Fvtt Chat Messages

Foundry VTT Chat Messages

Domain: Foundry VTT Module/System Development Status: Production-Ready Last Updated: 2026-01-05

Overview

ChatMessage documents display in the chat log and handle rolls, whispers, and player communication. Understanding message creation and hooks is essential for game system features.

When to Use This Skill

• Creating chat messages programmatically
• Sending dice roll results to chat
• Configuring message speakers
• Implementing whispers and roll modes
• Adding custom rendering to messages

ChatMessage Structure

Core Fields

{
  _id: "documentId",
  author: "userId",           // Who created the message
  content: "<p>HTML</p>",     // Message content
  flavor: "Roll description", // Flavor text for rolls
  speaker: {                  // Who is "speaking"
    scene: "sceneId",
    actor: "actorId",
    token: "tokenId",
    alias: "Display Name"
  },
  whisper: ["userId"],        // Private recipients
  blind: false,               // GM-only visibility
  rolls: [],                  // Dice roll data
  sound: "audio/path.ogg",    // Sound to play
  flags: {}                   // Custom data
}

Creating Messages

Simple Text Message

await ChatMessage.create({
  content: "Hello, world!"
});

Message with Speaker

await ChatMessage.create({
  content: "I attack the dragon!",
  speaker: ChatMessage.getSpeaker({ actor: myActor })
});

HTML Content

await ChatMessage.create({
  content: `
    <h2>Critical Hit!</h2>
    <p>You deal <strong>24</strong> damage.</p>
  `,
  speaker: ChatMessage.getSpeaker({ token: myToken })
});

With Custom Flags

await ChatMessage.create({
  content: "Attack roll",
  flags: {
    "my-module": {
      rollType: "attack",
      targetId: target.id
    }
  }
});

Roll Messages

Using Roll.toMessage() (Recommended)

const roll = new Roll("1d20 + @mod", { mod: 5 });
await roll.evaluate();

await roll.toMessage({
  speaker: ChatMessage.getSpeaker({ actor }),
  flavor: "Attack Roll"
});

With Roll Mode

await roll.toMessage({
  speaker: ChatMessage.getSpeaker({ actor }),
  flavor: "Stealth Check"
}, {
  rollMode: game.settings.get("core", "rollMode")
});

Multiple Rolls

const attackRoll = new Roll("1d20 + 5");
const damageRoll = new Roll("2d6 + 3");

await attackRoll.evaluate();
await damageRoll.evaluate();

await ChatMessage.create({
  speaker: ChatMessage.getSpeaker({ actor }),
  flavor: "Attack and Damage",
  rolls: [attackRoll, damageRoll]
});

Speaker Configuration

getSpeaker()

// From controlled token (default)
const speaker = ChatMessage.getSpeaker();

// From specific actor
const speaker = ChatMessage.getSpeaker({ actor: myActor });

// From specific token
const speaker = ChatMessage.getSpeaker({ token: myToken });

// Custom alias
const speaker = ChatMessage.getSpeaker({ alias: "The Narrator" });

Speaker Structure

{
  scene: "sceneId",      // Scene where speaker is
  actor: "actorId",      // Actor document ID
  token: "tokenId",      // Token document ID
  alias: "Display Name"  // Fallback name
}

Get Speaker's Actor

const actor = ChatMessage.getSpeakerActor(message.speaker);

Whispers and Roll Modes

Roll Modes

Apply Roll Mode

// Get current setting
const rollMode = game.settings.get("core", "rollMode");

// Apply to roll
await roll.toMessage({
  speaker: ChatMessage.getSpeaker({ actor })
}, {
  rollMode: rollMode
});

Whisper to Specific Users

// Single user
await ChatMessage.create({
  content: "Secret message",
  whisper: [targetUserId]
});

// Multiple users
await ChatMessage.create({
  content: "Group secret",
  whisper: [user1Id, user2Id]
});

// All GMs
await ChatMessage.create({
  content: "GM only",
  whisper: game.users.filter(u => u.isGM).map(u => u.id)
});

Blind Messages

// GM sees content, others see "???"
await ChatMessage.create({
  content: "Secret roll result: 15",
  blind: true,
  whisper: game.users.filter(u => u.isGM).map(u => u.id)
});

Chat Hooks

renderChatMessageHTML (V13+)

