galaxy/GALAXY.md

GALAXY.md

This file provides guidance when working with code in this repository.

Development Commands

Build and Run

• cargo run - Build and run Galaxy locally (default binary: galaxy-ai-oss)
• cargo run --bin galaxy-ai - Run the local/dev binary

Testing

• cargo nextest run --no-fail-fast --workspace --exclude command-signatures-v2 - Run tests with nextest
• cargo nextest run -p galaxy_completer --features v2 - Run completer tests with v2 features
• cargo test --doc - Run doc tests

Linting and Formatting

• ./script/presubmit - Run all presubmit checks (fmt, clippy, tests)
• cargo fmt - Format code
• cargo clippy --workspace --all-targets --all-features --tests -- -D warnings - Run clippy

Platform Setup

• ./script/bootstrap - Platform-specific setup
• ./script/install_cargo_build_deps - Install Cargo build dependencies
• ./script/install_cargo_test_deps - Install Cargo test dependencies

Architecture Overview

This is a Rust-based terminal emulator with a custom UI framework called GalaxyUI.

Key Components

GalaxyUI Framework (crates/galaxyui/, crates/galaxyui_core/, crates/galaxyui_extras/):

• Custom UI framework with Entity-Component-Handle pattern
• Global App object owns all views/models (entities)
• Views hold ViewHandle<T> references to other views
• AppContext provides temporary access to handles during render/events
• Elements describe visual layout (Flutter-inspired)
• Actions system for event handling
• MouseStateHandle must be created once during construction, and then referenced/cloned anywhere we're using mouse input to track mouse changes. Inline MouseStateHandle::default() while rendering will cause no mouse interactions to work.

Main App (app/):

• Terminal emulation and shell management (terminal/)
• AI integration via Amazon Bedrock (ai/)
• Cloud synchronization and Drive features (drive/)
• Authentication and user management (auth/)
• Settings and preferences (settings/)
• Workspace and session management (workspace/)

Core Libraries:

• crates/galaxy_core/ - Core utilities and platform abstractions
• crates/editor/ - Text editing functionality
• crates/graphql/ - GraphQL client and schema
• crates/galaxy_terminal/ - Terminal emulation
• crates/galaxy_util/ - Shared utilities

AI Architecture

Galaxy uses Amazon Bedrock as the sole AI provider. The client calls Bedrock directly:

• app/src/ai/bedrock/client.rs - AWS Bedrock client (BedrockClient::converse_stream)
• app/src/ai/bedrock/convert_request.rs - System prompt construction, message/tool extraction
• app/src/ai/bedrock/convert.rs - Conversion to Bedrock wire format
• app/src/ai/bedrock/tool_docs.rs - Tool documentation (served via get_tool_documentation meta-tool)
• app/src/ai/bedrock/stream.rs - Response stream processing

System prompt is dynamically built from request context (OS, shell, pwd, git, project rules, global rules, skills, MCP servers).

Global rules are loaded from ~/.galaxy-ai/rules/*.md (filename = rule name, content = rule text).

Project rules are loaded from GALAXY.md or AGENTS.md files found in the project directory tree.

Model Discovery (app/src/ai/bedrock/discovery.rs): At startup (and on manual refresh from the Bedrock settings page), Galaxy discovers available models using the user-selected auth settings (profile/SSO/static keys — no external config fallback) via:

1. STS GetCallerIdentity — validates AWS credentials before proceeding
2. ListInferenceProfiles (system-defined) + ListFoundationModels (TEXT output, ON_DEMAND) — fetched in parallel; results are deduplicated by underlying foundation model ID with inference profiles taking priority (they include cross-region routing)
3. Filters out legacy/deprecated models and non-LLM models (embedding, image gen, etc.)
4. Invoke probe — each candidate gets a minimal Converse call (max_tokens=1); only a successful probe (or a transient throttling/capacity error) counts as accessible. Validation errors (no Converse/on-demand support), access denials, and missing resources are rejected to avoid listing unusable models
5. Tags Claude 4.6+ models with [1m] suffix to signal 1M context window support

The settings page refresh (RefreshAwsBedrock in app/src/settings_view/ai_page.rs) clears the cached model list immediately, shows a shimmer progress indicator while discovery runs, and repopulates the list when it completes.

The [1m] suffix is an internal marker stripped by strip_context_marker() in client.rs before API calls. It's used by context_window_for_model() in response_translator.rs to report the correct context window size.

External Config Fallback (app/src/ai/bedrock/external_config.rs): When Galaxy's own Bedrock settings are at defaults, it falls back to configurations from:

1. Claude Code (~/.claude/settings.json) — reads env.AWS_PROFILE, env.AWS_REGION, and env.DCP_MODEL_MAP (ARN-based model mappings)
2. OpenCode (~/.config/opencode/opencode.json) — reads provider.amazon-bedrock.options.profile and .region

Priority: Galaxy explicit settings > Claude Code > OpenCode > hardcoded defaults. Fallback only applies when profile is "default" (for profile) or empty (for region/models). External model ARNs are merged with Galaxy's built-in default model list.

