{ "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": "09159d14-2fc2-426c-91cd-3728b0ebc2af", "key": "AARCHIVE", "title": "Design a searchable audit archive with retention boundaries", "field": "System design", "summary": "Choose storage, indexing and deletion semantics for a bounded audit archive.", "context": "A fictional procurement platform keeps append-only action records. Operators want fast recent search and affordable old records without losing provenance or leaking tenant data.", "stack": [ "PostgreSQL", "Object storage", "TypeScript" ], "prerequisites": [ "Create synthetic audit events and local storage/search adapters.", "Use an explicit fictional retention policy, not legal advice." ], "developerValue": "Practice storage tradeoffs, provenance and data-lifecycle decisions.", "companyValue": "Review archive cost and retrieval guarantees before committing to infrastructure.", "delivery": "Ten scoped tickets across three phases. Build a synthetic local service or select a ticket after recreating its prerequisites; estimates exclude setup.", "phases": [ { "id": "needs", "title": "Define archive guarantees", "goal": "Specify access, retention and search expectations." }, { "id": "contract", "title": "Model archive boundaries", "goal": "Make manifests, indexing and retrieval verifiable." }, { "id": "lifecycle", "title": "Challenge long-term behavior", "goal": "Rehearse retention, restoration and cost changes." } ], "tickets": [ { "id": "97196953-8185-4d77-8010-69f6a11aa840", "key": "AARCHIVE-101", "title": "Define which audit questions require indexed search versus archive retrieval", "type": "TASK", "priority": "MEDIUM", "difficulty": "FOUNDATIONAL", "estimateMinutes": 90, "phaseId": "needs", "dependsOn": [], "scenario": "The design says all audit history must be instantly searchable, but reviewers usually inspect the last week and rarely retrieve older cases.", "acceptanceCriteria": [ "List recent search and older retrieval use cases separately.", "State hypothetical latency and date-range targets.", "Identify fields that may be indexed without exposing payload contents." ], "implementationNotes": [ "Use fabricated events and a named review workflow." ], "verification": [ "Map a recent actor search to its target.", "Map an old case retrieval to the declared slower path without claiming instant search." ], "deliverables": [ "Archive access-pattern inventory" ], "rollout": "Review the inventory before choosing storage; keep unapproved fields out of indexes.", "skills": [ "Access-pattern analysis", "Requirements" ], "fieldMix": [ { "field": "System design", "percentage": 60 }, { "field": "Storage systems", "percentage": 20 }, { "field": "Database engineering", "percentage": 20 } ], "patterns": [] }, { "id": "fa35ba05-5cb4-41b3-8d70-5cf944a18c18", "key": "AARCHIVE-102", "title": "Calculate archive storage growth from event size and retention assumptions", "type": "TASK", "priority": "MEDIUM", "difficulty": "INTERMEDIATE", "estimateMinutes": 150, "phaseId": "needs", "dependsOn": [ "AARCHIVE-101" ], "scenario": "A budget proposal counts raw event bytes but omits index, replica and manifest overhead.", "acceptanceCriteria": [ "Model events per day, average bytes and retention duration.", "Show raw, index and redundancy components separately.", "Label compression and growth factors as assumptions." ], "implementationNotes": [ "Provide a small executable worksheet with no claimed measured savings." ], "verification": [ "Calculate the baseline synthetic scenario.", "Double event volume and vary compression to show sensitivity." ], "deliverables": [ "Storage-growth model" ], "rollout": "Use the model for a reviewed budget proposal; update it after real storage measurements.", "skills": [ "Capacity modeling", "Cost reasoning" ], "fieldMix": [ { "field": "System design", "percentage": 50 }, { "field": "Storage systems", "percentage": 30 }, { "field": "Cloud infrastructure", "percentage": 20 } ], "patterns": [] }, { "id": "ae94897e-1015-435b-89c6-973981d41f4f", "key": "AARCHIVE-103", "title": "Choose hot and cold archive boundaries with a reviewable decision record", "type": "TASK", "priority": "MEDIUM", "difficulty": "FOUNDATIONAL", "estimateMinutes": 120, "phaseId": "needs", "dependsOn": [ "AARCHIVE-101", "AARCHIVE-102" ], "scenario": "The team proposes a new search cluster before checking whether bounded PostgreSQL search and object retrieval satisfy the workload.", "acceptanceCriteria": [ "Compare existing database search with a separate index option.", "Include consistency, operational and restore costs.", "Choose the smallest option meeting the stated requirements." ], "implementationNotes": [ "Do not provision speculative infrastructure for this design exercise." ], "verification": [ "Evaluate both options against recent and old queries.", "Identify