MythxEngine
NPM · @MYTHXENGINE/MCP-SERVER · 2 COMPONENTS · SCANNED SEP 21
Tabletop RPG engine over MCP: dice, combat, stress, clocks, world generation, four bundled worlds
Available components
How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. How we score → Why this is hard to score →
Supply Chain Security98
- No malware found by supply-chain analysis.Pass
- No known CVEs affecting this package version or its production dependencies.Pass
- No install/post-install scripts declared.Pass
- 31 of 97 dependencies flagged as unhealthy. View diagnostics → Partial
Provenance & Transparency97
- Source repository is publicly reachable at the declared URL. View diagnostics → Pass
- Cryptographically verified build provenance (signed, bound to protoLabsAI/mythx-mcp). View diagnostics → Pass
- Clear OSI-approved license (MIT).Pass
- Actively maintained (last published 31 days ago).Pass
- Disclosure check failed: no security disclosure policy was found in the source repository. See how to fix → Fail
Schema Quality & AI Usability47
- 0% of prompts and resources have a non-trivial description (not blank, and not just the item's name).Fail
- AI-judged instruction clarity (good).Pass
- Tool/resource definitions use about 12305 tokens (~75/item across 164 items; 158 tools + 6 resources), lean.Pass
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management97
- Stability observed for 29 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 99% of tool parameters carry a description.Partial
Tool Safety75
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- 0 of 10 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation; "remove_condition" implies "remove" and declares no destructiveHint at all, which the MCP spec reads as destructive by default. See how to fix → Fail
- An AI judge read all 159 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
How do I install the MythxEngine MCP server?
MythxEngine runs locally as an npm package, launched with npx -y @mythxengine/mcp-server. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
npm · @mythxengine/mcp-server
claude mcp add protolabsai-mythxengine -- npx -y @mythxengine/mcp-server
{
"mcpServers": {
"protolabsai-mythxengine": {
"command": "npx",
"args": [
"-y",
"@mythxengine/mcp-server"
]
}
}
} {
"servers": {
"protolabsai-mythxengine": {
"command": "npx",
"args": [
"-y",
"@mythxengine/mcp-server"
]
}
}
} codex mcp add protolabsai-mythxengine -- npx -y @mythxengine/mcp-server
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"protolabsai-mythxengine": {
"type": "local",
"command": [
"npx",
"-y",
"@mythxengine/mcp-server"
],
"enabled": true
}
}
} openclaw mcp add protolabsai-mythxengine --command npx --arg -y --arg @mythxengine/mcp-server
mcp_servers:
protolabsai-mythxengine:
command: "npx"
args: ["-y", "@mythxengine/mcp-server"] {
"McpServers": {
"protolabsai-mythxengine": {
"Transport": "stdio",
"Command": "npx",
"Arguments": [
"-y",
"@mythxengine/mcp-server"
]
}
}
} assistant mcp add protolabsai-mythxengine -t stdio -c npx -a -y @mythxengine/mcp-server
{
"mcpServers": {
"protolabsai-mythxengine": {
"command": "npx",
"args": [
"-y",
"@mythxengine/mcp-server"
]
}
}
} Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 19 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 90 to 93. That category is still filling its 30-day observation window: 27 days of observed history at the previous scan, 28 at this one. The score rises as the window fills, whether or not the server changes.
- 17 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 83 to 87. That category is still filling its 30-day observation window: 25 days of observed history at the previous scan, 26 at this one. The score rises as the window fills, whether or not the server changes.
- 16 Sept 26 −3
- Stability: pass → 0.83 functional
- 15 Sept 26 +1
- Stability: 0.97 → pass security
- 13 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 90 to 93. That category is still filling its 30-day observation window: 27 days of observed history at the previous scan, 28 at this one. The score rises as the window fills, whether or not the server changes.
- 11 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 83 to 87. That category is still filling its 30-day observation window: 25 days of observed history at the previous scan, 26 at this one. The score rises as the window fills, whether or not the server changes.
- 9 Sept 26 −3
- Stability: pass → 0.80 functional
- 8 Sept 26 +1
- Stability: 0.97 → pass security
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 20 Sept 2026 · Analysed npm/@mythxengine/mcp-server@0.3.0
Provenance Verified
A signed build attestation was found and verified, binding this exact artifact to the source repository it claims to come from.
| Result | Verified |
|---|---|
| Ecosystem | npm |
| Reason | Verified |
| Discovered via | Registry attestation endpoint |
| Source repo | protoLabsAI/mythx-mcp |
| Certificate issuer | https://token.actions.githubusercontent.com |
| Certificate SAN | https://github.com/protoLabsAI/mythx-mcp/.github/workflows/release.yml@refs/tags/v0.3.0 |
| Rekor log index | 2148358974 |
| Predicate type | https://slsa.dev/provenance/v1 |
| Subject digest | sha512:76d0217672d7803fdb6639fbbe58ea06794d12571f3cbf4ca78491690cbd6d7554fcae41ea3eb7cd6e8873ffa915ff4bd9d457a393bd78aa1cfb9c608 |
Background: How many MCP packages publish verified provenance →
Dependencies 97 packages
| Packages resolved | 97 |
|---|---|
| Stale | 31 |
| Tree resolution | Complete |
Background: SBOMs and build attestations, explained →
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
update_companion_state ~243
Update an AI companion's internal state (loyalty, mood, grievances, memories). Call after events that would plausibly affect the companion's attitude toward the party.