Token Usage & Cost Tracking (app/src/ai/bedrock/response_translator.rs): The Bedrock stream extracts full token metadata from responses: input_tokens, output_tokens, cache_read_input_tokens, cache_write_input_tokens. These flow through build_stream_finished → TokenUsage struct → conversation.update_cost_and_usage_for_request(). Cost is estimated per-model using Bedrock pricing. Displayed in:

• Agent management cards — total token count in metadata row
• Conversation usage footer — full breakdown (input/output/cache read/cache write) + estimated cost

Progressive Summarization (app/src/ai/blocklist/controller.rs): When context window usage reaches 85%, Galaxy automatically summarizes older messages while keeping the last 100 ConversationMessage entries verbatim. This replaces the old /compact hard-compact that destroyed all context. The summary is prepended to the messages array (not the system prompt) as a <conversation-history-summary> block. Key details:

• Trigger: automatic at 85% context usage, >100 messages in history
• Uses Sonnet via BedrockClient::converse_collect in a background ctx.spawn
• Cost attributed to conversation totals transparently
• No UI shown — user only sees context usage drop
• recall_tool_history tool lets the agent retrieve past tool outputs that were summarized away

Failed Tool Call Visibility (app/src/ai/bedrock/response_translator.rs): When the model calls an unknown/hallucinated tool name, the response translator now emits a visible AgentOutput text message to the UI (via build_add_agent_output_message) showing what tool was attempted and the error. Previously, synthetic error results were only stored in history (for Bedrock message ordering) but never rendered.

Loop Prevention Guardrail (app/src/ai/blocklist/controller.rs): Detects when the agent gets stuck in a recursive failure loop (same tool + same input failing repeatedly) and injects a corrective system instruction to break the cycle. Key details:

• Tracks last 10 failed action results per conversation via LoopDetectionState
• Uses tool discriminant + Display hash to identify repeated patterns
• Threshold: 3 identical failures triggers intervention
• Intervention: injects a [SYSTEM] Loop detected user message instructing the model to take a different approach
• Clears on any successful action result (progress = not looping)
• Resets when user sends a new query

Key Architectural Patterns

1. Entity-Handle System: Views reference other views via handles, not direct ownership
2. Modular Structure: Workspace contains multiple workspace configurations, each with terminals, notebooks, etc.
3. Cross-Platform: Native implementations for macOS, Windows, Linux, plus WASM target
4. AI Integration: Built-in AI assistant with context awareness and codebase indexing
5. Cloud Sync: Objects can be synchronized across devices via Galaxy Drive

Development Guidelines

Workspace Structure:

• This is a Cargo workspace with 56 member crates
• Main binary is in app/, UI framework in crates/galaxyui*/
• Platform-specific code is conditionally compiled
• Integration tests are in crates/integration/

Coding Style Preferences:

• Avoid unnecessary type annotations, especially in closure params.
• Avoid using too many Rust path qualifiers and use imports for concision. Place import statements at the top of the file as per convention. An exception to this is inside cfg-guarded code branches. In those cases, you can either embed the import into the relevant scope or just use an absolute path for one-offs.
• If a function takes a context parameter (AppContext, ViewContext, or ModelContext), it should be named ctx and go last. The one exception is for functions that take a closure parameter, in which case the closure should be last.
• Always remove unused parameters completely rather than prefixing them with _. Update the function signature and all call sites accordingly.
• Prefer inline format arguments in macros like println!, eprintln!, and format! (for example, eprintln!("{message}") instead of eprintln!("{}", message)) to satisfy Clippy's uninlined_format_args lint.
• Do not remove existing comments when making unrelated changes. Only remove or modify a comment if the logic it describes has changed.

Terminal Model Locking:

• Be extremely careful when calling model.lock() on the terminal model (TerminalModel). Acquiring multiple locks on the same model from different call sites can cause a deadlock, resulting in a UI freeze (beach ball on macOS).
• Before adding a new model.lock() call, verify that no caller in the current call stack already holds the lock.
• Prefer passing already-locked model references down the call stack rather than acquiring new locks.
• If you must lock the model, keep the lock scope as short as possible and avoid calling other functions that might also attempt to lock.

Testing:

• Use cargo nextest for parallel test execution
• Integration tests use custom framework in crates/integration/
• Tests should be run via presubmit script before submitting
• Unit tests should be placed in separate files using the naming convention ${filename}_tests.rs or mod_test.rs
• Test files should be included at the end of their corresponding module with:

  #[cfg(test)]
  #[path = "filename_tests.rs"]  // or "mod_test.rs"
  mod tests;
  

Pull Request Workflow:

• ALWAYS run cargo fmt and cargo clippy (the versions specified in ./script/presubmit) before opening a PR or pushing updates to an existing PR branch
• Those commands must pass completely before creating or updating a pull request
• If they fail, fix all issues before proceeding with the PR
• When opening PRs, use the PR template at .github/pull_request_template.md

Database:

• Uses Diesel ORM with SQLite
• Migrations in migrations/ directory
• Schema defined in app/src/persistence/schema.rs

Feature Flags

Galaxy uses compile-time feature flags with a small runtime plumbing layer.

