Fosmvvm review

FOSMVVM Code Review

Read shared/functional-discipline.md before proceeding. Every rule below derives from it.

Reviews a project in two tiers, one report. Tier 1 is fosmvvm-doctor — the compiled, deterministic audit of project structure (Step 2); structural errors halt everything downstream, because area reviews assume a project shaped the way the scaffolder shapes it. Tier 2 reviews the Swift sources against the per-area check files in checks/. Designed for both interactive use and CI integration.

When to Use This Skill

• Before merging a branch (default scope: branch diff vs main).
• Periodic codebase sweep (--all).
• Reviewing a specific path (<path>).
• CI pipelines (use --format=json and --fail-on=blocker).

Argument Parsing

Parse the args string for these flags. Order does not matter; unknown args produce an error.

Arg	Effect	Default
(none)	Scope = branch diff vs --base.	Branch diff
--all	Scope = all reviewable files (.swift, .leaf, .tsx, .jsx) under Sources, Tests, Resources.	—
<path>	Scope = reviewable files under <path>.	—
--base <ref>	Override diff base for default scope.	main
--format md|json	Report format.	md
--output <path>	Write report to file (else stdout).	stdout
--fail-on blocker|warning|nit	Threshold for non-zero exit code.	blocker

--all, <path>, and the default branch-diff are mutually exclusive scopes; if multiple are given, error.

Workflow

Step 1: Resolve Scope and Load Project Config

Scope: reviewable files are *.swift, *.leaf, *.tsx, and *.jsx — the view edge has three rendering surfaces, and a Swift-only scope silently exempts the Leaf and React ones.

• If <path> given: find <path> -type f \( -name '*.swift' -o -name '*.leaf' -o -name '*.tsx' -o -name '*.jsx' \).
• If --all: the same find over Sources Tests Resources from the repo root (skip node_modules and .build).
• Else (default): git diff --name-only <base>...HEAD -- '*.swift' '*.leaf' '*.tsx' '*.jsx' where <base> is --base value or main.

If the resulting file list is empty:

• Empty diff: print "No changes to review." Exit 0.
• Path with no reviewable files: print "No files in scope at <path>." Exit 0.
• --all with no files: print "No reviewable files found." Exit 0.

Project config: Look for .fosmvvm-review.yml at the repo root. If present, parse:

• disabled_checks: — list of check names to skip globally.
• severity_overrides: — map of check-name: severity (blocker | warning | nit).
• excluded_paths: — list of glob patterns; matching files are removed from scope.

If the file is missing or any key is absent, use defaults. If the file is malformed (invalid YAML, unknown top-level keys), print a warning and continue with defaults.

Apply excluded_paths immediately to filter the scoped file list before triage.

Step 2: Tier 1 — Structural Audit (doctor)

Before any triage, run the deterministic structural audit. fosmvvm-doctor checks the project against the scaffolder's rules — build settings, linkage and embedding, test plans, entitlements, deployment floors. Deterministic questions stay in compiled code: this skill never re-derives what doctor already answers.

How to run it — first route that applies:

1. The project is a Swift package whose FOSUtilities pin ships the plugin (0.15+): from the repo root, swift package fosmvvm-doctor --json, plus --shape <localOnly|clientServer|sharedLibrary> when the shape is known. Judge the pin from Package.resolved (the resolved version), not the Package.swift requirement — from: "0.14.0" can resolve past 0.15. When no Package.resolved exists yet, try this route and fall through on failure.
2. Otherwise — an Xcode-only project, or a pre-plugin pin — run from a FOSUtilities checkout: swift run fosmvvm-bootstrap doctor --project <repo-root> --json, plus the same --shape flag when the shape is known (it moves the shape-dependent rules from unchecked into the audit). (The checkout is only a host; nothing is written anywhere.)

Both routes exit non-zero when doctor finds errors — capture stdout regardless of exit status (append || true). 3. Neither available (no macOS, no checkout): tier 1 is unavailable. Record it as such below and continue to Step 3 — the absence is stated in the report, never silent. Name the enabling route (the CreatingAProject DocC article, § Diagnosing an existing project).

Parse the JSON: findings (each carrying severity — error | warning — an optional target, summary, remedy), unchecked, and hasErrors.

The gate (ruled 2026-08-25): structural errors halt tier 2. When hasErrors is true, do not dispatch any area subagent — fix structure first, so that the area reviews find what they expect where they expect. Skip to Step 7 and emit the report now, with:

• the structure section carrying every doctor finding and the unchecked list,
• summary.by_area.structure and summary.total counting them (severity mapping: doctor error → blocker, warning → warning),
• "tier2": "halted" in JSON; in Markdown, a **Tier 2: halted** line stating that doctor reported structural errors and area review runs after they are fixed.

