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 skills/microsoft/debugmcp/debug-livenpx skills add microsoft/DebugMCP --skill debug-livegit clone --depth 1 https://github.com/microsoft/DebugMCPWhat 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 | $0.00084 | $0.02754 |
| Opus 5 | $0.00042 | $0.01377 |
| Sonnet 5 | $0.00017 | $0.00551 |
| Haiku 4.5 | $0.00008 | $0.00275 |
Grade A, and why
debug-live 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 2d ago.
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 — 275 lines — stays where its author put it; the contents beside it link to each section on GitHub.
DebugMCP — Interactive Debugging Skill
This skill teaches an agent how to use the DebugMCP MCP server effectively. The MCP server itself exposes only tools (with brief, behavioral descriptions); the workflow, root cause analysis framework, and language-specific guidance live here.
The
allowed-toolslist above uses the tool names registered by the DebugMCP MCP server. Some runtimes namespace MCP tools (e.g.mcp__debugmcp__start_debugging); adapt as needed.
When to invoke this skill
Invoke this skill as the first investigation step whenever you would otherwise guess at runtime behavior:
- Any reported bug, failing test, exception, or unexpected output.
- A variable holds an unexpected
null/undefined/ wrong type / wrong value. - A function returns something the caller didn't expect.
- A code path executes (or fails to execute) when you didn't predict it would.
- You're about to read a large amount of code "trying to figure out what happens at runtime."
Core workflow
- Set a starting breakpoint. Use
add_breakpointwith the file path and the 1-based line number you want to pause on. Place it at the earliest point that's still relevant to the suspected issue. - Optionally add strategic breakpoints. Decision points, error-handling branches, data boundaries (where input enters, where output is produced).
- Start the session. Call
start_debuggingwith the source file path. For a single test, passtestName; the server routes through VS Code's Testing API so test runners likedotnet test/pytest/jestwork correctly. The call returns when the program either hits a breakpoint (stopped) or runs to completion without pausing (terminated). - Navigate and inspect. Use
step_over,step_into,step_out,continue_executionto move through code. Usepause_executionto interrupt a freely-running program (e.g. a busy loop or embedded target) when there is no breakpoint to stop at. Uselist_variable_namesto see what is in scope (names and types only, no values), thenget_variables_valueswith the specificvariableNamesyou care about, andevaluate_expressionto test hypotheses live (call methods, read properties, run list comprehensions, etc.).
What ships with it
7 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 2d ago First seen · 275 lines · 84 tokens per session scan A e6de8c2a8f51
debug-live is a skill published in the GitHub repository microsoft/DebugMCP (487 stars, last pushed 8d ago), licensed MIT. It adds 84 tokens to every session and 2,754 once invoked, about $0.0004 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 2026-08-30.
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