What is change-map-size?

A guide for changing the dimensions of a game world. It lists the server and client settings that must match and the edge settings that control deep-sea areas, ambient behavior, procedural rendering, and the minimap.

Use it when changing the world from one tile size to another, checking deep-sea borders, or reviewing edge-related rendering and sound behavior.

Changing the map size in only one place can make world edges, ocean areas, sounds, or the minimap behave incorrectly. This guide helps keep related size and edge settings aligned.

change-map-size — Cursor rule for Cursor by SeloSlav

Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo

git clone --depth 1 https://github.com/SeloSlav/2d-multiplayer-survival-mmorpg

agentmods

npx agentmods add rules/seloslav/2d-multiplayer-survival-mmorpg/change-map-size

Made for: Cursor.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/rules/seloslav/2d-multiplayer-survival-mmorpg/change-map-size/github.svg)](https://agentmods.dev/rules/seloslav/2d-multiplayer-survival-mmorpg/change-map-size)

Your own site

<a href="https://agentmods.dev/rules/seloslav/2d-multiplayer-survival-mmorpg/change-map-size"><img src="https://agentmods.dev/badge/rules/seloslav/2d-multiplayer-survival-mmorpg/change-map-size/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/rules/seloslav/2d-multiplayer-survival-mmorpg/change-map-size"><img src="https://agentmods.dev/badge/rules/seloslav/2d-multiplayer-survival-mmorpg/change-map-size.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 15 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 520 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00015	$0.00520
Opus 5	$0.00008	$0.00260
Sonnet 5	$0.00003	$0.00104
Haiku 4.5	$0.00002	$0.00052

Measured 9d ago against content hash 020ffd4367c6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

change-map-size 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 9d 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.

.cursor/rules/change-map-size.mdc · 68 lines

How it starts

The opening of the file, as written. The whole thing — 68 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Map Size Change Guide

Use this when changing world dimensions (for example 800x800 to 1000x1000).

Core Files to Update

server/src/lib.rs

pub const WORLD_WIDTH_TILES: u32 = NEW_SIZE;
pub const WORLD_HEIGHT_TILES: u32 = NEW_SIZE;

client/src/config/gameConfig.ts

const SERVER_WORLD_WIDTH_TILES = NEW_SIZE;
const SERVER_WORLD_HEIGHT_TILES = NEW_SIZE;

Deep Sea / Edge-Zone Sync (Important)

Map-size changes affect edge behavior and ocean presentation. Verify these values remain intentional:

Server deep-sea perimeter width:

server/src/environment.rs
DEEP_SEA_OUTER_RING_TILES

Client fallback deep-sea edge width:

client/src/config/gameConfig.ts
DEEP_SEA_EDGE_TILES

These two should stay aligned unless you intentionally want different behavior.

Why Deep Sea Matters

World-edge ambient logic in client/src/components/GameCanvas.tsx uses gameConfig.worldWidthPx and gameConfig.worldHeightPx.
Ambient selection in client/src/hooks/useAmbientSounds.ts uses distanceToMapEdge thresholds.
Procedural fallback rendering and minimap deep-sea coloring can look wrong if edge constants are out of sync.

Build / Republish Sequence

From project root:

spacetime build -p ./server
spacetime publish -c -p ./server broth-bullets-local
spacetime generate --lang typescript --out-dir ./client/src/generated -p ./server

Restart client after generation (npm run dev if needed).

Validation Checklist

Server and client world tile sizes match.
Server DEEP_SEA_OUTER_RING_TILES and client DEEP_SEA_EDGE_TILES intentionally match.
Player edge proximity sounds still feel correct (shore vs deep ocean near map edge).
Minimap deep-sea ring looks expected.
Ocean/deep-sea spawn behavior near perimeter still matches design intent.

Common Pitfalls

Updating only server or only client dimensions.
Forgetting to regenerate bindings after server-side changes.
Assuming deep-sea ring should stay fixed for every map size without re-evaluation.

Read the full file on GitHub · 68 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.

9d ago First seen · 68 lines · 15 tokens per session scan A 020ffd4367c6

Subscribe to this mod's changes

change-map-size is a cursor rule published in the GitHub repository SeloSlav/2d-multiplayer-survival-mmorpg (178 stars, last pushed 20d ago), licensed Apache-2.0. It adds 15 tokens to every session and 520 once invoked, about $0.0001 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 2026-08-30.

Game development

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change-map-size