surface-parity

name	surface-parity
description	Internal closed-loop skill: drive CLI/API/MCP to 100% shape parity (same service methods) AND behaviour parity (same response shapes). Uses ESLint rules tx/require-surface-parity + tx/interface-parity. NOT shipped to tx users.
argument-hint	[--dry-run] [--service ServiceName]
metadata	{"short-description":"Internal: shape + behaviour parity loop"}

Internal skill (not shipped to users). Drives two dimensions of parity across all surfaces (CLI/API/MCP):

1. Shape parity — every core service method present on ANY surface must be present on ALL surfaces
2. Behaviour parity — those methods must return identical response shapes, use shared serializers, and handle errors consistently

Checked by two ESLint rules:

• tx/require-surface-parity — shape (service method coverage + variable naming)
• tx/interface-parity — behaviour (response shapes, serializer dedup, field types)

Loop Workflow

STEP 1 → Audit both rules
STEP 2 → Fix naming violations (enables accurate shape detection)
STEP 3 → Fix shape gaps (implement missing service methods on surfaces)
STEP 4 → Fix behaviour gaps (align response shapes, use shared serializers)
STEP 5 → Re-audit → if clean, done; else goto STEP 2

Step 1: Audit

# Shape parity: naming + method coverage
bunx eslint --no-cache apps/cli/src/commands/task.ts 2>&1 | grep 'require-surface-parity'

# Behaviour parity: response shapes + serializers
bunx eslint --no-cache apps/cli/src/commands/task.ts 2>&1 | grep 'interface-parity'

# Combined count (loop exit condition: 0)
bunx eslint --no-cache apps/cli/src/commands/task.ts 2>&1 | grep -c 'require-surface-parity\|interface-parity'

Step 2: Fix Naming Violations

Naming violations look like:

23:11  warning  Service binding "svc" should be "taskService' or 'taskSvc" (from TaskService).

Fix by renaming the variable AND all its usages within the same Effect.gen scope:

// BEFORE
const svc = yield* TaskService
yield* svc.create(input)

// AFTER
const taskService = yield* TaskService
yield* taskService.create(input)

Fix naming FIRST — the shape parser relies on consistent naming for accurate method attribution.

Step 3: Fix Shape Gaps

Shape gaps look like:

Surface parity gap: LearningService.count is missing from cli (implemented in: api, mcp)

For each gap, implement the missing operation on the missing surface. Follow the existing patterns in:

• CLI: apps/cli/src/commands/<domain>.ts — Effect.gen + yield* service.method() + toJson()/console.log()
• API: apps/api-server/src/routes/<domain>.ts — .handle() + Effect.gen + serializeX() + mapCoreError
• MCP: apps/mcp-server/src/tools/<domain>.ts — runEffect(Effect.gen(...)) + JSON text content blocks

Step 4: Fix Behaviour Gaps

Behaviour gaps look like:

Interface parity violation: done response missing required field "nowReady".
Interface parity violation: Local serializeTask() duplicates shared function.

Fixes:

• Missing response fields: add the field to the response object (e.g. { task, nowReady })
• Duplicate serializers: delete local serializeTask(), import from @jamesaphoenix/tx-types
• ID arrays instead of tasks: use .map(serializeTask) not .map(t => t.id)

Step 5: Re-Audit

bunx eslint --no-cache apps/cli/src/commands/task.ts 2>&1 | grep -c 'require-surface-parity\|interface-parity'

If 0: done. If >0: go back to Step 2.

Current Gap Summary

Shape gaps (19):

• LearningService: 8 gaps (CLI missing create/get/search/getRecent/updateOutcome/count; MCP missing get/getRecent)
• FileLearningService: 3 gaps (CLI missing create/getAll/recall)
• ReadyService.readyAndClaim: 2 gaps (API + MCP missing)
• TaskService.get: 2 gaps (API + MCP missing — DOCTRINE RULE 1 tension)
• MemoryService.search: 2 gaps (API + MCP missing)
• HierarchyService.getTree: 1 gap (CLI missing)
• GuardService.check: 1 gap (CLI missing)

Behaviour gaps: run bunx eslint --no-cache apps/ 2>&1 | grep 'interface-parity' to check current count.

Configuration

Shape rule in eslint.config.js:

'tx/require-surface-parity': ['warn', { ... }]

Behaviour rule in eslint.config.js:

'tx/interface-parity': ['error', { ... }]