This record as markdown: /tools/io-github-alxpark-propresenter-mcp/timers-start.md
What timers_start does on Propresenter
AI agents invoke timers_start to trigger actions in Propresenter. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
Why timers_start is rated High
The tool executes a command that initiates a timer in an external application, which is an operational side effect. It is not a simple read operation (no data retrieval), nor is it destructive or financial. It falls under Execute because it triggers an external operation whose actual impact depends on the arguments provided (which specific timer, and what that timer controls in the presentation context).
From the tool's definition Tool name 'timers_start' and description 'Start a specific timer' indicate this triggers an external operation (timer activation) on ProPresenter 7, which is an audio/visual presentation software.
Attacks that exploit this kind of access
The rule that runs timers_start safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Propresenter, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For timers_start, this is the rule to start with:
timers_start stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Propresenter, apply this rule, and every timers_start call is checked against it from then on.
Questions about timers_start
Start a specific timer. It is categorised as a Execute tool in the Propresenter MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Propresenter MCP server in PolicyLayer and add a rule for timers_start: 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 Propresenter. Nothing to install.
timers_start is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the timers_start 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 timers_start. 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.
timers_start is provided by the Propresenter MCP server (@alxpark/propresenter-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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