langgraph-code-review

A review guide for LangGraph programs, which use connected steps and stored state to run agent workflows.

In plain words
What is it for?
Use it to review StateGraph definitions, nodes, edges, state schemas, checkpointing, and async patterns for mistakes or improvements.
Why use it?
It helps find bugs and design problems in graphs, state handling, checkpoints, and asynchronous code while requiring each finding to be tied to freshly read source code.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/existential-birds/beagle/langgraph-code-review
Any agent
npx skills add existential-birds/beagle --skill langgraph-code-review
Clone the repo
git clone --depth 1 https://github.com/existential-birds/beagle

Made for: Claude Code, Codex.

Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,581 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00056 $0.02581
Opus 5 $0.00028 $0.01290
Sonnet 5 $0.00011 $0.00516
Haiku 4.5 $0.00006 $0.00258

Measured 2d ago against content hash 16a95bb3a5d3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

langgraph-code-review 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 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

result = requests.get(url) # Blocks event loop!
plugins/beagle-ai/skills/langgraph-code-review/SKILL.md · 345 lines

How it starts

The opening of the file, as written. The whole thing — 345 lines — stays where its author put it; the contents beside it link to each section on GitHub.

LangGraph Code Review

When reviewing LangGraph code, check for these categories of issues.

Anti-confabulation (gate 0 — runs before every other gate)

Before issuing any finding — flag a bug, anti-pattern, or improvement — you MUST echo the exact artifact you are judging, quoted from a source you read in this turn:

  • The code finding: its file:line plus the cited code, read freshly now.
  • The graph/state code under review: the StateGraph, node, edge, or state-schema snippet your finding depends on, quoted from the file you just read.

The artifact is the only source of truth. Never infer what you are reviewing from the branch name, the working directory, surrounding files, or recollection. If your mental model differs from the freshly read source, the source wins. A finding issued without a same-turn echo of its target is invalid — emit the echo first, or do not emit the finding.

This gate exists because an LLM under contextual priming will confidently flag code that is not in the file. It runs before the gates below.

Review gates (sequenced)

Complete in order. Each step has an objective pass condition before moving on.

  1. Locate graph code — Search the review scope for StateGraph, compile(, invoke, ainvoke, add_node, add_edge, add_conditional_edges. Pass: a short list of file paths (or explicit “none in scope” after searching).

  2. Map state schema — For each graph state type (TypedDict, BaseModel, etc.), list fields that hold lists, dicts, or messages and whether Annotated + reducers (add_messages, operator.add, …) are present. Pass: every such field is either covered by a reducer pattern below or explicitly flagged as intentional overwrite.

  3. Trace persistence — If interrupts, thread_id, or checkpoint APIs appear, follow them to compile(..., checkpointer=...) and invocation config. Pass: behavior matches the interrupt/checkpointer/thread_id guidance below—or you document a concrete mismatch with file:line.

Read the full file on GitHub · 345 lines

Changes

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.

  1. 2d ago First seen · 345 lines · 56 tokens per session scan A 16a95bb3a5d3

Subscribe to this mod's changes

langgraph-code-review is a skill published in the GitHub repository existential-birds/beagle (79 stars, last pushed 23d ago), licensed Apache-2.0. It adds 56 tokens to every session and 2,581 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 2026-08-30.

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