{ "policy": { "version": 5, "patterns": { "version": 1, "method": "CURATED_PRACTICE_TOPIC", "notice": "Pattern topics identify design choices to practice. Read the ticket's acceptance criteria and justify the simplest suitable approach. Tags are not capability or ownership evidence; an untagged ticket has no curated pattern topic assigned." }, "fieldMix": { "version": 1, "method": "CURATED_ESTIMATE", "notice": "Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence." }, "contentStatus": "PRACTICE_BRIEF", "assessmentStatus": "NOT_QUALIFIED", "evidenceUse": "NONE", "aiPolicy": "AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior.", "notice": "Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included.", "outcomeEvidence": "Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.", "ownershipEvidence": "Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence." }, "patternTopics": [ { "id": "factory-method", "label": "Factory Method", "group": "Creational" }, { "id": "abstract-factory", "label": "Abstract Factory", "group": "Creational" }, { "id": "builder", "label": "Builder", "group": "Creational" }, { "id": "prototype", "label": "Prototype", "group": "Creational" }, { "id": "singleton", "label": "Singleton", "group": "Creational" }, { "id": "adapter", "label": "Adapter", "group": "Structural" }, { "id": "bridge", "label": "Bridge", "group": "Structural" }, { "id": "composite", "label": "Composite", "group": "Structural" }, { "id": "decorator", "label": "Decorator", "group": "Structural" }, { "id": "facade", "label": "Facade", "group": "Structural" }, { "id": "flyweight", "label": "Flyweight", "group": "Structural" }, { "id": "proxy", "label": "Proxy", "group": "Structural" }, { "id": "chain-of-responsibility", "label": "Chain of Responsibility", "group": "Behavioral" }, { "id": "command", "label": "Command", "group": "Behavioral" }, { "id": "interpreter", "label": "Interpreter", "group": "Behavioral" }, { "id": "iterator", "label": "Iterator", "group": "Behavioral" }, { "id": "mediator", "label": "Mediator", "group": "Behavioral" }, { "id": "memento", "label": "Memento", "group": "Behavioral" }, { "id": "observer", "label": "Observer", "group": "Behavioral" }, { "id": "state", "label": "State", "group": "Behavioral" }, { "id": "strategy", "label": "Strategy", "group": "Behavioral" }, { "id": "template-method", "label": "Template Method", "group": "Behavioral" }, { "id": "visitor", "label": "Visitor", "group": "Behavioral" }, { "id": "ports-and-adapters", "label": "Ports and Adapters", "group": "Architectural" }, { "id": "cqrs", "label": "CQRS", "group": "Architectural" }, { "id": "strangler-fig", "label": "Strangler Fig", "group": "Architectural" }, { "id": "saga", "label": "Saga", "group": "Distributed and reliability" }, { "id": "transactional-outbox", "label": "Transactional Outbox", "group": "Distributed and reliability" }, { "id": "circuit-breaker", "label": "Circuit Breaker", "group": "Distributed and reliability" }, { "id": "bulkhead", "label": "Bulkhead", "group": "Distributed and reliability" } ], "projects": [ { "id": "c893cb7f-50c0-4eda-a668-7f9183b4a846", "key": "BCONTRACT", "title": "Consumer contract compatibility lab", "field": "Quality engineering", "summary": "Check independent client expectations against evolving provider behavior.", "context": "A fictional fulfillment API serves a web checkout and warehouse adapter. Provider tests pass while consumers fail on subtle response and error changes.", "stack": [ "TypeScript", "HTTP", "JSON Schema" ], "prerequisites": [ "Author two small local consumers and one mock provider with versioned synthetic responses." ], "developerValue": "Practice executable contracts, meaningful negative tests, and compatibility triage.", "companyValue": "Expose integration regressions before