Use it to enable virtual threads for Spring MVC applications that use blocking JDBC or HTTP calls, while retaining Spring Boot's default execution setup.

It prevents teams from adding unnecessary custom executors or changing from the familiar MVC and JDBC stack just to improve concurrency. It also keeps development and production settings consistent.

How lsampaioweb/ai-instructions configures GitHub Copilot

Q: What is ai-instructions spring-boot-virtual-threads.instructions.md?

A set of rules for enabling Java virtual threads in Spring Boot servlet applications. Virtual threads are lightweight threads that let blocking work handle more concurrent tasks without switching to a reactive programming model.

Reuse

Borrowing it

Nothing to install: this file belongs to lsampaioweb/ai-instructions. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/lsampaioweb/ai-instructions/main/.github/instructions/spring-boot-virtual-threads.instructions.md

Clone the repo

git clone --depth 1 https://github.com/lsampaioweb/ai-instructions

Made for: GitHub Copilot.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/lsampaioweb/ai-instructions/spring-boot-virtual-threads/github.svg)](https://agentmods.dev/instructions/lsampaioweb/ai-instructions/spring-boot-virtual-threads)

Your own site

<a href="https://agentmods.dev/instructions/lsampaioweb/ai-instructions/spring-boot-virtual-threads"><img src="https://agentmods.dev/badge/instructions/lsampaioweb/ai-instructions/spring-boot-virtual-threads/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/lsampaioweb/ai-instructions/spring-boot-virtual-threads"><img src="https://agentmods.dev/badge/instructions/lsampaioweb/ai-instructions/spring-boot-virtual-threads.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 375 This file is loaded in full into every session.

When invoked 375 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00375	$0.00375
Opus 5.5	$0.00150	$0.00150
Sonnet 5.5	$0.00075	$0.00075
Haiku 4.5	$0.00038	$0.00038

Measured 1mo ago against content hash d08b4cb27c65, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

ai-instructions spring-boot-virtual-threads.instructions.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.github/instructions/spring-boot-virtual-threads.instructions.md · 45 lines

What it actually says

Spring Boot Virtual Threads Contract

These rules apply to servlet/MVC applications. A deployable servlet app must meet this contract. YAML layout and profiles stay in the configuration contract. Outbound RestClient setup stays in the HTTP-client contract.

Enablement

Enable virtual threads in shared application.yml (not only in one profile):
```
spring:
  threads:
    virtual:
      enabled: true
```
Keep the same value for development and production. Do not disable virtual threads in production as a default.

Runtime model

Keep the blocking servlet stack: MVC, JDBC, and RestClient.
Do not switch the application to WebFlux to get concurrency.
Do not add a custom TaskExecutor, VirtualThreadTaskExecutor, or Executors.newVirtualThreadPerTaskExecutor() bean unless the product needs a named executor beyond Spring Boot's default.
Do not lower server.tomcat.threads.max as a virtual-thread trick unless you are measuring a specific experiment.

Forbidden

Never omit spring.threads.virtual.enabled: true from a real servlet/MVC app.
Never place that flag only in application-development.yml or only in application-production.yml.
Never introduce WebFlux solely to handle blocking I/O concurrency.
Never add a custom virtual-thread executor as the application's default request concurrency mechanism.
Never require a Tomcat max thread override to "enable" virtual threads.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

1mo ago First seen · 45 lines · 375 tokens per session scan A d08b4cb27c65

Subscribe to this mod's changes

ai-instructions spring-boot-virtual-threads.instructions.md is an instructions file published in the GitHub repository lsampaioweb/ai-instructions (1 stars, last pushed 5d ago), licensed MIT. It adds 375 tokens to every session, about $0.0015 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-30.

Backend and APIs

ai-instructions spring-boot-virtual-threads.instructions.md next to 6 instructions from other repositories
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