Condense AGENTS.md with key build, architecture, and style guidelines

Amp-Thread-ID: https://ampcode.com/threads/T-019c3409-53a5-7763-ab89-564c189dc191
Co-authored-by: Amp <amp@ampcode.com>

Author: LarsEckart

AGENTS.md

@@ -1,49 +1,20 @@
 # ApprovalTests.Java Agent Instructions
 
-## Project Overview
-
-ApprovalTests.Java is a snapshot-based testing library that simplifies assertions by comparing expected output to approved files. The library supports JUnit 3/4/5 and TestNG, and works with JDK 1.8-25.
+## Build & Test
+- **Full build:** `./build_and_test` (takes 1-2 min; auto-formats code via Maven formatter plugin)
+- **Single test:** `mvn test -pl approvaltests-tests -Dtest=ClassName#methodName`
+- Tests run with `en_US` locale (surefire config). Java target is 1.8.
 
 ## Architecture
+Multi-module Maven project: **approvaltests** (core library), **approvaltests-util** (shared utilities), **approvaltests-tests** and **approvaltests-util-tests** (tests). Core API: `org.approvaltests.Approvals` with `verify()`, `verifyAll()`, `verifyAsJson()`. Pattern: Writers (generate output) → Namers (file naming) → Reporters (show diffs on failure).
 
-This is a multi-module Maven project with the following key modules:
-
-- **approvaltests**: Main library containing core functionality (`Approvals.java`, writers, reporters, namers)
-- **approvaltests-util**: Shared utilities and helper classes (used as a dependency by approvaltests)
-- **approvaltests-tests**: Integration tests and examples
-- **approvaltests-util-tests**: Tests for utility classes
-- **counter_display**: Sample application
-- **html_locker**: Additional tooling
-
-The core API is in `org.approvaltests.Approvals` class, which provides static methods like `verify()`, `verifyAll()`, `verifyAsJson()`. The library uses a pattern of Writers (generate output), Namers (determine file names), and Reporters (show differences when tests fail).
-
-## Common Commands
-
-### Build and Test
-```bash
-# Build and test via Mise (requires mise installed)
-./build_and_test
-```
-
-**Note:** The project uses [Mise](https://mise.jdx.dev/) for task automation. The `.mise.toml` file defines tasks like `build_and_test` and `format`. Java version is specified in `.java-version` file.
-
-## Key Files and Concepts
-
-- **Approved files**: `*.approved.*` files must be committed to source control. These are automatically treated as binary in git via `.gitattributes` (`*.approved.* binary diff`)
-- **Received files**: `*.received.*` files generated during test failures, showing actual output vs approved. These should not be committed
-- **Reporters**: Tools that show diffs when tests fail (IntelliJ, Beyond Compare, etc.). Located in `org.approvaltests.reporters`
-- **Namers**: Determine approval file naming based on test method/class. Located in `org.approvaltests.namer`
-- **Writers**: Generate the actual content to be approved. Located in `org.approvaltests.writers`
-
-## Running Single Tests
-
-Individual test methods can be run using standard Maven/IDE approaches:
-```bash
-mvn test -Dtest=ClassName#methodName
-```
-
-**Note:** Tests run with `en_US` locale by default (configured in surefire plugin) to ensure consistent output across different environments.
+## Key Rules
+- **NEVER** approve a test (update `.approved.*` files) automatically — always prompt the user. Commit `.approved.*` files; never commit `.received.*` files.
+- Make file changes directly without asking permission (repo is under git, user can revert).
+- The build auto-formats code — do not worry about formatting.
 
 ## Code Style
-
-There is an automatic code formatter that is used every time you build the project.
+- Allman brace style (opening brace on new line). camelCase methods, PascalCase classes.
+- Uses custom `org.lambda` utilities over Java Streams in core code.
+- Heavy use of `public static` overloaded methods for the main API.
+- Do not add unnecessary comments. Follow existing patterns in neighboring files.