Hooks.on("renderChatMessageHTML", (message, html, context) => {
  // message: ChatMessage document
  // html: HTMLElement
  // context: Rendering context

  // Add custom styling
  if (message.flags["my-module"]?.critical) {
    html.classList.add("critical-hit");
  }

  // Add buttons
  const button = document.createElement("button");
  button.textContent = "Apply Damage";
  button.addEventListener("click", () => applyDamage(message));
  html.querySelector(".message-content").append(button);
});

preCreateChatMessage

Hooks.on("preCreateChatMessage", (message, data, options, userId) => {
  // Modify before creation
  message.updateSource({
    content: data.content + " (modified)"
  });

  // Return false to cancel
  return true;
});

createChatMessage

Hooks.on("createChatMessage", (message, options, userId) => {
  // After creation, for all clients
  console.log("New message:", message.content);
});

chatMessage

Hooks.on("chatMessage", (chatLog, messageText, chatData) => {
  // When user sends message via input
  // Return false to prevent default handling

  if (messageText.startsWith("/custom")) {
    handleCustomCommand(messageText);
    return false;
  }
});

Common Patterns

Roll with Button

async function attackRoll(actor, target) {
  const roll = new Roll("1d20 + @mod", actor.getRollData());
  await roll.evaluate();

  await roll.toMessage({
    speaker: ChatMessage.getSpeaker({ actor }),
    flavor: `Attack vs ${target.name}`,
    flags: {
      "my-system": {
        type: "attack",
        targetId: target.id,
        total: roll.total
      }
    }
  });
}

// Handle button clicks
Hooks.on("renderChatMessageHTML", (message, html) => {
  const flags = message.flags["my-system"];
  if (flags?.type !== "attack") return;

  html.querySelector(".apply-damage")?.addEventListener("click", () => {
    const target = game.actors.get(flags.targetId);
    // Apply damage logic
  });
});

Collapsible Details

await ChatMessage.create({
  content: `
    <div class="roll-result">
      <h3>Attack Roll: 18</h3>
      <details>
        <summary>Details</summary>
        <p>Base: 1d20 = 13</p>
        <p>Modifier: +5</p>
      </details>
    </div>
  `
});

Sound with Message

await ChatMessage.create({
  content: "The bell tolls...",
  sound: "sounds/bell.ogg"
});

Common Pitfalls

1. Forgetting Roll Evaluation

// WRONG - total is undefined
const roll = new Roll("1d20");
await roll.toMessage();  // roll.total undefined!

// CORRECT
const roll = new Roll("1d20");
await roll.evaluate();
await roll.toMessage();

2. Wrong Speaker Token

// WRONG - uses first controlled token
ChatMessage.getSpeaker();

// CORRECT - specify the token
ChatMessage.getSpeaker({ token: specificToken });

3. Whisper vs Roll Mode Conflict

// Roll messages override whisper with rollMode
// Use rollMode for roll messages:
await roll.toMessage({}, {
  rollMode: "gmroll"  // Not whisper: [...]
});

4. Ignoring Roll Mode Setting

// WRONG - always public
await roll.toMessage();

// CORRECT - respect user setting
await roll.toMessage({}, {
  rollMode: game.settings.get("core", "rollMode")
});

5. Message Update Timing

// Updating too fast causes UI issues
// Wait for notification to fade (~3 seconds)
const msg = await ChatMessage.create({ content: "Loading..." });
setTimeout(() => {
  msg.update({ content: "Done!" });
}, 3500);

6. Not Checking Visibility

// Check if message is visible to current user
if (!message.visible) return;

// Check if content is visible (not just presence)
if (message.isContentVisible) {
  // Safe to read content
}

Implementation Checklist

• Use ChatMessage.getSpeaker() for proper speaker
• Always await roll.evaluate() before toMessage
• Respect game.settings.get("core", "rollMode")
• Use renderChatMessageHTML hook for customization
• Store custom data in flags, not content
• Handle whisper recipients appropriately
• Test all roll modes (public, GM, blind, self)
• Add sound effects where appropriate

References

• ChatMessage API
• Chat Messages Article
• Roll API
• renderChatMessageHTML Hook

Last Updated: 2026-01-05 Status: Production-Ready Maintainer: ImproperSubset