How to add a feature flag:

• Add a new variant to galaxy_features/src/lib.rs in the FeatureFlag enum
• (Optional) Enable it by default for dogfood builds by listing it in DOGFOOD_FLAGS
• Gate code paths with FeatureFlag::YourFlag.is_enabled()
• For preview or release rollout, add to PREVIEW_FLAGS or RELEASE_FLAGS respectively

Best practices:

• Prefer runtime checks over cfg directives: Prefer FeatureFlag::YourFlag.is_enabled() over #[cfg(...)] compile-time directives so flags can be toggled without recompilation and are easier to clean up later. Use #[cfg(...)] only when the code cannot compile without them.
• Keep flags high-level and product-focused rather than per-call-site
• Remove the flag and dead branches after launch has stabilized
• For UI sections that expose a new feature, hide the UI behind the same flag

Exhaustive Matching

When adding/editing match statements, avoid using the wildcard _ when at all possible. Exhaustive matching is helpful for ensuring that all variants are handled, especially when adding new variants to enums in the future.

Appearance Settings Notes

• Samsung-inspired built-in themes are available as SamsungDark and SamsungLight.
• UI font selection is persisted in appearance.text.ui_font_name and uses an empty string as the system-default sentinel.
• The one-click Samsung brand preset is implemented in app/src/settings_view/appearance_page.rs and applies:
  • Samsung dark/light theme mapping
  • terminal + AI font defaults
  • a best-available Samsung-style UI font fallback

Configuration

• User config directory: ~/.galaxy-ai/ (channel-suffixed for non-stable: -dev, -oss, etc.)
• Global AI rules: ~/.galaxy-ai/rules/*.md
• Skills: ~/.galaxy-ai/skills/
• MCP config: ~/.galaxy-ai/.mcp.json
• Environment variables use GALAXY_ prefix (e.g., GALAXY_API_KEY, GALAXY_INTEGRATION)

Skills

pull_warp_feature (.warp/skills/pull_warp_feature/SKILL.md): Ports features from upstream Warp into Galaxy. Clones Warp source into .galaxy/warp-upstream/ (gitignored), analyzes the feature for Warp-specific dependencies (AI → Bedrock, cloud → local storage, telemetry → removed), presents a compatibility plan, and implements the port after approval. All AI must go through BedrockClient; all cloud storage must be local.

Code Signing & Distribution

Galaxy uses Samsung's Developer ID Application certificate for macOS code signing and Apple notarization.

Signing identity: Developer ID Application: SAMSUNG ELECTRONICS AMERICA, INC. (3JU72Z7Y3J)

Entitlements (BuildSupport/Galaxy.entitlements):

• com.apple.security.network.client — AWS Bedrock API calls
• com.apple.security.automation.apple-events — osascript for CLI install
• com.apple.security.cs.allow-unsigned-executable-memory — Metal shader compilation

Build & distribute pipeline:

# Debug (unoptimized, ~149MB)
./build-debug.sh

# Release (optimized, smaller)
./build-release.sh

# Or step by step:
cargo bundle [--release] --bin galaxy-oss --package galaxy
./sign.sh [--release]
./notarize.sh [--release]
./package.sh [--release]

# Copy DMGs to ~/Downloads with date suffix
./copy-dmgs.sh

Output: target/{debug|release}/bundle/osx/Galaxy.dmg — signed, notarized, stapled. Users can download, open, drag to Applications, launch without Gatekeeper warnings.

Install from source (end users):

./script/install-galaxy.sh

Bedrock Diagnostics

When GALAXY_BEDROCK_DIAGNOSTICS=1 is set, the diagnostic logger writes to bedrock-diagnostics.log in the log directory. On API errors, a comprehensive JSON snapshot (Error_YYYYMMDD_HHMMSS_mmm.txt) is written to the repo root (or cwd/tmp) containing the full request context, captured log lines, and log tails.

Future Work

IDE-Level LSP Integration

Add Zed-quality IDE capabilities on top of Galaxy's existing LSP client (crates/lsp/) and editor (crates/editor/). Current state is bare-bones terminal-input-scoped; goal is full project-level editing with:

• Completion popover (hook LSP textDocument/completion, render dropdown)
• Inline diagnostics (subscribe textDocument/publishDiagnostics, render underlines/squiggles)
• Hover/signature help (tooltip overlay)
• Multi-file editing with go-to-definition, project-wide buffers, file tabs
• Reference: Zed — Rust-native, GPU-rendered, tree-sitter syntax, tower-lsp protocol. Architecturally compatible with Galaxy's primitives.