A tool for working with Langfuse, a service that records and evaluates how language-model applications run. It can use the Langfuse API to access traces, prompts, datasets, scores, sessions, and other stored data, as well as its documentation.

Use it to query or change Langfuse resources through the command line, look up integration and SDK instructions, and investigate language-model application records.

It gives an agent a defined way to inspect Langfuse data and learn how Langfuse integrations work. It also requires checking the connection and credentials before attributing missing data to the application.

langfuse — Skill for Claude Code and Codex by KonghaYao: A tool for working with Langfuse, a service that…

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/konghayao/peri/langfuse

Any agent

npx skills add KonghaYao/peri --skill langfuse

Clone the repo

git clone --depth 1 https://github.com/KonghaYao/peri

Made for: Claude Code, Codex.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/konghayao/peri/langfuse.svg)](https://agentmods.dev/skills/konghayao/peri/langfuse)

Your own site

<a href="https://agentmods.dev/skills/konghayao/peri/langfuse"><img src="https://agentmods.dev/badge/skills/konghayao/peri/langfuse.svg" alt="Measured on agentmods" height="20"></a>

Per session 100 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 5,031 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.

Model	Per session	Once invoked
Fable 5	$0.00100	$0.05031
Opus 5	$0.00050	$0.02516
Sonnet 5	$0.00020	$0.01006
Haiku 4.5	$0.00010	$0.00503

Measured 5d ago against content hash 9b26f3f64fe1, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

langfuse 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 5d ago.

The scan reads SKILL.md. This mod also ships 11 executable files (scripts/analyze.ts, scripts/daily-report.ts, scripts/lib.test.ts, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

- Bash(curl *langfuse.com/*)

.claude/skills/langfuse/SKILL.md · 410 lines

How it starts

The opening of the file, as written. The whole thing — 410 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Langfuse

1. Langfuse API via CLI

Use langfuse-cli to interact with the full Langfuse REST API. Run via bunx (auto-loads .env):

bunx langfuse-cli api --help                              # 列出所有 resources
bunx langfuse-cli api <resource> --help                     # List actions for a resource
bunx langfuse-cli api <resource> <action> --help            # Show args for an action
bunx langfuse-cli api <resource> <action> [options]         # Execute

Credentials

bunx automatically loads .env. Ensure it contains:

LANGFUSE_PUBLIC_KEY=pk-lf-...
LANGFUSE_SECRET_KEY=sk-lf-...
LANGFUSE_HOST=https://cloud.langfuse.com  # Required

If credentials are missing, ask the user to add them to .env. Do not ask to paste keys in chat.

CLI Preflight and Query Integrity

Before attributing missing or malformed data to application behavior:

Confirm LANGFUSE_HOST or LANGFUSE_BASE_URL is set, credentials are present, and the selected host returns JSON rather than an HTML fallback. Never print credentials or authorization headers.
Discover the installed CLI schema with bunx langfuse-cli api --help and resource/action --help; resource names vary by CLI version, so do not assume observations-v2s or another historical alias exists.
For list endpoints, inspect pagination metadata and fetch every required page. The public API page limit is 100; a single page is not proof of completeness.
Record the requested field projection. If input/output fields were not requested or returned by the selected endpoint, report them as not inspected, not null or missing.
Stop business-level diagnosis on host/auth/schema failure. A 401, unsupported resource, HTML response, or truncated page set is a query precondition failure, not evidence about the trace producer.

CLI Tips

Use --json for machine-readable output
Use --curl to preview HTTP request without executing
Discover resources/actions with --help; do not hard-code version-specific v2 aliases
Prefer the bundled scripts for traces and observations because they implement the current public endpoints and pagination

Read the full file on GitHub · 410 lines

Files

What ships with it

19 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.

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.

5d ago First seen · 410 lines · 100 tokens per session scan A 9b26f3f64fe1

Subscribe to this mod's changes

langfuse is a skill published in the GitHub repository KonghaYao/peri (160 stars, last pushed today), licensed Apache-2.0. It adds 100 tokens to every session and 5,031 once invoked, about $0.0005 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.

Analytics and metrics GLM acp claude-code coding-agent deepseek mcp

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langfuse