info-tech-canon/workplans/ITC-WP-0016-practice-pattern-language.md

id	type	title	domain	topic_slug	repo	status	priority	created	updated	owner	related	spec_refs
ITC-WP-0016	workplan	PracticePattern language and InterfaceDeprecationStrangler	infotech	canon	info-tech-canon	active	high	2026-08-21	2026-08-21	codex	STATE-WP-0079	infospace/patterns/PracticePatternScheme.md infospace/patterns/InterfaceDeprecationStrangler.md infospace/schemas/practice-pattern.schema.yaml arc-nexus/README.md

ITC-WP-0016 — PracticePattern language

Goal

Give recurring operational and architectural practices a stable, speakable pattern language in InfoTechCanon. Define a common Markdown scheme inspired by Christopher Alexander's pattern-language method, seed it with the proven InterfaceDeprecationStrangler, and record its adoption in arc-nexus.

T01 — Define the PracticePattern scheme

id: ITC-WP-0016-T01
status: progress
priority: high

Define the identity, lifecycle, required frontmatter, required problem/forces/ solution structure, evidence expectations, and relationship vocabulary for a versioned PracticePattern Markdown artifact. Add a machine-readable schema and canon validation for the contract.

T02 — Document InterfaceDeprecationStrangler

id: ITC-WP-0016-T02
status: todo
priority: high

Capture the reusable practice independently of State Hub: its context, forces, solution, staged dynamics, invariants, retirement evidence, failure modes, consequences, adoption checklist, and known use in State Hub.

T03 — Publish retrieval and navigation assets

id: ITC-WP-0016-T03
status: todo
priority: medium

Register the scheme and pattern in the artifact graph, schema catalog, pattern index, generated views, and agent retrieval assets. Validate that agents can retrieve the named practice without relying on the originating repository.

T04 — Reference the pattern from arc-nexus

id: ITC-WP-0016-T04
status: todo
priority: medium

State in arc-nexus that old architecture interfaces are phased out using the canonical InterfaceDeprecationStrangler PracticePattern, including the canon artifact ID and path and the local adoption expectations.

Acceptance

• PracticePattern Markdown artifacts have a documented and validated v0.1 scheme.
• InterfaceDeprecationStrangler is a registered, retrieval-visible canon artifact.
• The pattern distinguishes successful legacy traffic from attempted use of a retired interface.
• arc-nexus names the pattern and states how it applies locally.
• Canon validation and tests pass; both repositories are committed and synchronized.

Out of scope

• Automatically instrumenting consumer repositories.
• Rewriting every pre-existing candidate pattern in this workplan.
• Standardizing protocol-specific deprecation headers beyond requiring explicit caller guidance.