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 skills add kirill-sviridov/agent-dev-skills --skill debug-langgraph-agentgit clone --depth 1 https://github.com/kirill-sviridov/agent-dev-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/kirill-sviridov/agent-dev-skills/debug-langgraph-agent)<a href="https://agentmods.dev/skills/kirill-sviridov/agent-dev-skills/debug-langgraph-agent"><img src="https://agentmods.dev/badge/skills/kirill-sviridov/agent-dev-skills/debug-langgraph-agent/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/kirill-sviridov/agent-dev-skills/debug-langgraph-agent"><img src="https://agentmods.dev/badge/skills/kirill-sviridov/agent-dev-skills/debug-langgraph-agent.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What 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 5.1 | $0.00061 | $0.02322 |
| Opus 5 | $0.00030 | $0.01161 |
| Sonnet 5 | $0.00012 | $0.00464 |
| Haiku 4.5 | $0.00006 | $0.00232 |
Grade A, and why
debug-langgraph-agent scanned grade A with 1 finding 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 9d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
3. **DNS / firewall** — the LLM provider or proxy is unreachable from the container. `curl <base_url>` from inside the container → the check. How it starts
The opening of the file, as written. The whole thing — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Debug LangGraph Agent
The LangGraph-specific counterpart to
superpowers:systematic-debugging, tuned to LangGraph symptoms. The goal is not to guess but to walk a checklist in the right order and localize the cause.
When to use
- Generated LangGraph code crashes with an error.
- The agent "works" but returns the wrong thing (loses context, loops, branches incorrectly).
- The symptom is unclear ("it just doesn't work").
- Before calling an external code-debugging MCP tool — first narrow the symptom down to one of the categories below.
When NOT to use
- It's not LangGraph code (a flat LLM call / create_agent without a graph — those have different ailments).
- The error is clearly in the code around the agent (FastAPI handler, DB query) — that's ordinary debugging, not a LangGraph specific.
§0. Look at the trace first
Before guessing from the code or classifying the symptom, look at what actually happened:
- LangSmith:
LANGSMITH_TRACING=true(+LANGSMITH_API_KEY) — every run is visible end to end: which nodes executed, with what state on input/output, which tool calls the model made, the full prompts. Half the sections below are resolved by a single glance at the trace. langgraph dev→ Studio: a visual run of the graph + time-travel — rewind to the checkpoint before the failing node, edit state by hand, fork the execution, and see whether the bug disappears.- Without a UI:
graph.get_state_history(config)— programmatic access to the same checkpoints: where it stopped, what was in state at each step.
If the trace is unavailable (no key, prod without LangSmith) — walk the checklist below.
Algorithm: classify the symptom → section
| Symptom | Where to look |
|---|---|
| Messages "get lost" between nodes | §1 State reducer |
| The graph doesn't take the expected branch | §2 Routing |
| A tool "isn't called" / the wrong one is | §3 Tool wiring |
| Hangs on one node / infinite loop | §4 Recursion limit + edges |
KeyError / TypeError in state |
§5 State schema |
| HITL doesn't return control after resume | §6 interrupt/checkpointer |
| The LLM returns "garbage" (not JSON, extra text) | §7 Prompt + structured output |
| A strange error about async / connection closed | §8 Async + checkpointer plumbing |
| Broken after deploy, fine locally | §9 Environment |
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.
- 9d ago First seen · 123 lines · 61 tokens per session scan A 61cd22ab0812
debug-langgraph-agent is a skill published in the GitHub repository kirill-sviridov/agent-dev-skills (2 stars, last pushed 2mo ago), licensed MIT. It adds 61 tokens to every session and 2,322 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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