What is ai-instructions spring-boot-i18n.instructions.md?

A set of rules for managing translated messages in a Spring Boot application. It covers message keys, language-specific files, validation text, API text, documentation, and log messages.

Use it when adding validation errors, API responses, logs, or documentation that must support multiple languages.

It keeps translations organized and prevents user-facing wording from being scattered through source code. Stable keys also make it easier to add or update languages.

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Origin original No closer match found in the catalogue.

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Model	Per session	Once invoked
Fable 5.1	$0.00767	$0.00767
Opus 5.5	$0.00307	$0.00307
Sonnet 5.5	$0.00153	$0.00153
Haiku 4.5	$0.00077	$0.00077

Measured 5d ago against content hash 37c583e8f46b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

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Grade A, and why

ai-instructions spring-boot-i18n.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 5d 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.

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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-i18n.instructions.md · 78 lines

How it starts

The opening of the file, as written. The whole thing — 78 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Spring Boot i18n Contract

These rules apply to application modules that expose user-facing or log-facing message text. Projects must meet the full contract once i18n is in use.

Message bundles

Store bundles under src/main/resources/i18n/.
Ship at least:
- messages.properties as the English default bundle
- messages_pt_BR.properties for Brazilian Portuguese
Every key present in one locale file must exist in every other locale file.
Placeholder arity must match across locales for the same key (for example {0} and {1} counts must be identical).
Never hardcode user-facing API, UI, validation, or error text in Java. Resolve it through MessageSource (or a thin helper that wraps it) and a message key.
Developer-facing log text uses the dedicated logging message helper defined by the logging contract. Resolve request-scoped log messages with the request locale and messages without a request locale with the configured default locale.

Spring messages configuration

Declare all four settings in application.yml whenever the project uses message bundles:

spring:
  messages:
    basename: "i18n/messages"
    encoding: "UTF-8"
    default-locale: "en"
    fallback-to-system-locale: true

Quote string values consistently (configuration contract).
Do not let the JVM/OS locale become the fallback for missing translations.

Locale resolution

Supported locales for real projects are English and pt-BR.
Default locale is English.
REST/API applications resolve locale from the Accept-Language header. A stock AcceptHeaderLocaleResolver configured with that default and supported list is enough.
MVC/page applications may also honor an explicit lang query parameter when the UI needs a language switcher. Do not use the JVM default locale as a fallback.
Keep user-facing resolution separate from log-message resolution by using the dedicated logging helper. Both use the applicable locale: request locale for request-scoped messages and configured default locale for messages without a request.

Read the full file on GitHub · 78 lines

Changes

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5d ago Changed · -4 tokens per session 37c583e8f46b
1mo ago Changed · +3 lines · +35 tokens per session 1cf55dbd9f5c
1mo ago Changed · +3 lines · -542 tokens per session 2c78f54bb5a3
1mo ago Changed · +23 lines · +411 tokens per session 3f7d315aabcc
2mo ago First seen · 49 lines · 867 tokens per session scan A fa59146f26b8

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ai-instructions spring-boot-i18n.instructions.md is an instructions file published in the GitHub repository lsampaioweb/ai-instructions (1 stars, last pushed 5d ago), licensed MIT. It adds 767 tokens to every session, about $0.0031 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 2026-09-03.

Backend and APIs Localization

ai-instructions spring-boot-i18n.instructions.md next to 6 instructions from other repositories
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