Change the tempo of the selected audio without changing pitch.
AI agents use effect_change_tempo to create or update resources in AudacityMCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your AudacityMCP environment.
This tool modifies audio data (Write category) rather than merely reading it or destructively deleting it. The change is reversible via undo functionality typical in audio editors like Audacity. The severity is medium because misuse could alter user audio projects, but the effects are undoable and non-destructive. Confidence is high based on clear naming and description indicating a modification operation.
From the tool's definition Tool is named 'effect_change_tempo' and described as 'Change the tempo of the selected audio without changing pitch.' This modifies audio data by adjusting playback speed while preserving pitch, which is a reversible transformation of the audio content.
Documented attack patterns abuse exactly the kind of access effect_change_tempo gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and AudacityMCP, and nothing reaches the server without passing your rules. This is the rule we recommend for effect_change_tempo:
{
"version": "1",
"default": "deny",
"tools": {
"effect_change_tempo": {
"limits": [
{
"counter": "effect_change_tempo_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}effect_change_tempo 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.
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Change the tempo of the selected audio without changing pitch. It is categorised as a Write tool in the AudacityMCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Audacity MCP server in PolicyLayer and add a rule for effect_change_tempo: 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 AudacityMCP. Nothing to install.
effect_change_tempo 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 effect_change_tempo 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 effect_change_tempo. 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.
effect_change_tempo is provided by the Audacity MCP server (xdarkzx/audacity-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 131 AudacityMCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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131 AudacityMCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.