Report when this MCP server couldn't fully answer a question. Not a query tool — calling this writes a feedback record. Call this proactively — without being asked — whenever you hit one of: - missing_field: a field you expected on a module wasn't present (e.g. "I needed the LFO frequency range o...
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AI agents use report_gap to create or modify resources in Eurorack. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call report_gap repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Eurorack.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"report_gap": {
"limits": [
{
"counter": "report_gap_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Eurorack policy for all 17 tools.
These attack patterns abuse exactly the kind of access report_gap gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Report when this MCP server couldn't fully answer a question. Not a query tool — calling this writes a feedback record. Call this proactively — without being asked — whenever you hit one of: - missing_field: a field you expected on a module wasn't present (e.g. "I needed the LFO frequency range on Pamela's New Workout and parameter_zones didn't have it"). - missing_module: a module the user asked about isn't in the corpus yet. - tool_confusion: a tool's behavior surprised you (wrong shape, missing filter, ambiguous enum value, unclear description). - empty_result: a reasonable query came back empty and you suspect the corpus is incomplete rather than the query being wrong. - other: anything else worth flagging that doesn't fit above. - eval_finding: reserved for the eval harness at evals/mcp/. Don't use this as an agent — it's written by harvest.py --push when a rubric catches a behavior the agent didn't self-report (e.g., a model leaking prior knowledge after acknowledging a corpus gap). Be specific. Vague reports ("data could be better") are useless; actionable reports name the field, module, or tool. Reporting is encouraged — there is no rate limit and no judgment for over-reporting; a noisy log is more useful than a silent one. Args: - kind (required): one of missing_field | missing_module | tool_confusion | empty_result | other (eval_finding is reserved for the eval harness) - module_id: module this was about, if any ("<manufacturer>/<slug>"). For missing_module, use the id the user asked about even if it doesn't exist. - tool_name: tool that fell short (or that you'd want to exist). - expected (required, ≤200 chars): what you were trying to find or do. - observed (required, ≤500 chars): what actually happened. - suggestion (≤300 chars): concrete fix you'd propose ("add a release_curve field to parameters", "ingest mutable-instruments/yarns"). Returns: { acknowledged: true, id: number }. It is categorised as a Write tool in the Eurorack MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Eurorack MCP server in PolicyLayer and add a rule for report_gap: 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 Eurorack. Nothing to install.
report_gap 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 report_gap 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 report_gap. 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.
report_gap is provided by the Eurorack MCP server (https://eurorackref.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 17 Eurorack tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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