Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add rules/giantswarm/mcp-prometheus/mcp-debugginggit clone --depth 1 https://github.com/giantswarm/mcp-prometheusWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00486 | $0.00486 |
| Opus 5 | $0.00243 | $0.00243 |
| Sonnet 5 | $0.00097 | $0.00097 |
| Haiku 4.5 | $0.00049 | $0.00049 |
Grade A, and why
mcp-debugging scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 62 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Debugging mcp-prometheus via mcp-debug
mcp-debug provides core debugging tools to test and explore the functionality implemented in the aggregated MCP server. This guide focuses on mcp-debugs internal debugging capabilities.
Core Debugging Tools
mcp-debug exposes these categories of internal tools for debugging the aggregated mcp server end-to-end:
list_tools: list all the tools exposed by the aggregated mcp server describe_tool: describe a tool exposed by the aggregated mcp server call_tool: execute a tool exposed by the aggregated mcp server
Debugging Workflow
1. Verify All Services Are Running
Start by checking the overall health of the system:
mcp_mcp-debug_call_tool(name="core_service_list", arguments={})
2. Check MCP Server Registration
Verify that all expected MCP servers are properly registered with the aggregator:
mcp_mcp-debug_call_tool(name="core_mcp_server_list", arguments={})
5. Troubleshoot Connection Issues
If a service shows as unhealthy:
- Check its detailed status:
core_service_status - Try restarting it:
core_service_restart - Check if its MCP client is attached in the service list
Important Notes
- The prefix
x_is configurable viaEnvctlPrefixin the aggregator config - Tool names from individual MCP servers get prefixed to avoid conflicts
- The agent automatically handles tool name resolution and routing
- Service health is continuously monitored and reflected in the status
- Workflows provide a way to test complex multi-step operations
Common Issues and Solutions
"CallTool not implemented" errors
- This means the MCP client is not properly attached to the service
- Check
core_service_listto see if the service shows a client - The fix involves ensuring
GetServiceData()returns the MCP client
Service shows as unhealthy
- Check logs in the mcp-prometheus TUI (if available)
- Use
core_service_statusfor detailed information - Try
core_service_restartto recover
Workflow validation fails
- Use
core_workflow_validateto check syntax - Ensure tool names exist (check with
mcp_mcp-debug_list_tools) - Verify argument schemas match the tool requirements
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- yesterday First seen · 62 lines · 486 tokens per session scan A 438fcf3ca448
mcp-debugging is a cursor rule published in the GitHub repository giantswarm/mcp-prometheus (10 stars, last pushed 2d ago), licensed Apache-2.0. It adds 486 tokens to every session, about $0.0024 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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