the threshold or query need that would reopen the decision." ], "deliverables": [ "Archive storage decision record" ], "rollout": "Review the decision against the workload model before implementing new infrastructure.", "skills": [ "Architecture decisions", "Tradeoff analysis" ], "fieldMix": [ { "field": "System design", "percentage": 50 }, { "field": "Database engineering", "percentage": 30 }, { "field": "Storage systems", "percentage": 20 } ], "patterns": [] }, { "id": "db9c63b5-57e8-4dbb-b889-7308fadd4dcb", "key": "AARCHIVE-104", "title": "Define an immutable archive segment manifest", "type": "TASK", "priority": "MEDIUM", "difficulty": "ADVANCED", "estimateMinutes": 210, "phaseId": "contract", "dependsOn": [ "AARCHIVE-103" ], "scenario": "An exported audit file has no trusted count or content identity, so operators cannot tell whether a partial upload is complete.", "acceptanceCriteria": [ "Manifest binds segment ID, record count, range and byte hash.", "Publish a segment only after verifying its stored identity.", "Retain original event identifiers across archival." ], "implementationNotes": [ "Use canonical synthetic serialization and exact object versions." ], "verification": [ "Archive and verify a complete segment.", "Truncate bytes or alter count and reject publication." ], "deliverables": [ "Segment contract and integrity probe" ], "rollout": "Prototype manifests alongside synthetic exports; keep unverified segments out of search.", "skills": [ "Integrity", "Storage contracts" ], "fieldMix": [ { "field": "Storage systems", "percentage": 50 }, { "field": "System design", "percentage": 30 }, { "field": "Security", "percentage": 20 } ], "patterns": [] }, { "id": "2f76ad51-190f-4ffb-980b-c3d3d7357ce2", "key": "AARCHIVE-105", "title": "Specify search indexing as a rebuildable projection of archived events", "type": "STORY", "priority": "MEDIUM", "difficulty": "ADVANCED", "estimateMinutes": 240, "phaseId": "contract", "dependsOn": [ "AARCHIVE-104" ], "scenario": "A search result is edited directly to correct an event, creating a version of history absent from the source archive.", "acceptanceCriteria": [ "Treat the index as a projection with source segment identity.", "Corrections append new events rather than rewrite archived facts.", "Define checkpoint and duplicate-indexing semantics." ], "implementationNotes": [ "Use an in-memory search adapter for the contract probe." ], "verification": [ "Rebuild the index from named manifests and preserve event identities.", "Replay a segment and verify no duplicate search records." ], "deliverables": [ "Index projection model and replay test" ], "rollout": "Build a shadow index generation; switch only after source-count reconciliation.", "skills": [ "Projection design", "Append-only modeling" ], "fieldMix": [ { "field": "System design", "percentage": 50 }, { "field": "Data engineering", "percentage": 30 }, { "field": "Database engineering", "percentage": 20 } ], "patterns": [] }, { "id": "029354cd-5126-43f7-9d74-939acc35ce20", "key": "AARCHIVE-106", "title": "Authorize archive retrieval before issuing object capabilities", "type": "TASK", "priority": "HIGH", "difficulty": "EXPERT", "estimateMinutes": 300, "phaseId": "contract", "dependsOn": [ "AARCHIVE-104", "AARCHIVE-105" ], "scenario": "An audit search hit contains a raw object key; clients can request other tenants' segments by changing that key.", "acceptanceCriteria": [ "Resolve event and segment within the caller's authorized tenant.", "Issue a capability scoped to the exact object version.", "Avoid exposing neighboring events through shared-segment retrieval." ], "implementationNotes": [ "Choose per-tenant segments or a server-side filtered retrieval contract." ], "verification": [ "Retrieve a permitted synthetic event through the chosen boundary.", "Alter tenant or segment identity and verify no capability is issued." ], "deliverables": [ "Archive access contract and cross-tenant probe" ], "rollout": "Keep raw objects private; enable retrieval only after the projection isolation checks pass.", "skills": [ "Authorization architecture", "Data isolation" ], "fieldMix": [ { "field": "Security", "percentage": 50 }, { "field": "System design", "percentage": 30 }, { "field": "Storage systems", "percentage": 20 } ], "patterns": [] }, { "id": "01b13afd-0755-47f6-84f7-5370df891389", "key": "AARCHIVE-107", "title": "Define archive query pagination across hot and cold boundaries", "type": "STORY", "priority": "MEDIUM", "difficulty": "INTERMEDIATE", "estimateMinutes": 180, "phaseId": "contract", "dependsOn": [ "AARCHIVE-103", "AARCHIVE-105", "AARCHIVE-106" ], "scenario": "A query spanning the archive cutoff repeats recent events and misses records moved between stores during pagination.", "acceptanceCriteria": [ "Bind the cursor to a declared snapshot or generation.", "Specify