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Anthropic·Software Engineer·Online Assessment (OA)·Intermediate

Intermediate
May 2026

Summary

Got an OA for a Software Engineer role at Anthropic about a week after applying. It was a multi-level task management system design problem, the kind where each level stacks complexity on top of the last. Submitted partway through the second week of the recommended window.

Questions Asked (4)

Q1

Design and implement a basic task management system with standard create, read, update, and delete operations.

System DesignAPI & Integrations
Author's notes

Straightforward enough to start.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and scope, then outline a high-level design covering data model, API endpoints, and storage before diving into implementation details. Focus on clean CRUD operations, error handling, and scalability considerations, and be prepared to write pseudocode or actual code for key parts.

Pro tip: Demonstrate production-readiness by discussing idempotency, pagination, and concurrency control early, and mention how you would test and monitor the system. This shows you think beyond basic functionality.

1. Clarify Requirements

Ask about expected scale, user roles, task attributes, and non-functional requirements like latency and consistency. This ensures you design the right system.

2. Design Data Model and API

Define the Task entity with fields like id, title, description, status, due date, and timestamps. Specify RESTful endpoints for CRUD operations (e.g., POST /tasks, GET /tasks/{id}, PUT /tasks/{id}, DELETE /tasks/{id}).

3. Choose Storage and Architecture

Select a database (SQL or NoSQL) based on requirements, and outline a simple layered architecture (e.g., controller, service, repository). Discuss trade-offs.

4. Implement Core Logic

Write pseudocode or actual code for key operations, handling validation, error cases (e.g., not found, invalid input), and returning appropriate HTTP status codes.

5. Address Scalability and Reliability

Discuss pagination, filtering, rate limiting, idempotency, concurrency control (e.g., optimistic locking), and how to test and monitor the system.

Key Points to Mention

  • RESTful API design principles and proper use of HTTP methods and status codes
  • Data validation and error handling for robust CRUD operations
  • Database choice (SQL vs NoSQL) and schema design considerations
  • Pagination, filtering, and sorting for read operations
  • Concurrency control (e.g., optimistic locking) to handle simultaneous updates
  • Testing strategies (unit, integration) and monitoring for production readiness

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q2

Extend the task management system to support sorting tasks by priority and by creation order.

Algorithms & Data StructuresTechnical Trade-offs
Author's notes

Had to think about whether to sort at insertion or at query time.

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AI HintsAI Generated

Suggested Approach

Clarify the requirements first: what does 'priority' mean (e.g., high/medium/low or numeric), and whether creation order is ascending or descending. Then propose a design that supports both sort orders efficiently, discussing data structures and trade-offs between simplicity and performance.

Pro tip: Mention that you can maintain two sorted views or use a comparator-based approach, and highlight that the choice depends on read/write patterns and whether tasks are frequently added or re-prioritized.

1. Clarify requirements

Ask about the definition of priority (e.g., numeric scale, enum), whether sorting should be stable, and if both ascending and descending orders are needed. Also confirm if tasks can be updated or deleted.

2. Choose data structures

Consider options like maintaining a list and sorting on demand, using a balanced BST or skip list for dynamic order, or keeping two separate sorted structures (e.g., one by priority, one by creation time). Discuss trade-offs in time/space complexity.

3. Design the API

Define methods like getTasksSortedByPriority() and getTasksSortedByCreationOrder(). Ensure the interface is clean and extensible for future sort criteria.

4. Handle updates and concurrency

Explain how to maintain sorted order when tasks are added, removed, or have their priority changed. If multithreaded, discuss synchronization or lock-free approaches.

5. Analyze trade-offs

Compare the proposed solution with alternatives in terms of time complexity for insertion, deletion, and retrieval, as well as memory overhead and code complexity.

Key Points to Mention

  • Comparator-based sorting (e.g., using a custom comparator for priority and creation timestamp)
  • Stable sorting to preserve creation order when priorities are equal
  • Time complexity: O(n log n) for sorting on demand vs O(log n) insertion for balanced BST
  • Space-time trade-off: maintaining multiple sorted structures vs sorting on demand
  • Handling dynamic updates (e.g., priority changes) efficiently
  • Extensibility for future sort criteria (e.g., due date, status)

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q3

Add user quota enforcement and the ability to assign tasks to specific users.

