IMPLEMENT WHAT YOU LEARN

Coding labs

A focused problem, a blank function, and tests that tell you what broke.

Python runs in your browser. No API key. No setup. 32 module challenges and 50 extension exercises, with hints and explained reference solutions.

82 challenges

CHALLENGEDIFFICULTYTIMESTATUS

Validate and normalize a batch requestPython at the system boundary

Foundation50 minSolve

Implement threshold evaluation with explicit edge casesThe mathematics of useful predictions

Foundation55 minSolve

Implement one masked attention queryNeural computation from first principles

Intermediate65 minSolve

Plan cache capacity for variable-length requestsInside a modern language model

Intermediate55 minSolve

Fold a stream without inventing completionIntegrating models without losing control

Intermediate60 minSolve

Replay a bounded agent lifecycleYour first bounded agent service

Intermediate70 minSolve

Implement a scoped idempotent inventory operationTool contracts that survive real requests

Intermediate60 minSolve

Build a versioned, policy-checked call envelopeMCP integration with explicit version and trust boundaries

Intermediate60 minSolve

Validate and schedule an observable planObservable planning and evidence-driven revision

Intermediate65 minSolve

Implement a validated strategy selectorCognitive architecture as an inspectable control system

Intermediate60 minSolve

Select current scoped memories under a budgetMemory with scope, provenance, and a lifecycle

Intermediate70 minSolve

Fuse filtered retrieval rankings deterministicallyRetrieval that preserves the evidence needed to answer

Intermediate60 minSolve

Find a temporally coherent evidence pathAdvanced RAG with graphs, time, and evaluation

Advanced75 minSolve

Compute deterministic ready batchesCollaboration with explicit dependencies

Intermediate45 minSolve

Select a unique target from a semantic snapshotBrowser agents with verifiable outcomes

Intermediate45 minSolve

Join speech intervals to screen framesDesktop perception and multimodal alignment

Intermediate45 minSolve

Reduce interrupted audio playback eventsChannels, webhooks, and interruptible voice

Intermediate45 minSolve

Advance a task with optimistic revision checksA2A collaboration across service boundaries

Intermediate45 minSolve

Apply a constrained atomic state patchGenerated interfaces and streaming interaction

Advanced50 minSolve

Count distinct events in a half-open windowEvent-driven and proactive agents

Intermediate45 minSolve

Build a deadline-aware retry simulatorRecovery without duplicate actions

Advanced60 minSolve

Evaluate scoped grants and exact action approvalsPermissions and containment for agent actions

Advanced70 minSolve

Reconcile a deduplicated token-cost ledgerAgent economics and observable performance

Advanced60 minSolve

Compute an exact paired binary comparisonEvaluations that support engineering decisions

Advanced65 minSolve

Select impacted tests through reverse dependenciesCoding agents that can justify their patches

Advanced60 minSolve

Enforce lease ownership with fencing tokensProduction agents as recoverable distributed services

Advanced70 minSolve

Build a group-safe dataset gateTraining data and efficient adaptation

Advanced60 minSolve

Audit a logged policy with importance weightsLearning from rewards and preferences

Advanced65 minSolve

Implement page-aware cache admissionInference performance and capacity engineering

Advanced60 minSolve

Enforce a trusted access decisionPrivacy, adversarial evaluation, and operating boundaries

Advanced60 minSolve

Compute a paired comparison with an exact sign-flip testResearch methods for agent systems

Advanced70 minSolve

Reduce replayed task events without duplicate accountingIntegrated agent systems and capstone evidence

Advanced75 minSolve

Summarize validated run recordsPython at the system boundary

Foundation50 minSolve

Bound asynchronous work and preserve orderingPython at the system boundary

Intermediate65 minSolve

Verify a batch gradient updateNeural computation from first principles

Intermediate65 minSolve

Implement a causal attention headNeural computation from first principles

Intermediate65 minSolve

Apply ordered subword mergesInside a modern language model

Intermediate65 minSolve

Compute masked next-token lossInside a modern language model

Foundation50 minSolve

Execute only a typed arithmetic toolYour first bounded agent service

Foundation50 minSolve

Stop a scripted agent with evidenceYour first bounded agent service

Intermediate65 minSolve

Collect an opaque-cursor tool catalogMCP integration with explicit version and trust boundaries

