s3-mcp-server-java AGENTS.md

Project instructions for a Java server that connects an MCP service to Amazon S3, an online storage system for files and other data.

In plain words
What is it for?
Use it when building, testing, organizing, or running this Java S3 server, including its unit and integration tests.
Why use it?
It gives developers the repository structure, commands, coding rules, and testing requirements needed to change the project consistently.

Instructions file for CodexOpenCode

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add instructions/alexwangda/s3-mcp-server-java/agents-md
Clone the repo
git clone --depth 1 https://github.com/AlexWangDa/s3-mcp-server-java

Made for: Codex, OpenCode.

Per session 560 This file is loaded in full into every session.
When invoked 560 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00560 $0.00560
Opus 5 $0.00280 $0.00280
Sonnet 5 $0.00112 $0.00112
Haiku 4.5 $0.00056 $0.00056

Measured 2d ago against content hash d45222b4dadc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

s3-mcp-server-java AGENTS.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 2d 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.

AGENTS.md · 33 lines

How it starts

The opening of the file, as written. The whole thing — 33 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Repository Guidelines

Project Structure & Module Organization

Production code lives under src/main/java/org/springframework/ai/mcp/sample/server. Keep AWS client setup in config, access and path checks in security, tool behavior in service, and AWS-independent response records in entity. Runtime settings and stderr logging are in src/main/resources. Tests mirror those packages under src/test/java; MinIO and packaged-STDIO coverage belongs in integration. Design decisions and implementation plans are recorded in docs/superpowers.

Build, Test, and Development Commands

Use the checked-in Maven Wrapper so local and CI builds use the same Maven version.

  • ./mvnw clean package builds the executable JAR in target/.
  • ./mvnw -B test runs the fast unit-test suite.
  • ./mvnw -B clean verify runs all checks, including Failsafe integration tests; Docker is required for Testcontainers.
  • ./mvnw -B -Dtest=S3ServiceReadTest test runs one test class while iterating.

Run the packaged server with java -jar target/s3-mcp-server-0.2.0-SNAPSHOT.jar --s3.region=us-east-1. Keep stdout reserved for MCP traffic.

Coding Style & Naming Conventions

Target Java 17 and indent Java with four spaces. Prefer constructor injection, immutable records, focused methods, and existing Spring conventions. Use UpperCamelCase for types, lowerCamelCase for methods and fields, and UPPER_SNAKE_CASE for constants. Name unit tests *Test and integration tests *IT. No formatter or linter is enforced, so match surrounding imports and whitespace.

Testing Guidelines

Use JUnit 5, AssertJ, and Mockito for isolated behavior. Use Testcontainers with the shared MinIO fixture for S3 compatibility tests. Cover success, policy rejection, error translation, and side effects; security fixes need a regression test. Run clean verify before submitting changes.

Commit & Pull Request Guidelines

Follow the repository's Conventional Commit style, for example feat: add bucket filter or docs: clarify MinIO setup. Keep commits scoped. Pull requests should explain behavior and security impact, link related issues, list verification commands and results, and update README/config examples when interfaces change. Attach screenshots only when a visual change exists.

Read the full file on GitHub · 33 lines

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.

  1. 2d ago First seen · 33 lines · 560 tokens per session scan A d45222b4dadc

Subscribe to this mod's changes

s3-mcp-server-java AGENTS.md is an instructions file published in the GitHub repository AlexWangDa/s3-mcp-server-java (8 stars, last pushed 6d ago), licensed Apache-2.0. It adds 560 tokens to every session, about $0.0028 per session on Opus 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 2026-08-31.

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