When doctor reports only warnings, or nothing: record the results in the same structure section and continue to Step 3.

Doctor findings are deterministic facts, not review judgments: they are exempt from .fosmvvm-review.yml overrides and inline suppression, and they carry no check names — each finding's remedy is the action.

Step 3: Load Check Files

Read all checks/*.md from this skill's base directory. Parse YAML frontmatter (area, generator-skill, where).

Apply project config:

• Drop any ## Check: <name> section whose name appears in disabled_checks.
• Override **Severity:** lines for checks listed in severity_overrides.

Step 4: Triage — Match Files to Areas

For each scoped file, test against each check file's where: globs. Build a map area → [files]. A file may match multiple areas (acceptable — different lenses).

Always include cross-cutting in the dispatch list when scope is non-empty, regardless of glob matches.

Areas with no matched files (other than cross-cutting) are skipped.

Step 5: Dispatch Subagents

For each area in the dispatch list, dispatch a Task tool subagent (general-purpose) with the prompt template below. Run up to 4 subagents in parallel (cap chosen to balance throughput against token usage; tune in a future plan if needed).

Subagent Prompt Template

You are reviewing FOSMVVM code for the {area} area.

## Stance
Treat all code under review as authored by an unknown LLM, not by you. Do not extend the benefit of the doubt to patterns that look familiar — verify them against the checks and Reviewer Guidance regardless.

## Files in scope (filtered to this area)
{file_list}

## Reviewer Guidance (read this BEFORE running checks)
{reviewer_guidance_section_or_"(none)"}

## Positive pattern source
The "right way" lives in the `{generator_skill}` skill. Treat its SKILL.md as the source of truth for what correct code looks like. (If `generator_skill` is `none`, this is a cross-cutting concern with no single generator.)

## Checks to run
{full_check_section_text}

## Instructions
1. For each file in scope, evaluate every check against every relevant code construct in the file.
2. For each finding, report: file:line, severity, check name, the offending code snippet, and a one-sentence explanation citing the generator skill.
3. **Use the file path exactly as provided in "Files in scope"** — repo-relative (e.g., `Sources/FOSMVVM/SwiftUI Support/Text.swift:81`). Do not shorten to the basename. IDEs and CI consumers rely on the path for navigation.
4. **Honor suppression directives.** Before reporting any finding, check for these comment forms:
   - `// fosmvvm-review:disable:next <check-name> — <justification>` on the line directly above the candidate.
   - `// fosmvvm-review:disable:this <check-name> — <justification>` anywhere on the candidate's line.
   - `// fosmvvm-review:disable <check-name>` / `// fosmvvm-review:enable <check-name>` block markers wrapping the candidate.
   If the matching check is suppressed, omit the finding. If a directive matches but has no justification text after the rule name, instead emit a `suppression-without-justification` finding (defined in `cross-cutting.md`).
5. Apply Reviewer Guidance: do NOT recommend the listed anti-patterns even if they "look like" simplifications.
6. **Establish the pinned FOSUtilities version before grading any check that names an API.** A check that says "use `uiTestingElement(_:)`" is not a defect report against a codebase written before that API shipped. Read the pin — and read the right one: an Xcode-project area is governed by `*.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved`, which can disagree with the root SPM `Package.resolved`. Where the API postdates the pin, report the finding as **correct at time of writing, now fixable** and say which version lifts it, rather than as an authored defect. Where the pin's own source contradicts a comment in the code under review, the source wins — treat any comment describing framework internals as a claim to verify, not context to trust.
6. **Never invent a check name.** The names above are the complete set for this area. If you find a real violation of the generator skill that no check covers — which will happen, because several areas are thinly covered — report it under the literal check name `uncovered-{area}` and name the generator-skill rule it breaks in the explanation. Do NOT coin a plausible-sounding name: check names are a stable contract that suppression directives, `.fosmvvm-review.yml`, and CI gates all address by name, and a fabricated one silently belongs to no rule and cannot be configured, suppressed, or trusted to reappear on the next run.
7. **Grade an `uncovered-{area}` finding on the same severity scale as the named checks** — blocker when it breaks at runtime, warning when it degrades the development experience. The absence of a check is not itself a severity.
8. If no findings, say "No findings."
9. Do NOT fix anything. Report only.