deployment without requiring every system to run together.", "delivery": "Deliver versioned public contract checks and a local compatibility report.", "phases": [ { "id": "capture", "title": "Capture expectations", "goal": "Identify consumer behavior that forms a real contract." }, { "id": "verify", "title": "Verify boundaries", "goal": "Exercise provider changes and error semantics." }, { "id": "adopt", "title": "Manage evolution", "goal": "Make compatibility decisions and exceptions reviewable." } ], "tickets": [ { "id": "0e278a74-f4e9-4569-bd90-775c9b53f32d", "key": "BCONTRACT-101", "title": "Inventory the fields each fulfillment consumer actually reads", "type": "TASK", "priority": "MEDIUM", "difficulty": "FOUNDATIONAL", "estimateMinutes": 60, "phaseId": "capture", "dependsOn": [], "scenario": "The existing contract copies entire sample responses, making harmless changes fail.", "acceptanceCriteria": [ "List fields and semantics used by each consumer.", "Distinguish optional fields from required decisions.", "Identify one response field neither consumer needs." ], "implementationNotes": [ "Use synthetic consumers rather than production traffic." ], "verification": [ "Trace checkout and warehouse reads.", "Remove an unused field without changing the consumer outcome." ], "deliverables": [ "Consumer expectation inventory." ], "rollout": "Review scope before creating strict assertions.", "skills": [ "Contract testing" ], "fieldMix": [ { "field": "Quality engineering", "percentage": 60 }, { "field": "API design", "percentage": 40 } ], "patterns": [] }, { "id": "1a4fa176-6a3d-42ef-8a37-e44564ca85b6", "key": "BCONTRACT-102", "title": "Create isolated provider states for contract examples", "type": "TASK", "priority": "HIGH", "difficulty": "INTERMEDIATE", "estimateMinutes": 150, "phaseId": "capture", "dependsOn": [ "BCONTRACT-101" ], "scenario": "Contracts depend on whichever orders happen to exist in a shared test database.", "acceptanceCriteria": [ "Create named states with deterministic synthetic identities.", "Reset each state independently.", "Reject unrecognized state names instead of selecting a default." ], "implementationNotes": [ "State setup is accessible only inside the local harness." ], "verification": [ "Run states in either order.", "Request an unknown state and verify no default data leaks." ], "deliverables": [ "Provider-state fixture harness." ], "rollout": "Use the isolated harness for new contracts; retire shared mutable fixtures.", "skills": [ "Fixtures", "Test isolation" ], "fieldMix": [ { "field": "Quality engineering", "percentage": 100 } ], "patterns": [] }, { "id": "c575e385-f8f5-4f25-9e4f-562f476616ed", "key": "BCONTRACT-103", "title": "Protect decimal quantities from implicit numeric coercion", "type": "BUG", "priority": "HIGH", "difficulty": "INTERMEDIATE", "estimateMinutes": 120, "phaseId": "verify", "dependsOn": [ "BCONTRACT-102" ], "scenario": "The warehouse adapter rounds fractional unit quantities after a provider changes strings to numbers.", "acceptanceCriteria": [ "Specify quantity representation and allowed scale.", "Reject excess precision and non-finite values.", "Verify consumer arithmetic preserves the declared quantity." ], "implementationNotes": [ "Use exact decimal arithmetic or integer units." ], "verification": [ "Process a supported fractional quantity.", "Reject scientific-notation and overprecision examples where unsupported." ], "deliverables": [ "Quantity contract regression." ], "rollout": "Treat representation changes as reviewed compatibility changes.", "skills": [ "Data contracts", "Numeric correctness" ], "fieldMix": [ { "field": "Quality engineering", "percentage": 60 }, { "field": "API design", "percentage": 40 } ], "patterns": [] }, { "id": "41f1bd6d-e324-4e47-b494-2392cde220d3", "key": "BCONTRACT-104", "title": "Verify