stable ordering and deduplication by event identity.", "Return explicit partial or unavailable states for missing segments." ], "implementationNotes": [ "Model movement with local fixtures rather than live archive jobs." ], "verification": [ "Page across a cutoff while a segment moves and retain complete ordering.", "Make one segment unavailable and report the gap without a complete-result claim." ], "deliverables": [ "Cross-store query contract and boundary cases" ], "rollout": "Canary bounded date queries; fall back to separate hot/cold retrieval if completeness is uncertain.", "skills": [ "Pagination", "Consistency" ], "fieldMix": [ { "field": "System design", "percentage": 40 }, { "field": "Database engineering", "percentage": 30 }, { "field": "Storage systems", "percentage": 30 } ], "patterns": [] }, { "id": "f28f8ae0-c60c-4aab-9d94-f3c652da964c", "key": "AARCHIVE-108", "title": "Model retention as a policy decision separate from audit immutability", "type": "TASK", "priority": "MEDIUM", "difficulty": "EXPERT", "estimateMinutes": 300, "phaseId": "lifecycle", "dependsOn": [ "AARCHIVE-104", "AARCHIVE-106", "AARCHIVE-107" ], "scenario": "Stakeholders confuse append-only records with keeping every payload forever, while the archive has a fictional bounded retention agreement.", "acceptanceCriteria": [ "Specify retention scope, expiry and hold behavior.", "Preserve authorized deletion facts without claiming deleted bytes remain available.", "Identify which policy decisions need external approval before implementation." ], "implementationNotes": [ "Use a fictional policy and synthetic data; make no legal compliance claim." ], "verification": [ "Apply expiry to an eligible segment in the model.", "Apply a hold and show that deletion remains blocked." ], "deliverables": [ "Retention model and policy-state probe" ], "rollout": "Review policy before any delete implementation; keep proposed deletion plans read-only.", "skills": [ "Data lifecycle", "Policy modeling" ], "fieldMix": [ { "field": "Privacy engineering", "percentage": 50 }, { "field": "System design", "percentage": 30 }, { "field": "Storage systems", "percentage": 20 } ], "patterns": [] }, { "id": "01fccf7f-ffbf-4e30-81f0-b5a8a2a3a638", "key": "AARCHIVE-109", "title": "Rehearse archive restoration from manifests after index loss", "type": "TASK", "priority": "MEDIUM", "difficulty": "ADVANCED", "estimateMinutes": 240, "phaseId": "lifecycle", "dependsOn": [ "AARCHIVE-104", "AARCHIVE-105", "AARCHIVE-108" ], "scenario": "The search projection is lost, but the recovery plan assumes an index backup rather than using the authoritative archive.", "acceptanceCriteria": [ "Restore a new index generation from verified segments.", "Report corrupt or missing segments separately from indexed count.", "Keep queries from mixing partial and complete generations." ], "implementationNotes": [ "Use a small synthetic archive with one intentionally damaged segment." ], "verification": [ "Rebuild from complete manifests and compare query identities.", "Include the damaged segment and block a complete-generation claim." ], "deliverables": [ "Restoration drill and completeness report" ], "rollout": "Run the drill before archive activation; retain the old searchable generation until reconciliation succeeds.", "skills": [ "Recovery design", "Integrity verification" ], "fieldMix": [ { "field": "Storage systems", "percentage": 40 }, { "field": "System design", "percentage": 30 }, { "field": "Site reliability", "percentage": 30 } ], "patterns": [] }, { "id": "f25c2512-94f8-43b8-a337-1963aa1f5f3a", "key": "AARCHIVE-110", "title": "Prepare the archive architecture review with explicit retrieval limits", "type": "CHORE", "priority": "MEDIUM", "difficulty": "FOUNDATIONAL", "estimateMinutes": 90, "phaseId": "lifecycle", "dependsOn": [ "AARCHIVE-102", "AARCHIVE-107", "AARCHIVE-109" ], "scenario": "A roadmap summary promises unlimited search and permanent audit availability despite the bounded design.", "acceptanceCriteria": [ "Summarize workload, retention and recovery assumptions.", "Link claims to manifest, authorization and restore probes.", "List deferred infrastructure and unresolved provider capabilities." ], "implementationNotes": [ "Avoid presenting the local simulator as production storage readiness." ], "verification": [ "Trace a recent-query guarantee to its contract.", "Trace a missing-segment scenario and document the user-visible limitation." ], "deliverables": [ "Archive design review packet" ], "rollout": "Review before storage commitment; revise the packet when retention or retrieval requirements change.", "skills": [ "Architecture communication", "Evidence-based review" ], "fieldMix": [ { "field": "System design", "percentage": 70 }, { "field": "Storage systems", "percentage": 30 } ], "patterns": [] } ] } ] }