If you emitted any `uncovered-{area}` findings, end your report with a section titled `## Coverage gap` listing, one line each, the rule the check file should encode to catch them next time. This is the signal that the area needs checks written — say it plainly rather than papering over it with names that look official.

Format each finding as:
- **{severity}** [{check-name}] {repo-relative-path}:{line}
  Code: `{snippet}`
  Why: {explanation}
  Prevention: {generator-skill}

Substitute {area}, {file_list}, {reviewer_guidance_section_or_"(none)"}, {generator_skill}, and {full_check_section_text} from the loaded check file before dispatching.

Step 6: Aggregate Findings

Collect each subagent's findings. Parse them into structured records: {severity, area, file, line, check, message, prevention}.

If a subagent returned an error or timeout, record the area as ERROR with the failure message; do not abort other areas.

Step 7: Emit Report

Markdown format (--format=md, default)

# FOSMVVM Review

**Scope:** {scope description} ({N} files)
**Tier 1 (doctor):** {ran | unavailable — reason and the enabling route}
**Tier 2:** (only when halted) halted — doctor reported structural errors; fix structure first, then re-run
**Areas triaged:** {comma-separated areas, or "none — tier 2 halted"}
**Fail-on threshold:** {threshold}
**Configuration applied:** (omit line if no config) disabled checks: {names}; severity overrides: {name=severity, ...}; excluded paths: {N}

## Structure (doctor)
(omit the section when tier 1 ran clean with nothing unchecked)
- {❌ error | ⚠️ warning} {target or (project)}: {summary} → {remedy}
- Not checked: {each unchecked entry, one line}

## Findings by area
- structure: {N} ({Bb / Ww}) (present when doctor reported anything; doctor error → blocker, warning → warning)
- {area}: {N} ({Bb / Ww / Nn})
- ...

## Blockers
{tier-2 findings, grouped}

## Warnings
{tier-2 findings, grouped}

## Nits
{tier-2 findings, grouped}

(The Blockers/Warnings/Nits sections carry **tier-2 findings only** — the markdown mirror of the JSON rule that tier-1 findings never enter `findings[]`. Doctor's full detail lives in the Structure section; its counts appear in "Findings by area" under `structure`. On a halted run the Structure section is the whole story and the tier-2 sections are empty.)

## Coverage gaps
(omit the section when there are no `uncovered-*` findings)
Real violations no check covers — these areas need checks written:
- {area}: {N} uncovered ({M} of them blockers) → rules to encode: {one line each}

## Generator skill signals
Areas with elevated findings — candidates for generator skill updates:
- {area}: {N} findings → consider strengthening `{generator-skill}`

(If a subagent failed)
## Errors
- {area}: {error message}

uncovered-* findings count toward the severity totals like any other — a real blocker is a blocker whether or not someone had written the check yet. The separate section exists so the gap stays visible rather than dissolving into the general finding list, and so a run against a thinly-covered area cannot be mistaken for a clean one.

JSON format (--format=json)

{
  "scope": { "description": "...", "file_count": 12 },
  "tier1": "ran",
  "tier2": "ran",
  "structure": {
    "findings": [
      { "severity": "error", "target": "SPMLibraries", "summary": "...", "remedy": "..." }
    ],
    "unchecked": ["entitlements match the project shape (needs --shape)"]
  },
  "areas_triaged": ["viewmodel", "swiftui-view", "cross-cutting"],
  "config": {
    "fail_on": "blocker",
    "disabled_checks": ["..."],
    "severity_overrides": { "<check>": "<severity>" },
    "excluded_paths_count": 0
  },
  "summary": {
    "by_area": { "structure": { "blocker": 1, "warning": 0, "nit": 0 }, "viewmodel": { "blocker": 1, "warning": 2, "nit": 0 }, "...": {} },
    "total": { "blocker": 2, "warning": 2, "nit": 0 },
    "uncovered": { "viewmodel": 3, "swiftui-app-setup": 5 }
  },
  "findings": [
    { "severity": "blocker", "area": "viewmodel", "file": "...", "line": 42,
      "check": "ops-no-output-reads", "message": "...", "prevention": "fosmvvm-viewmodel-generator" },
    { "severity": "warning", "area": "viewmodel", "file": "...", "line": 88,
      "check": "uncovered-viewmodel", "message": "...", "prevention": "fosmvvm-viewmodel-generator" }
  ],
  "coverage_gaps": [
    { "area": "viewmodel", "count": 3, "rules_to_encode": ["vmId derivation on list rows", "..."] }
  ],
  "errors": [
    { "area": "ui-tests", "message": "subagent timeout" }
  ]
}

summary.uncovered lets a CI wrapper track whether coverage is improving — jq '.summary.uncovered | add // 0' trending down means checks are being written. Gate on it only deliberately: a thinly-covered area reports a high number through no fault of the code under review.