unknown enum values do not crash old clients", "type": "TASK", "priority": "MEDIUM", "difficulty": "ADVANCED", "estimateMinutes": 180, "phaseId": "verify", "dependsOn": [ "BCONTRACT-102" ], "scenario": "A new fulfillment status reaches a client compiled against the previous enum.", "acceptanceCriteria": [ "Define unknown-status behavior for each consumer.", "Preserve the raw value for safe diagnostics.", "Avoid treating unknown as delivered or cancelled." ], "implementationNotes": [ "Unknown states must not trigger irreversible actions." ], "verification": [ "Handle every documented status.", "Feed a future status and verify conservative behavior." ], "deliverables": [ "Forward-compatible enum checks." ], "rollout": "Deploy tolerant readers before adding new provider values.", "skills": [ "Compatibility", "State modeling" ], "fieldMix": [ { "field": "Quality engineering", "percentage": 60 }, { "field": "API design", "percentage": 40 } ], "patterns": [] }, { "id": "51096f2c-ae27-49bb-b133-03ac4f86ef24", "key": "BCONTRACT-105", "title": "Test authorization before provider-state response lookup", "type": "BUG", "priority": "HIGH", "difficulty": "ADVANCED", "estimateMinutes": 180, "phaseId": "verify", "dependsOn": [ "BCONTRACT-102" ], "scenario": "A contract fixture returns an order by ID even when the caller belongs to another merchant.", "acceptanceCriteria": [ "Scope reads by authenticated merchant at the repository boundary.", "Use non-enumerating denial semantics.", "Keep privileged fixture setup unavailable to consumers." ], "implementationNotes": [ "Contract success must not bypass authorization." ], "verification": [ "Read an owned order.", "Request another merchant's order and compare safe denial behavior." ], "deliverables": [ "Cross-merchant contract cases." ], "rollout": "Block compatibility approval when tenant denial regresses.", "skills": [ "Authorization", "Contract testing" ], "fieldMix": [ { "field": "Quality engineering", "percentage": 50 }, { "field": "Security", "percentage": 50 } ], "patterns": [] }, { "id": "9de2c1c8-5f2d-4ebb-aca7-8087d9a6fec5", "key": "BCONTRACT-106", "title": "Cover retry semantics for conflicts and transient failures", "type": "TASK", "priority": "HIGH", "difficulty": "ADVANCED", "estimateMinutes": 180, "phaseId": "verify", "dependsOn": [ "BCONTRACT-103", "BCONTRACT-105" ], "scenario": "Both clients currently retry every failed write, including conflicting requests.", "acceptanceCriteria": [ "Distinguish conflict, validation, and transient errors.", "Specify which writes are safely retryable.", "Preserve request identity across allowed retries." ], "implementationNotes": [ "Use a deterministic mock clock and bounded retry count." ], "verification": [ "Recover from one transient error.", "Verify validation and conflicting idempotency reuse are not retried." ], "deliverables": [ "Error and retry contract suite." ], "rollout": "Adopt new error handling with the provider behavior unchanged.", "skills": [ "HTTP semantics", "Idempotency" ], "fieldMix": [ { "field": "Quality engineering", "percentage": 50 }, { "field": "API design", "percentage": 30 }, { "field": "Distributed systems", "percentage": 20 } ], "patterns": [] }, { "id": "0b92097b-5d43-4c1b-b2fc-f9a6b15d3e69", "key": "BCONTRACT-107", "title": "Detect undocumented response changes with focused mutation checks", "type": "TASK", "priority": "HIGH", "difficulty": "ADVANCED", "estimateMinutes": 210, "phaseId": "verify", "dependsOn": [ "BCONTRACT-103", "BCONTRACT-104", "BCONTRACT-106" ], "scenario": "A passing contract may only prove the mock matched itself.", "acceptanceCriteria": [ "Mutate one required field, status, or header per case.", "Show each relevant mutation makes a consumer expectation fail.", "Record intentionally