System DesignData ModelingTechnical Trade-offs
Author's notes

This is where things got interesting.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and scale, then design a data model that supports quotas and task assignments. Discuss trade-offs between enforcement strategies (e.g., synchronous vs. asynchronous) and how to handle edge cases like quota exhaustion or reassignment.

Pro tip: Proactively address how you would handle quota enforcement in a distributed system, including idempotency and race conditions, to show depth beyond basic CRUD.

1. Clarify Requirements

Ask questions to understand the scope: What defines a user? What are the quota limits (per user, per task type)? How are tasks assigned (manual, automatic)? What happens when quota is exceeded?

2. Design Data Model

Propose schemas for users, quotas, and tasks. Consider fields like user_id, quota_limit, quota_used, task_id, assignee_id, and status. Discuss normalization vs. denormalization for performance.

3. Enforcement Mechanism

Decide where and how to enforce quotas: at API gateway, service layer, or database. Discuss synchronous checks vs. asynchronous reconciliation, and how to handle concurrency (e.g., atomic increments, distributed locks).

4. Task Assignment Logic

Define how tasks are assigned to users: manual assignment, round-robin, or based on user capacity. Ensure assignment respects quotas and handles reassignment or unassignment.

5. Trade-offs and Scalability

Discuss trade-offs: strict enforcement vs. eventual consistency, performance impact, and scalability. Mention monitoring, alerting, and how to handle quota resets (e.g., daily/monthly).

Key Points to Mention

  • Quota enforcement strategies: pre-check vs. post-check, and their impact on user experience.
  • Data consistency: using transactions or atomic operations to avoid race conditions in quota updates.
  • Task assignment models: manual vs. automatic, and how to handle reassignment when quotas change.
  • Scalability considerations: sharding by user_id, caching quota counts, and asynchronous processing.
  • Error handling: what happens when quota is exceeded (e.g., reject task, queue, or notify).
  • Monitoring and analytics: tracking quota usage and task assignment metrics for insights.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q4

Support historical queries on the task management system, allowing lookups of past task states or activity.

Data ModelingSystem Design
Author's notes

Ran short on time here.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the requirements: what historical data is needed (task states, activity logs), query patterns (point-in-time lookups, range queries), and retention/performance constraints. Then propose a data model that captures immutable events or versioned records, and discuss storage and indexing strategies to support efficient historical queries.

Pro tip: Emphasize that historical data is append-only and immutable, which simplifies consistency and enables auditability. Also, consider using a hybrid approach: keep current state in a mutable store for fast access, and historical data in an immutable log or versioned table for queries.

1. Clarify Requirements

Ask about the types of historical queries (e.g., point-in-time task state, activity feed), required latency, retention period, and expected query volume.

2. Choose Data Model

Decide between event sourcing (store all events) or versioning (store each version of a task). Consider a hybrid: current state table plus history table.

3. Design Storage & Indexing

Select appropriate storage (e.g., relational with temporal tables, NoSQL with time-series, or append-only log). Plan indexes on task ID and timestamp for efficient lookups.

4. Address Query Patterns

Implement queries for point-in-time (e.g., state at timestamp) and range (e.g., all changes in a period). Use efficient techniques like snapshotting or event replay.

5. Discuss Trade-offs & Scalability

Compare approaches in terms of write/read performance, storage cost, complexity, and scalability. Mention partitioning, archiving, and caching strategies.

Key Points to Mention

  • Event sourcing vs. versioning for capturing historical state
  • Temporal database features (e.g., system-versioned tables in SQL:2011)
  • Indexing strategies: composite indexes on (task_id, timestamp)
  • Query patterns: point-in-time, range, and activity feed queries
  • Data retention and archiving policies to manage storage growth
  • Trade-offs: write amplification, read latency, and complexity

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.