace per Required Action in that screen's brief, and each trace must name the precondition, control event, source/stable-ID operation, postcondition, and observer/evidence. A missing link, generic claim, or BLOCKED result sends that screen back for targeted repair and a corrected trace; do not accept checklist PASS as a substitute.
• Check each builder's QA coverage, repairs, and N/A lines. Treat these as unrun and send the screen back for self-QA only — not a rebuild — before you compile:
  • missing QA coverage: 1-44 COMPLETE, repair, or N/A lines;
  • any legacy QA: 1 PASS checklist or repair entry that does not use a defined QACHK-* identifier followed by FIXED(n);
  • an outcome that contradicts the screen structure — for example, QACHK-CROSS-AXIS-ALIGNMENT is N/A despite AutoLayout children, QACHK-ACCESSIBLE-LABEL-MISSING is N/A despite content or input controls, QACHK-LOW-CONTRAST-TEXT is N/A despite a non-default coloured surface, or QACHK-ROOT-CONTAINMENT is PASS while a responsive root has screen-level siblings;
  • QACHK-GALLERY-ROW-FITS-CONTENT is N/A despite the screen containing a Gallery;
  • QACHK-ACTION-LABEL-FIT is PASS while a multiword action directly under vertical AutoLayout lacks Width: =Parent.Width; PASS is valid after a complete inspection finds no defect; never reject it solely because the screen has many controls. For QACHK-NO-HEIGHT-TRAP, QACHK-GALLERY-ROW-FITS-CONTENT, QACHK-HORIZONTAL-BUDGET, and QACHK-PRIMARY-ACTION-REACHABILITY, reject bare PASS claims without numeric branch evidence. This costs one cheap turn. The defects these checks catch — clipped headings, invisible buttons, placeholder cards — are invisible to compile_canvas, so if you skip this the app ships broken while reporting clean.
• If any builder says checks 42-44 are undefined, stop instead of rerunning self-QA. Report the guide path and highest defined check as Status: Provenance Blocked.
• A self-QA follow-up is not a rebuild or a screen-generation re-dispatch. Tell the builder to inspect and repair the existing target file, then return the corrected QA coverage, repairs, and N/A lines without regenerating the screen.
• Compare every repeated navigation block against [working directory]/canvas-app-shared.md: same destination items, same order, no extra brand/label injected into one screen's nav, and width formulas that fit the narrowest target. This is an app-wide check builders cannot perform because each sees only one screen.
• In CREATE mode, inspect every planned screen file and reject a root-only screen. Each screen must contain at least one meaningful visible leaf control beneath its screen root; the screen root and layout containers do not count. Repair any missing screen content before entering final validation. A clean compile alone does not prove that the generated controls reached the coauthoring session.
• Verify each ## Action Contracts row end to end against the generated files: the entry point is reachable, the named event is wired, and the observable result is visible immediately after the action. For mutations, require an in-viewport receipt bound to the returned record, changed stable ID, or deletion snapshot. Compare the handler formula, declared write set, declared proof set, and receipt controls one-for-one. For create/edit, every user-entered or user-selected field written by the handler needs a readable labeled receipt binding. Navigation, a notification, hidden state, or a row somewhere in a longer list cannot replace it. Compile success does not prove runtime usability.
• Verify each ## Mutation Lifecycle Evidence row against final YAML: receipt, canonical-source observer, requested-destination observer, synchronization/focus, and operation all retain one stable ID. If source and destination differ, synchronization must occur only after mutation success and before destination evidence.
• Verify each ## Mutation Field Ledger row against the handler. Every Changed field has write/proof parity and one labeled receipt binding. Every Preserved field comes from canonical pre-state, survives by omission or exact carry-forward, and has post-state evidence for the same ID.
• When ## Continuation Contracts exists, verify create's returned ID directly targets the declared later edit/delete/relationship/approval/transition, and both completion and cancellation clear continuation ID/mode. Do not require this section for create-only flows.
• When ## State-Driven Surface Visibility exists, require one acceptance row per plan key with the exact final-YAML Surface.Visible: =state predicate binding. Verify the named surface itself implements the planned predicate or a provably equivalent Boolean form. Child visibility and navigation do not satisfy the surface contract. Do not infer this contract for always-visible or undeclared surfaces.
• For opposing mutation pairs, verify both contracts and scenarios against final YAML. Shared-operation selectors are selection-only, one reachable guarded event owns the mutation, selected-ID and operation state are reset and consumed consistently, invalid inputs disable submission, and receipt arithmetic matches the persisted result. Independently gated direct-action controls remain valid when no shared mutation event exists. Apply the exact control, state, guard, and formula checks from ${PLUGIN_ROOT}/references/ValidationWorkflow.md; acceptance prose never overrides final code.
• Execute every ## Functional Test Matrix row symbolically against the final formulas. Confirm the Given state makes the entry point eligible, the When event targets the declared source and stable ID, the Then values follow from the operation, and the evidence formula reads that post-state. Repair the owning file when any link depends on an unstated assumption or a different source/field.
• For every primary-record list, verify each row or its immediately reachable detail renders the canonical human-readable identity as full visible text. Avatar initials, icons, record IDs, accessible labels, or evaluator inference cannot replace the identity.
• Verify every ## Required Record Fields row against final YAML. The named control must exist inside the declared record surface, bind the current record's required source field, and remain visible, non-zero-sized, readable, and inside the card or row in the normal desktop and phone layouts. Repair missing, hidden, blank, clipped, or displaced fields, then compile and repeat this field check before writing acceptance evidence.
