feat: add AWS Lambda Managed Instances (LMI) skill to aws-serverless plugin by sbbhimji · Pull Request #140 · awslabs/agent-plugins

sbbhimji · 2026-04-20T21:25:36Z

Summary

Adds a new skill to help users evaluate, configure, and migrate workloads to AWS Lambda Managed Instances (LMI) — the
recently launched feature that runs Lambda functions on dedicated EC2 instances with AWS managing the lifecycle.

What's included

SKILL.md (205 lines) — core workflow with 6 steps:

Workload fitness assessment (decision table: LMI vs standard Lambda)
4-column cost comparison (Lambda OD, Lambda+SP, LMI OD, LMI+3yr SP)
Configuration recommendations (instance types, memory ratios, concurrency)
Code migration for multi-concurrency thread safety
Infrastructure setup (IAM, VPC, capacity providers)
Validation and gradual production cutover

6 reference files (42-96 lines each):

cost-comparison.md — pricing formulas, discount comparison, worked example, break-even guidance
configuration-guide.md — instance type decision tree, memory sizing from existing Lambda/EC2, concurrency tuning,
scaling controls
thread-safety.md — code review checklist, runtime-specific guidance (Node.js, Python, Java, .NET), common
anti-patterns
migration-patterns.md — before/after code examples per runtime (global state, file I/O, database connections)
infrastructure-setup.md — IAM roles, VPC requirements, CLI workflow, SAM template
troubleshooting.md — common issues, debugging steps for startup/performance/cost

Plugin registration:

Added managed-instances and lmi keywords to plugin.json
Added LMI skill triggers to README aws-serverless section
Added cross-references in aws-lambda/SKILL.md (Key Capabilities + When to Load Reference Files)

Design decisions

4-column cost comparison includes Lambda with Savings Plans (not just on-demand) since customers often already have
Compute Savings Plans covering Lambda duration
Thread safety is the critical migration gate — elevated to its own reference file with a per-runtime checklist since
this is the feat: initial branch #1 source of production issues when adopting LMI
Follows all plugin standards: SKILL.md under 300 lines, reference files under 100 lines, proper frontmatter,
progressive disclosure, explicit defaults, error handling

Test plan

Load plugin locally: claude --plugin-dir ./plugins/aws-serverless
Verify skill auto-triggers on "is LMI right for my workload?"
Verify skill auto-triggers on "migrate my Lambda to managed instances"
Verify cost comparison produces 4-column table (Lambda OD / Lambda+SP / LMI OD / LMI+SP)
Verify thread-safety checklist surfaces when reviewing function code
Verify cross-reference from aws-lambda skill routes to LMI skill
Confirm SKILL.md < 300 lines, all reference files < 100 lines
Run claude --plugin-dir ./plugins/aws-serverless --verbose to verify < 5000 token initial load

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of the project license.

…plugin Add a new skill for evaluating, configuring, and migrating workloads to AWS Lambda Managed Instances. Includes workload fitness assessment, 4-column cost comparison (Lambda OD/SP vs LMI OD/SP), configuration recommendations, thread-safety review, and end-to-end migration framework. Reference files cover cost analysis, configuration tuning, thread safety, runtime-specific migration patterns, infrastructure setup (CLI/SAM/CDK), and troubleshooting.

…nces - Add managed-instances and lmi keywords to plugin.json - Add LMI skill triggers to README aws-serverless section - Add cross-reference to LMI skill in aws-lambda SKILL.md (key capabilities and "When to Load Reference Files" sections) - Update plugin description to mention Lambda Managed Instances

Copilot

Pull request overview

Adds a new aws-lambda-managed-instances skill to the aws-serverless plugin, providing an agent workflow and reference material to evaluate, configure, and migrate workloads to Lambda Managed Instances (LMI), and wires it into existing plugin docs/metadata.

Changes:

