Modify secret visibility. Reveal to specific characters and/or make public in a single call. Call this immediately when a character learns something - through dialogue, investigation, or discovery. Track what each character knows.
AI agents use modify_secret_visibility to create or update resources in DMCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your DMCP environment.
The tool modifies game metadata (secret visibility and character knowledge) rather than executing arbitrary code or destructively removing data. It is a reversible write operation that updates the game state. While it affects game progression, the modification can be undone by calling the tool again with different parameters.
From the tool's definition Tool description states 'Modify secret visibility. Reveal to specific characters and/or make public' - this modifies game state by changing visibility/knowledge tracking for secrets, which is a reversible state change operation.
Documented attack patterns abuse exactly the kind of access modify_secret_visibility gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and DMCP, and nothing reaches the server without passing your rules. This is the rule we recommend for modify_secret_visibility:
{
"version": "1",
"default": "deny",
"tools": {
"modify_secret_visibility": {
"limits": [
{
"counter": "modify_secret_visibility_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}modify_secret_visibility stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Modify secret visibility. Reveal to specific characters and/or make public in a single call. Call this immediately when a character learns something - through dialogue, investigation, or discovery. Track what each character knows. It is categorised as a Write tool in the DMCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the D MCP server in PolicyLayer and add a rule for modify_secret_visibility: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches DMCP. Nothing to install.
modify_secret_visibility is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the modify_secret_visibility rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for modify_secret_visibility. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
modify_secret_visibility is provided by the D MCP server (shawnrushefsky/dmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from DMCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
204 DMCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.