tolerated mutations separately." ], "implementationNotes": [ "Mutations target public contract behavior only." ], "verification": [ "Catch a missing quantity and wrong conflict status.", "Tolerate an unrelated additive response property." ], "deliverables": [ "Contract sensitivity report." ], "rollout": "Review surviving mutations before trusting the contract gate.", "skills": [ "Mutation testing", "Test design" ], "fieldMix": [ { "field": "Quality engineering", "percentage": 100 } ], "patterns": [] }, { "id": "8b61cc3d-62c7-4798-9e93-7dcbaecf14be", "key": "BCONTRACT-108", "title": "Design a compatibility gate that handles missing consumers", "type": "TASK", "priority": "HIGH", "difficulty": "EXPERT", "estimateMinutes": 300, "phaseId": "adopt", "dependsOn": [ "BCONTRACT-107" ], "scenario": "A new provider build is marked compatible because one consumer stopped submitting its contract.", "acceptanceCriteria": [ "Require an explicit supported-consumer inventory.", "Distinguish failed, missing, stale, and passed verification.", "Define a reviewed exception with owner and expiry." ], "implementationNotes": [ "Absence of results cannot mean compatibility." ], "verification": [ "Pass with all supported consumers checked.", "Remove or stale one contract and block the gate." ], "deliverables": [ "Compatibility gate decision record." ], "rollout": "Start as advisory; enforce once inventory ownership is established.", "skills": [ "Release governance", "Compatibility" ], "fieldMix": [ { "field": "Quality engineering", "percentage": 60 }, { "field": "Platform engineering", "percentage": 40 } ], "patterns": [] }, { "id": "5a35c8aa-6c98-4388-a6b8-e6b9a5dd9c65", "key": "BCONTRACT-109", "title": "Generate a human-readable contract failure explanation", "type": "STORY", "priority": "MEDIUM", "difficulty": "INTERMEDIATE", "estimateMinutes": 120, "phaseId": "adopt", "dependsOn": [ "BCONTRACT-108" ], "scenario": "Engineers see a JSON diff but cannot tell which consumer behavior changed.", "acceptanceCriteria": [ "Name the consumer and contract revision.", "Show the relevant expected and observed public fields.", "Exclude credentials and unrelated payload content." ], "implementationNotes": [ "Bound output and redact synthetic secret markers." ], "verification": [ "Explain a changed error status.", "Verify oversized payloads and authorization headers are omitted." ], "deliverables": [ "Failure explanation formatter." ], "rollout": "Attach explanations to existing failed checks without altering outcomes.", "skills": [ "Developer experience", "Diagnostics" ], "fieldMix": [ { "field": "Quality engineering", "percentage": 60 }, { "field": "Developer tooling", "percentage": 40 } ], "patterns": [] }, { "id": "dc2b44f2-392f-4124-923d-d0a220c6d4d2", "key": "BCONTRACT-110", "title": "Rehearse retiring an unused consumer contract", "type": "CHORE", "priority": "LOW", "difficulty": "FOUNDATIONAL", "estimateMinutes": 60, "phaseId": "adopt", "dependsOn": [ "BCONTRACT-109" ], "scenario": "An abandoned warehouse client keeps blocking harmless provider changes.", "acceptanceCriteria": [ "Record owner confirmation and supported-version cutoff.", "Preserve the retired contract for history.", "Remove it from required checks only after the cutoff." ], "implementationNotes": [ "Do not delete active consumer coverage based solely on low test activity." ], "verification": [ "Retire a synthetic obsolete consumer.", "Verify an active consumer remains required." ], "deliverables": [ "Contract retirement procedure." ], "rollout": "Keep the last compatibility report available for rollback investigation.", "skills": [ "Lifecycle management", "Documentation" ], "fieldMix": [ { "field": "Quality engineering", "percentage": 70 }, { "field": "API design", "percentage": 30 } ], "patterns": [] } ] } ] }