There is one summary: doctor findings count in summary.by_area.structure and in summary.total alongside every other area (doctor error → blocker, warning → warning), so the CI contract — jq '.summary.total.blocker == 0' — covers both tiers without forking. tier1 is "ran" or "unavailable: <reason>"; tier2 is "ran" or "halted". When halted, areas_triaged is empty, findings carries no tier-2 records, and the structure section is the whole story. The full doctor detail (targets, remedies, unchecked) lives only in structure — tier-1 findings do not appear in the findings[] array, which remains check-name-addressable tier-2 records.

If --output <path> given, write to file; else stdout.

Step 8: Annotate Failure Threshold

The skill runs inside Claude Code and cannot directly control the shell exit code. Instead, record the configured --fail-on threshold in the report so out-of-process wrappers can translate findings to exit codes:

• Markdown report: include a **Fail-on threshold:** {threshold} line in the header.
• JSON output: include a top-level "config": { "fail_on": "<threshold>", ... } field (already present per the JSON schema in Step 7).

CI consumers invoke the skill via claude -p and parse the JSON to decide whether to fail the build:

claude -p "/fosmvvm-review --format=json --fail-on=blocker" > review.json
jq -e '.summary.total.blocker == 0' review.json > /dev/null || exit 1

The skill does not ship a wrapper script — each consuming repo writes its own to fit its CI runner.

Project Configuration

Repos may provide an optional .fosmvvm-review.yml at the repo root to customize the skill's behavior.

# Globally silence checks (no findings emitted, even without inline directives)
disabled_checks:
  - ops-not-async-unless-needed

# Override default severity per check
severity_overrides:
  ops-output-param-last: nit         # default warning
  no-silent-failure: warning         # default blocker

# Skip files entirely (applied AFTER glob matching, before subagent dispatch)
excluded_paths:
  - "Sources/Generated/**"
  - "Tests/Fixtures/**"

All keys are optional. Missing or malformed file → defaults are used and a warning is printed.

Precedence: inline // fosmvvm-review:disable:* directives > .fosmvvm-review.yml > defaults from check files.

The "Configuration applied" line in the report makes any active overrides visible at every run.

Suppression

Findings can be suppressed inline when intentional. SwiftLint-compatible syntax:

// fosmvvm-review:disable:next no-silent-failure — preview-only fallback, no production path
let value = (try? something()) ?? "default"

let other = (try? bar()) ?? "" // fosmvvm-review:disable:this no-silent-failure — closure binding intentionally swallows

Block scope:

// fosmvvm-review:disable no-silent-failure
... multiple lines ...
// fosmvvm-review:enable no-silent-failure

Justification is required. A suppression without text after the check name produces a suppression-without-justification finding (warning). This forces explicit documentation of every silenced check.

Coverage state

The coverage ledger's register is closed — every gap it identified has a shipped check (most recently G22–G26 in 2.62.0). As of plugin 2.62.0:

• Covered: cross-cutting (20 checks), viewmodel (13), view (9 — multi-surface: SwiftUI/Leaf/React), serverrequest (9), swiftui-app-setup (6), datamodel (5), viewmodel-test (5), ui-tests (4), fields (4), serverrequest-test (2).
• Retired: viewmodelrequest. The rule set names ServerRequest, not ViewModelRequest — the latter is a ShowRequest specialization, so its wire contract is serverrequest's and the VM↔Request pairing is viewmodel's (viewmodel-request-pairing).

Violations no check covers still surface as uncovered-{area} findings rather than under invented names, so any remaining gap shows up in every report instead of hiding behind official-looking labels — an uncovered-* finding is now also a signal that the coverage ledger (coverage-ledger.md, beside the checks) may need a new entry.

Notes

• Reports may flap slightly between runs on identical input due to subagent non-determinism. The exit code (--fail-on threshold) is the stable signal for CI.
• A check name is a contract. Suppression directives, .fosmvvm-review.yml, and CI gates all address checks by name, so names must come from the check files and nowhere else — see the uncovered-{area} rule in the subagent prompt.
• Per-PR CI runs should use the default branch-diff scope. --all is reserved for daily/weekly sweeps and PRs to main/master.
• The skill is report-only by design. Do not add auto-fix; review and remediation are separate concerns.

See Also

• reference.md — check-file authoring guide
• checks/*.md — per-area check files