| Name | Type | Req | Description |
|---|---|---|---|
| characterId | string | yes | The AI companion's character ID |
| fireTrigger | string | – | ID of a loyalty trigger that was fired — marks it as fired and applies its effect |
| hiddenAgenda | string|null | – | Set or clear the companion's hidden agenda |
| loyaltyDelta | number | – | Change to party loyalty (negative = losing trust, positive = gaining trust) |
| moodShift | string | – | New mood descriptor for the companion |
| newAdmiration | string | – | Something the companion now admires |
| newDisagreement | string | – | A new active disagreement |
| newGrievance | string | – | A new grievance the companion is holding |
| newMemory | object | – | A new memory to record (always marked unresolved) |
| playerLoyaltyDelta | object | – | Per-player trust changes keyed by player ID |
| reason | string | – | Why the loyalty changed — used in narrative context |
| sessionId | string | yes | Session ID |
No output schema declared.
No examples provided.
update_investigation_status ~51
Mark an investigation as solved, cold, or abandoned.
| Name | Type | Req | Description |
|---|---|---|---|
| investigationId | string | yes | Investigation ID |
| sessionId | string | yes | Session ID |
| status | string | yes | New status |
No output schema declared.
No examples provided.
update_pacing_state ~119
Update narrative pacing state after each beat. Track tension level, phase transitions, and spotlight rotation to maintain balanced storytelling.
| Name | Type | Req | Description |
|---|---|---|---|
| incrementBeat | boolean | – | Increment the scene beat count (call after each narrative beat) |
| phase | string | – | Shift the narrative phase (omit to keep current phase) |
| sessionId | string | yes | Session ID |
| spotlightPlayerId | string | – | Record that this player received spotlight this beat |
| tensionDelta | number | – | Adjust tension level by this amount (positive = more tension, negative = less) |
No output schema declared.
No examples provided.
update_player ~107
Update a player's status, name, controlType, or AI persona
| Name | Type | Req | Description |
|---|---|---|---|
| aiPersona | object | – | Update AI persona (for AI players) |
| characterId | string|null | – | New character ID (or null to unlink) |
| controlType | string | – | Switch between human and AI control |
| name | string | – | New display name |
| playerId | string | yes | Player ID |
| sessionId | string | yes | Session ID |
| status | string | – | New status |
No output schema declared.
No examples provided.
update_relationship ~196
Record an interaction and update NPC relationship. Automatically adjusts attitude based on impact.
| Name | Type | Req | Description |
|---|---|---|---|
| actingCharacterId | string | – | Character ID of the PC who caused this interaction (tracks per-PC attitudes) |
| addFears | array | – | Add fears |
| addKnows | array | – | Add to what NPC knows |
| addOwes | array | – | Add debts/favors |
| addWants | array | – | Add wants |
| attitudeChange | string | – | Explicit attitude override (optional) |
| impact | string | yes | How this affected the relationship |
| interaction | string | yes | Description of what happened |
| npcId | string | yes | NPC ID |
| removeFears | array | – | Remove fears |
| removeKnows | array | – | Remove from knows |
| removeOwes | array | – | Remove debts |
| removeWants | array | – | Remove wants |
| sessionId | string | yes | Session ID |
No output schema declared.
No examples provided.
upgrade_inventory ~112
Convert a character from narrative to itemized inventory mode. Enables full item tracking with stats, equipment slots, gold, and weight/encumbrance.
| Name | Type | Req | Description |
|---|---|---|---|
| characterId | string | yes | Character ID to upgrade |
| maxSlots | integer | – | Maximum inventory slots |
| maxWeight | number | – | Maximum carry weight |
| preserveNarrative | boolean | – | Keep narrative equipment as reference (stored in narrative field) |
| sessionId | string | yes | Session ID |
| startingGold | integer | – | Starting gold amount |
No output schema declared.
No examples provided.
use_item ~87
Use a consumable item. Applies healing or effects, decrements uses, and removes item when depleted.
| Name | Type | Req | Description |
|---|---|---|---|
| characterId | string | yes | Character ID using the item |
| itemId | string | yes | Item instance ID to use |
| sessionId | string | yes | Session ID |
| targetCharacterId | string | – | Target character ID (for items that affect others). Defaults to self. |
No output schema declared.
No examples provided.
validate_world_pack ~52
Check a world pack for completeness, consistency, and broken references.
| Name | Type | Req | Description |
|---|---|---|---|
| packId | string | – | Pack ID (if validating saved pack) |
| sessionId | string | – | Session ID (if validating from session) |
No output schema declared.
No examples provided.
What is the MythxEngine MCP server?
MythxEngine is an MCP server listed in the public MCP registry as io.github.protoLabsAI/mythxengine. Tabletop RPG engine over MCP: dice, combat, stress, clocks, world generation, four bundled worlds. This page covers its npm package (@mythxengine/mcp-server).
Is the MythxEngine MCP server safe to use?
MythxEngine scores 87 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 20 September 2026. It declares no install or post-install scripts. Its build provenance is signed and verified. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the MythxEngine MCP server expose?
MythxEngine exposes 158 tools: roll_dice, roll_test, roll_custom_test, get_character, create_character, and 153 more. Their descriptions and schemas cost roughly 12,266 tokens of context every time the server is loaded.
Is the MythxEngine MCP server still maintained?
MythxEngine is still listed as active in the MCP registry. We last reached this channel on 20 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.
What licence is the MythxEngine MCP server under?
MythxEngine declares the MIT licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.