Introduces a new aws-lambda-managed-instances skill (SKILL.md) plus several reference guides (cost, configuration, thread safety, migration patterns, infra setup, troubleshooting).
Updates the existing aws-lambda skill to cross-reference the new managed-instances skill.
Updates plugin metadata and root README to mention LMI and add trigger phrases/keywords.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
plugins/aws-serverless/skills/aws-lambda/SKILL.md	Adds cross-references so the Lambda skill routes LMI questions to the new skill.
plugins/aws-serverless/skills/aws-lambda-managed-instances/SKILL.md	New core workflow and routing to reference files for LMI evaluation/config/migration.
plugins/aws-serverless/skills/aws-lambda-managed-instances/references/cost-comparison.md	Adds pricing formulas, comparison template, and worked example for Lambda vs LMI.
plugins/aws-serverless/skills/aws-lambda-managed-instances/references/configuration-guide.md	Adds instance/memory/concurrency tuning guidance and scaling controls.
plugins/aws-serverless/skills/aws-lambda-managed-instances/references/thread-safety.md	Adds a thread-safety checklist and runtime-specific guidance.
plugins/aws-serverless/skills/aws-lambda-managed-instances/references/migration-patterns.md	Adds before/after migration examples for multi-concurrency readiness.
plugins/aws-serverless/skills/aws-lambda-managed-instances/references/infrastructure-setup.md	Adds IAM/VPC/CLI + SAM template guidance for capacity provider setup.
plugins/aws-serverless/skills/aws-lambda-managed-instances/references/troubleshooting.md	Adds common issues table and debugging steps.
plugins/aws-serverless/.claude-plugin/plugin.json	Adds `managed-instances` and `lmi` keywords for discoverability.
README.md	Updates plugin description and adds the new skill to the aws-serverless trigger table.

…model - Fix Python concurrency model: process-based isolation, no thread safety needed - Clarify cold starts claim (provisioned capacity only) - Replace hardcoded regional availability with docs link - Replace LocalStack reference with generic non-prod testing - Convert Step 5 to numbered procedure - Simplify cost comparison (defer SP/RI to pricing calculator) - Use least-privilege IAM with ec2:ManagedResourceOperator condition - Add setup-lmi.sh script for automated provisioning - Add VPC endpoint requirements table with costs - Add Powertools compatibility and SDK minimum versions - Add CloudWatch metrics dimensions guidance - Add pricing calculator, samples repo, and migration blog to resources

leandrodamascena

Hey @sbbhimji, nice work on this, the skill is well structured and the content is technically accurate. Left 2 small comments to address before merging.

…d cost example - Update Powertools .NET to supported (logging, tracing, idempotency, batch, parameters) - Remove hardcoded cost example, defer to LMI Pricing Calculator

…pricing - Strip cost-comparison.md to just pricing calculator links - Remove cost column from VPC endpoints table in infrastructure-setup.md

Merge upstream main — keep both LMI description update and new codebase-documentor-for-aws and migration-to-aws plugins.

…ces/headings/lists)

bfreiberg

Looks good to me

Signed-off-by: Alain Krok <alkrok@amazon.com>

…files - Clarify execution environments vs EC2 instances (users set MinExecutionEnvironments; Lambda manages instance count and AZ distribution) - Remove undocumented 14-day instance lifespan claim - Fix instance minimum sizes: .xlarge+ for C family, .large+ for M/R - MaxVCpuCount defaults to 400, not required - Scaling absorbs a doubling (100%), not 50% spike - Soften AZ subnet requirement to recommendation - Fix reference files: VPC endpoints only needed without NAT, subnet minimum is 1 not 3, correct policy references, fix contextvars in wrong runtime checklist

- MinExecutionEnvironments: allow 1 for non-prod, 3+ for prod - Cost threshold: use ~$1,000/month instead of 50-100M req/month - Add instance lifespan (~12h) and EE lifespan (~4h) to limits - Add /tmp usage estimation to migration checklist - Add regional availability (us-east-1/2, us-west-2, ap-northeast-1, eu-west-1)

theagenticguy

LGTM

sbbhimji added 2 commits April 20, 2026 16:16

sbbhimji requested review from a team, krokoko, scottschreckengaust and theagenticguy April 20, 2026 21:25

sbbhimji requested review from a team as code owners April 20, 2026 21:25

krokoko added 2 commits April 23, 2026 11:30

Merge branch 'main' into feature/aws-lambda-managed-instances
422c422

Merge branch 'main' into feature/aws-lambda-managed-instances
9d13eae

MichaelWalker-git requested a review from Copilot April 30, 2026 04:27

Copilotstarted reviewing on behalf of MichaelWalker-git April 30, 2026 04:28 View session

CopilotAI reviewed Apr 30, 2026
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bfreiberg requested changes May 3, 2026
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leandrodamascena suggested changes May 9, 2026
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Comment threadplugins/aws-serverless/skills/aws-lambda-managed-instances/references/thread-safety.md Outdated
Comment threadplugins/aws-serverless/skills/aws-lambda-managed-instances/references/cost-comparison.md Outdated

fix(aws-serverless): address Leandro's feedback on Powertools .NET an…
e465e5b
…d cost example - Update Powertools .NET to supported (logging, tracing, idempotency, batch, parameters) - Remove hardcoded cost example, defer to LMI Pricing Calculator

sbbhimji requested a review from bfreiberg May 10, 2026 23:05