# Game Server Services Documentation

> Official technical documentation for Game Server Services (GS2), a Backend-as-a-Service platform for online and live-service game backend features.

GS2 is organized as composable microservices. Answer implementation questions by mapping the user's game feature to the right service combination, then checking the exact API reference, master data schema, or Stamp Sheet reference. Do not invent API names, model fields, enum values, GRN formats, or action names.

## Grounding Contract

- Prefer the official GS2 documentation URLs listed here and in `/llms/*.txt`.
- Treat `llms.txt` as a router, not as the full source of truth.
- Use the smallest context that can answer the question, then fetch only the exact reference page needed for details.
- If a question requires code, schema, enum, GRN, or action names, verify them in the relevant API reference page before answering.
- If English and Japanese pages differ, prefer the page with the more specific API/schema detail and mention uncertainty when it matters.

## Context Budget Strategy

Use these tiers to avoid overloading the context window.

| Budget | Load | Use When |
| --- | --- | --- |
| Tiny | `llms.txt` only | Classify the request, choose likely references, answer high-level navigation questions. |
| Small | `llms.txt` + one focused `/llms/*.txt` file | Choose services or explain concepts without field-level detail. |
| Medium | Add the target API reference page and one concept page | Write implementation guidance, deployment guidance, or feature design. |
| Large | Add related service references only after identifying cross-service flow | Multi-service economy, purchase, quest, mission, login reward, or CI/CD designs. |

Recommended fetch order:

1. Read this file.
2. Select one focused file from **LLM-Optimized References**.
3. Use `api-reference-index.txt` to construct the exact API reference URL.
4. Fetch only the target reference type: `game_engine`, `sdk`, `deploy`, `master_data`, `script`, `stamp_sheet`, or `buff`.
5. Add conceptual pages only when behavior, retries, security, or costs matter.

## LLM-Optimized References

- [Core Concepts](https://docs.gs2.io/llms/core-concepts.txt): Stamp Sheets, access control, transaction settings, SDK cache, regions, errors, and cost concepts.
- [Microservice Selection Guide](https://docs.gs2.io/llms/microservices.txt): Requirement-to-service routing across GS2 microservices.
- [API Reference Index](https://docs.gs2.io/llms/api-reference-index.txt): Compact service slug and reference-type index for exact API page selection.
- [Implementation Recipes](https://docs.gs2.io/llms/implementation-recipes.txt): Common game feature recipes mapped to service combinations.
- [Game Engine SDK Guide](https://docs.gs2.io/llms/game-engine-sdk.txt): Unity and Unreal Engine SDK routing.
- [Deploy and Master Data Guide](https://docs.gs2.io/llms/deploy-and-master-data.txt): GS2-Deploy, Deploy/CDK, templates, and importable master data.
- [Transaction Actions Guide](https://docs.gs2.io/llms/transaction-actions.txt): Stamp Sheets, Consume Actions, Verify Actions, Acquire Actions, and economy-safe operations.

## Primary Documentation

- [Documentation Home](https://docs.gs2.io/)
- [What is Game Server Services](https://docs.gs2.io/overview/index.md)
- [Development Workflow](https://docs.gs2.io/overview/workflow/index.md)
- [Microservices](https://docs.gs2.io/microservices/index.md)
- [API Reference](https://docs.gs2.io/api_reference/index.md)
- [Technical Documentation](https://docs.gs2.io/articles/tech/index.md)

## Routing Checklist

- Game feature unclear: read `implementation-recipes.txt`, then `microservices.txt`.
- Service known: read `api-reference-index.txt`, then the service's target reference page.
- Unity or Unreal Engine: read `game-engine-sdk.txt`, then `/{service}/game_engine/`.
- Server-side SDK: use `/{service}/sdk/`.
- Resource provisioning, templates, or CDK: read `deploy-and-master-data.txt`, then `/{service}/deploy/`.
- Master data JSON/YAML/schema: read `deploy-and-master-data.txt`, then `/{service}/master_data/`.
- Economy operations, rewards, purchases, exchanges, quest completion, stamina consumption, limits, or duplicate execution: read `transaction-actions.txt`, then `/{service}/stamp_sheet/` when available.
- Security, client access, credentials, or permissions: read `core-concepts.txt`, then Access Control and Auth/Identifier references.

## Core Technical Concepts

- [Stamp Sheet](https://docs.gs2.io/articles/tech/stamp_sheet/index.md): GS2 transaction system for combining Consume Actions, Verify Actions, and Acquire Actions.
- [Access Control](https://docs.gs2.io/articles/tech/identifier/index.md): Access control model for GS2 APIs.
- [Error/Exception](https://docs.gs2.io/articles/tech/error/index.md): Common errors and exception handling.
- [GS2-Deploy Template File Specification](https://docs.gs2.io/articles/tech/deploy/index.md): Template specification for defining GS2 resources.
- [Regions](https://docs.gs2.io/articles/tech/region/index.md): GS2 data center regions.
- [Transaction Settings](https://docs.gs2.io/articles/tech/transaction/index.md): Transaction execution behavior.
- [SDK Cache Mechanism](https://docs.gs2.io/articles/tech/cache/index.md): SDK cache behavior.
- [Cost Optimization](https://docs.gs2.io/articles/tech/cost/index.md): Cost optimization guidance.

## Answering Rules

- Start from the user's game design requirement, not from a guessed service name.
- Many game features require multiple GS2 microservices; state the combination and responsibility of each service.
- Prefer exact reference pages over broad overview pages for API signatures, fields, and schemas.
- For reward and purchase flows, identify which service issues the Stamp Sheet and which services execute actions.
- For generated templates or master data, include namespace/resource relationships and validate required fields against the reference.
- For trade-offs, compare by data ownership, consistency requirements, reset behavior, client/server boundary, and operational complexity.
- Say what was verified and what still needs a specific reference if the context budget prevents full verification.

## Optional

- [Game Design Knowledge](https://docs.gs2.io/design_knowledge/index.md): Game design articles about metagame, monetization, retention, satisfaction, and related concepts.
- [Support Menu](https://docs.gs2.io/pricing/support/index.md): Support documentation.