damusix/skills

arm-bandits-expert

Implements, evaluates, and deploys multi-armed bandit algorithms — including Thompson Sampling, UCB, epsilon-greedy, LinUCB, EXP3, and contextual bandits. Covers algorithm selection, experiment harnesses, offline evaluation (IPS, Doubly Robust), infrastructure patterns, and correctness verification. Use when the user asks about multi-armed bandits, exploration-exploitation tradeoffs, adaptive experiments, A/B testing alternatives, online optimization, bandit-based recommendation or personalizat…

First seen Mar 30, 2026

Installation

$ npx skills add damusix/skills --skill arm-bandits-expert

Summary

  • Implements, evaluates, and deploys multi-armed bandit algorithms — including Thompson Sampling, UCB, epsilon-greedy, LinUCB, EXP3, and contextual bandits.
  • Covers algorithm selection, experiment harnesses, offline evaluation (IPS, Doubly Robust), infrastructure patterns, and correctness verification.
  • Use when the user asks about multi-armed bandits, exploration-exploitation tradeoffs, adaptive experiments, A/B testing alternatives, online optimization, bandit-based recommendation or personalization systems, or contextual bandits.

Similar popular skills

Related neighbors and high-traction skills in the same topics — useful to compare before installing.

Also in this package

Other skills from damusix/skills · top by installs.

npx skills add damusix/skills

Browse all from damusix/skills

More details

Agent compatibility

Declared targets from SKILL.md / docs. Unmarked agents are not listed — the skill may still install via the CLI.

Claude Code Not declared
Cursor Not declared
Codex Not declared
GitHub Copilot Not declared
Windsurf Not declared
Gemini CLI Not declared
Cline Not declared
OpenCode Not declared

Repository health

Stars 63
Default branch main
Open issues 0
Status Active

Package contents

Files included with this skill beyond the listing page.

  • skill md SKILL.md 5,740 B
  • docs SUMMARY.md 562 B

History

  1. First seen on skills.sh
  2. First recorded snapshot · 8 installs

SKILL.md

Multi-Armed Bandits Expert

Guide the user based on their actual need. Do not lecture; respond to what they're doing.

Routing

Assess the user's situation and route to the appropriate reference material. Read the relevant file(s) from skill/references/ before responding.

Entry Paths

"I need to learn about bandits" → Start with tier-1-core-algorithms.md. Progress to tier 2/3 only when the user is ready or asks.

"I need to pick an algorithm" → Use the decision framework below, then read the relevant tier reference for details.

"I need to build/evaluate an experiment" → Read experiment-harness-patterns.md for environment, policy, runner, and offline evaluation abstractions.

"I need to review/debug an implementation" → Read infrastructure-patterns.md for testing patterns and bug checklists. Cross-reference the relevant algorithm tier for formula verification.

"I need to deploy to production" → Read infrastructure-patterns.md for serving, reward pipelines, monitoring, and safety guardrails.

"I need to understand the business case" → Read business-applications.md for domain-specific guidance, real-world examples, and ROI evidence from 60+ named company deployments.

Decision Framework — Picking an Algorithm

Present trade-offs. Never prescribe a single "best" algorithm without context.

Step 0: Does the user specify an algorithm?

If the task names a specific algorithm (e.g. "implement UCB1", "use epsilon-greedy"), implement that algorithm — do not substitute a different one. Only use this decision framework when the user asks for help choosing an algorithm or says something generic like "implement a bandit."

Step 1: What kind of rewards?

Reward type Candidates
Binary (click/no-click) UCB1 is the classical default; Thompson Sampling (Beta-Bernoulli) for best empirical performance; epsilon-greedy for simplicity
Continuous (revenue, time) UCB1, Thompson Sampling (Gaussian/NIG), LinUCB
Adversarial / non-stationary EXP3, SW-UCB, D-UCB, change-point detectors

Step 2: Do you have context features?

Context Candidates
No context Epsilon-greedy, UCB1, Thompson Sampling, Softmax
User/item features available LinUCB, contextual Thompson Sampling
High-dimensional features Neural bandits (NeuralUCB/NeuralTS, last-layer Bayesian)

Step 3: What's your constraint?

Constraint Recommendation
Simplest possible baseline Epsilon-greedy with decay
Strongest theoretical guarantees UCB1 (stochastic), EXP3 (adversarial)
Best empirical performance Thompson Sampling
Delayed feedback Thompson Sampling (robust to stale posteriors)
Multiple items per round Combinatorial bandits (CUCB + oracle)
Ranked lists with position bias Cascading bandits (CascadeUCB1, CascadeLinTS)
Arms change state over time Restless bandits (Whittle index)
Reward distributions shift Non-stationary bandits (SW-UCB, GLR-UCB)

Step 4: Maturity reality check

Algorithm Maturity Production examples
Epsilon-greedy Battle-tested Optimizely, Kameleoon
UCB1 Battle-tested Widespread
Thompson Sampling Battle-tested Yahoo, Stitch Fix, Doordash
LinUCB Production-proven Yahoo News, Netflix, Spotify
EXP3 Well-established Adversarial settings
Bayesian UCB Production-proven River, MABWiser
Softmax Battle-tested Deep RL action selection
Neural bandits Early production Meta ENR (9%+ CTR lift)
Non-stationary (SW/D/GLR-UCB) Well-established SMPyBandits, monitoring
Combinatorial bandits Research Ad placement (Chen et al.)
Restless bandits Research → applied Health interventions (Armman)
Cascading bandits Early production Expedia homepage ranking

Build Phases

  1. Core Library — Implement algorithms starting with tier 1 (epsilon-greedy or Thompson Sampling). See tier-1-core-algorithms.md through tier-3-production-algorithms.md.
  2. Experiment Harness — Build environment, runner, and metrics to compare algorithms offline. See experiment-harness-patterns.md.
  3. Production Infrastructure — Add reward pipelines, serving, monitoring, safety guardrails. See infrastructure-patterns.md.

Reference Files

File Contents
references/tier-1-core-algorithms.md Epsilon-greedy, UCB1, Thompson Sampling — pseudocode, properties, pitfalls
references/tier-2-practical-algorithms.md LinUCB, EXP3, Bayesian UCB, Softmax — context handling, adversarial robustness
references/tier-3-production-algorithms.md Neural, combinatorial, non-stationary, restless, cascading bandits
references/experiment-harness-patterns.md Environment, policy, runner abstractions, metrics, offline evaluation
references/infrastructure-patterns.md Project structure, testing, reward pipelines, serving, monitoring, safety
references/business-applications.md Business decision framework, domain guides, algorithm-to-problem mapping, ROI evidence, failure modes