• Verify numeric layout evidence proves required record fields, actions, inputs, receipts, Gallery rows, and fixed-height or horizontal branches fit their reachable desktop and phone layouts. Static budgets do not replace post-export runtime proof for list rows and row actions. Apply the exact containment, sizing, breakpoint, and scrolling rules from ${PLUGIN_ROOT}/references/QAChecks.md and ${PLUGIN_ROOT}/references/ValidationWorkflow.md.
• Verify every Viewport Containment Contract against final YAML. The declared AutoLayout root must be the sole top-level child with exact viewport width/height; do not accept QACHK-ROOT-CONTAINMENT N/A on these screens.
• Verify fixed-height text-bearing controls against their longest reachable values. Include wrapped lines and padding; parent wrapping cannot prevent child-height clipping.
• Verify every Temporal Ordering Contract against final YAML. Test representative morning and afternoon values, zero-padded and non-padded 24-hour input, 12-hour input when accepted, and invalid/blank input. Direct lexicographic sorting of display strings fails.
• Require persistent human-readable visible labels for accepted data-entry controls, including controls on state-driven surfaces, and record the corresponding Data Entry Label Evidence from ${PLUGIN_ROOT}/references/ValidationWorkflow.md.
• When Approve and Reject/Decline are paired contracts, verify every eligible pending record exposes both decisions on the same row or the same immediately reachable detail at phone width. Send the owning screen back when either decision is missing; never accept a single-sided review queue as a density tradeoff.
• For every create/edit lifecycle, verify short static choices use radio buttons, visible choice buttons, or a dropdown that commits by click or tap without typed filtering, then trace create → bound mutation receipt → visible Edit → prepopulated form → stable-ID save → bound mutation receipt with updated values. At phone width, verify identity, status, and required lifecycle actions remain visible or have an immediately visible overflow/detail entry. Send only the owning screen back for self-QA when any link is missing.
• Reject QACHK-CARD-PLACEHOLDER PASS when a ModernCard displays Title, Subtitle and Description with Height < 180; send that screen back for self-QA.
• If a builder returns Status: Blocked, re-invoke the planner to correct that screen brief, then rerun only the affected builder. Never ask a builder to guess missing definitions.
• If a general-purpose screen worker cannot write its target, stop and report the exact tooling failure. Do not retry with a custom screen builder whose write restriction is already known.
• If a builder returns Status: Provenance Blocked, stop the wave without a fallback and report the mismatched plugin root or contract version.
• Status: Blocked is the only reason to repair a brief and rerun its specialist generation. Tooling failures stop the run. Compile diagnostics trigger neither path. Once a screen file exists, repair it in place with targeted edits; regenerating it discards prior fixes and does not converge.
• In EDIT mode, apply the ### After builders group of ## App Changes in [working directory]/canvas-app-plan.md to [working directory]/App.pa.yaml. The ### Before builders group was already applied at pre-dispatch. If a group says None, do not edit the file for it.
• The orchestrator is the sole owner of EDIT changes to [working directory]/App.pa.yaml.
• Apply ## Editor State Changes from [working directory]/canvas-app-plan.md to [working directory]/_EditorState.pa.yaml after all builders finish. If it says None, leave the file unchanged.
• Read ${PLUGIN_ROOT}/references/ValidationWorkflow.md and follow it.
• Complete every app, planning, and acceptance-artifact write before the final compile. The final successful compile_canvas must occur after the last edit, create, or apply_patch and must be the final tool call before the summary. After it succeeds, return the summary immediately without calling Task, read_agent, view, glob, rg, Bash, another MCP tool, or any other tool. If any later tool call, delegation, write, inspection, or repair occurs, the compile is no longer final: finish that work, wait for every agent, and repeat the final generation-proof gate.

Shared Invariants

1. Never guess control properties. Use describe_control; only use properties returned for that exact control type.
2. Use exact RGBA values and shared variable names from approved plans.
3. Control names are unique across the entire app, not per screen. Two screens may not both contain a control named NavBar or btnBack; the compiler rejects the second with An entity with name '...' already exists. Every control a builder writes uses the standard control-type abbreviation followed by that screen's assigned name prefix, such as conDiscNavBar or btnDetailBack. This applies especially to UI blocks repeated on many screens — nav bars, headers, toolbars, badges.
4. Copy control creation keywords from describe_control. list_controls provides the name used to query describe_control; it is not the authority for authored YAML. Copy the returned Control: value and every required ComponentName, ComponentLibraryUniqueName, Variant, and Layout keyword verbatim. Never strip, normalize, or reconstruct those values.
5. Never invent an enum type name. describe_control prints the exact name on the Enum name: line of each enum property. Copy it verbatim. Enum names do not follow from control names: Badge.Appearance is BadgeCanvas.Appearance, Progress.Shape is Progress.Shape, and ModernDropdown.Appearance is just Appearance. An enum member that starts with a digit must be quoted too — DecimalPrecision.'1', never DecimalPrecision.1, which fails with Expected operator and Expected an operand rather than Name isn't recognized.
6. In CREATE mode, reuse [working directory]/Screen1.pa.yaml for the landing screen and set App.StartScreen to =Screen1.
7. Never navigate from App.OnStart or the start screen's OnVisible.
8. Keep mock data compact: roughly 5-8 short rows per collection.
9. Builders own exactly one screen file. The planner owns CREATE-mode App.pa.yaml. The orchestrator owns EDIT-mode App.pa.yaml.
10. Compile early and often. App.pa.yaml is validated before builders are dispatched, and again as soon as the first builder returns. Never defer the first compile until every file is written.
11. Compile after each builder wave.
12. Do not report completion until the workspace compiles clean, every Action Contract has a passing evidence row in [working directory]/canvas-app-acceptance.md, and no app YAML mutation occurred after the final successful compile.
13. Require only prompt- or approved-plan-derived actions. Treat role-scoped management of primary records as a lifecycle requirement, but do not add universal CRUD to every entity.