Intermediate65 minSolve

Correlate and classify invocation resultsMCP integration with explicit version and trust boundaries

Intermediate65 minSolve

Find ready steps in a validated planObservable planning and evidence-driven revision

Intermediate65 minSolve

Check claims against fresh evidenceObservable planning and evidence-driven revision

Intermediate65 minSolve

Retrieve scoped and fresh memoriesCognitive architecture as an inspectable control system

Intermediate65 minSolve

Choose a feasible positive-value actionCognitive architecture as an inspectable control system

Intermediate65 minSolve

Select scoped memory recordsMemory with scope, provenance, and a lifecycle

Intermediate50 minSolve

Fuse candidate rankingsRetrieval that preserves the evidence needed to answer

Intermediate50 minSolve

Schedule a bounded DAGCollaboration with explicit dependencies

Intermediate50 minSolve

Invalidate stale checkpointsCollaboration with explicit dependencies

Intermediate50 minSolve

Resolve an actionable semantic targetBrowser agents with verifiable outcomes

Intermediate50 minSolve

Detect evidence dependence and conflictBrowser agents with verifiable outcomes

Intermediate50 minSolve

Map a screenshot targetDesktop perception and multimodal alignment

Intermediate50 minSolve

Apply and reverse a versioned editDesktop perception and multimodal alignment

Intermediate50 minSolve

Route verified channel eventsChannels, webhooks, and interruptible voice

Intermediate50 minSolve

Verify and deduplicate signed bytesChannels, webhooks, and interruptible voice

Intermediate50 minSolve

Parse a strict arithmetic requestPermissions and containment for agent actions

Intermediate50 minSolve

Advance a circuit breakerRecovery without duplicate actions

Intermediate50 minSolve

Select a compatible advertised interfaceA2A collaboration across service boundaries

Intermediate65 minSolve

Reduce an interrupted task logA2A collaboration across service boundaries

Intermediate65 minSolve

Validate a bounded UI snapshotGenerated interfaces and streaming interaction

Intermediate65 minSolve

Assemble interleaved message eventsGenerated interfaces and streaming interaction

Intermediate65 minSolve

Select a route under hard constraintsAgent economics and observable performance

Intermediate65 minSolve

Reserve and settle a shared budgetAgent economics and observable performance

Intermediate65 minSolve

Apply repeated events exactly once locallyEvent-driven and proactive agents

Intermediate65 minSolve

Aggregate with an explicit lateness policyEvent-driven and proactive agents

Intermediate65 minSolve

Build a lexical repository symbol indexCoding agents that can justify their patches

Intermediate65 minSolve

Apply a bounded patch atomically in memoryCoding agents that can justify their patches

Intermediate65 minSolve

Report evaluation coverage and outcomesEvaluations that support engineering decisions

Intermediate65 minSolve

Bootstrap a paired candidate differenceEvaluations that support engineering decisions

Intermediate65 minSolve

Reconcile a reconnecting task feedIntegrated agent systems and capstone evidence

Intermediate40 minSolve

Measure overlap without double countingProduction agents as recoverable distributed services

Intermediate45 minSolve

Compute a milestone critical pathIntegrated agent systems and capstone evidence

Intermediate45 minSolve

Compare complete paired runsResearch methods for agent systems

Intermediate45 minSolve

Resolve unique provenance sourcesAdvanced RAG with graphs, time, and evaluation

Intermediate45 minSolve

Query state with two time cutoffsAdvanced RAG with graphs, time, and evaluation

Intermediate45 minSolve

Compute a dimension-safe LoRA forward passTraining data and efficient adaptation

Intermediate45 minSolve

Build a symmetric quantizerInference performance and capacity engineering

Intermediate40 minSolve

Enforce a scoped action grantPrivacy, adversarial evaluation, and operating boundaries

Intermediate45 minSolve

Score adversarial effects and benign utilityPrivacy, adversarial evaluation, and operating boundaries

Intermediate40 minSolve

Measure probability quality and calibration binsProduction agents as recoverable distributed services

Intermediate50 minSolve

Standardize a comparison across case mixResearch methods for agent systems

Intermediate50 minSolve

Lab checks are practice feedback, not a secure certification. Run the downloadable exercises locally if your browser limits WebAssembly.