Langfuse Agent Skill

Interact with Langfuse and access its documentation.

Context cost
16.5k tokensestimated from the bundle, loaded when it triggers
Bundle
12 files · 65.9 kBtext throughout, nothing executable
Licence
not declarednone named by its author
Last change
—no release on file
Servers it uses
Noneruns standalone

What it does

Interact with Langfuse and access its documentation. Use when needing to (1) query or modify Langfuse data programmatically via the CLI — traces, prompts, datasets, scores, sessions, and any other API resource, (2) look up Langfuse documentation, concepts, integration guides, or SDK usage, or (3) understand how any Langfuse feature works. This skill covers CLI-based API access (via npx) and multiple documentation retrieval methods.

What this skill changes about the agent has not been set out here as a list. Its SKILL.md, shown below, says it in the author’s own words.

analyticsdocumentation

The skill itself

A skill is instructions the model reads, so you can see what you are getting: below is the start of its SKILL.md. The front matter loads with every session, the body loads when the skill triggers, and the whole file comes with the install.

SKILL.md8.1 kB · preview
--- name: langfuse allowed-tools: - WebFetch(domain:langfuse.com) - Bash(curl *langfuse.com/*) - Bash(npx langfuse-cli api __schema *) - Bash(npx langfuse-cli api * --help *) - Bash(npx langfuse-cli api * list *) - Bash(npx langfuse-cli api * get *) - Bash(bunx langfuse-cli api __schema *) - Bash(bunx langfuse-cli api * --help *) - Bash(bunx langfuse-cli api * list *) - Bash(bunx langfuse-cli api * get *) ---
17# Langfuse
18
19This skill helps you use Langfuse effectively across all common workflows: instrumenting applications, migrating prompts, debugging traces, and accessing data programmatically.
20
21## Core Principles
22
23Follow these principles for ALL Langfuse work:
24
251. **Documentation First**: NEVER implement based on memory. Always fetch current docs before writing code (Langfuse updates frequently) See the section below on how to access documentation.
262. **CLI for Data Access**: Use langfuse-cli when querying/modifying Langfuse data. See the section below on how to use the CLI.
273. **Best Practices by Use Case**: Check the relevant reference file below for use-case-specific guidelines before implementing
284. **Use latest Langfuse versions**: Unless the user specified otherwise or there's a good reason, always use the latest version of Langfuse SDKs/APIs. Even if you're only creating a plan for another agent to execute, be explicit about the exact version to use.
295. **If you guide the user through UI** and are unsure about a label or location, inspect the user’s screenshots or ask to see the relevant screen. Do not assume UI labels have the exact same names as API, SDK, or CLI fields.
30
31
32## Use case specific references
33
34- instrumenting an existing function/application: references/instrumentation.md
35- migrating prompts from a codebase into Langfuse: references/prompt-migration.md
This is a preview of SKILL.md. Download or install the skill to get the whole thing.
In the file
SKILL.md1,137 words
Files12
Licencenot declared
Why you can read it

Nothing in a skill executes. The client loads the text and the model follows it, so a skill can be audited the way a runbook is — by reading it.

What it costs in context

Skills are not billed by the call. They are paid for in context: every token the instructions occupy is a token your code, your diff and your conversation cannot use. Here is what this one takes and when it takes it.

≈220
always loaded
The name and description, so the model knows the skill exists and when to reach for it.
16,255
on trigger
The instruction body and 11 supporting files, read only when the skill fires.
8.2%
of a 200k window
Ten skills this size would take about 82% of the window before you open a file.
050k100k150k200k context window

16.5k tokens, estimated from the bundle at four bytes to the token, held for the rest of the session once it triggers. Heavy. Teams tend to install this one per project rather than globally, and load it only when the job comes up.

Servers bill, skills cost

A server charges by the month. A skill charges once per session, in context, and then keeps charging it for as long as the session lives.

Before and after

The same question, put to the same model twice: once as it comes, and once with these instructions loaded.

No worked example has been published for this skill yet.

The procedure it runs

The procedure has not been set out here step by step. It is in the body of its SKILL.md: the start of it is shown above, and the whole file comes with the install.

Prose, not code

These steps are written for a model to follow, not executed by a runtime. It can still be told to skip one, and it will say so when it does.

Servers it uses

None. This skill calls no MCP servers at all.

Everything it needs is in the instructions, so it works in a project with nothing connected — the model reads the file and changes how it works with what it can already reach.

It asks for pages to be fetched through your client’s own network access. Whether it writes files is not declared.

What it asks for
Writes filesnot declared
Network accessyes

Read from the allowed-tools line of this skill’s own SKILL.md. It also asks for Bash, which could do either, so what is not named there is not ruled out. A skill grants no permissions of its own — it can only ask for tools your client already has.

What it will not do

Every skill is narrow, and the useful ones say where they stop. These are the jobs this one is the wrong tool for.

What this skill is not for has not been published here. Nothing is implied by that: it is a section the author has not filled in.

What is in the bundle

12 files, 65.9 kB on disk. A bundle is text throughout: the instructions the model reads, plus the templates it fills in.

  • SKILL.md8.1 kB
  • references/ci-cd.md3.1 kB
  • references/cli.md2.2 kB
  • references/error-analysis.md4.8 kB
  • references/instrumentation.md10.1 kB
  • references/judge-calibration.md11.1 kB
  • references/prompt-engineering.md2.8 kB
  • references/prompt-migration.md5.2 kB
  • references/skill-feedback.md2.2 kB
  • references/trace-evaluator-upgrade.md5.4 kB
  • references/user-feedback.md4.1 kB
  • references/v4-project-migration.md6.8 kB
What is not in it

No dependencies and nothing executable: a skill is text the agent reads, so the bundle is 12 files you can review in full before installing.

Install

Installing copies the bundle into your project. Nothing runs at install time — the files sit on disk until the model reads them.

# Langfuse · 16.5k tokens when loaded · macOS, Linux mkdir -p .claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/karanmrn-langfuse/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/langfuse" ] && { [ ! -e .claude/skills/langfuse ] || { mv .claude/skills/langfuse "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/langfuse" .claude/skills/ && echo "Installed .claude/skills/langfuse"
On Windows, or any OS with Node 20+
npx mcprush@latest skill add karanmrn/langfuse

Windows PowerShell says 'running scripts is disabled on this system'? Run Set-ExecutionPolicy -Scope CurrentUser RemoteSigned once, or type npx.cmd instead of npx (codex.cmd, gemini.cmd, grok.cmd likewise). PowerShell 7 needs neither. Writes to .claude/skills/langfuse/ in the current project. For every project instead, run mkdir -p ~/.claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/karanmrn-langfuse/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/langfuse" ] && { [ ! -e ~/.claude/skills/langfuse ] || { mv ~/.claude/skills/langfuse "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/langfuse" ~/.claude/skills/ && echo "Installed ~/.claude/skills/langfuse" (macOS, Linux) — or add --global to the npx line. The curl line replaces .claude/skills/langfuse/ only after the download succeeds, so files left there by another skill of the same name, or by an older release, do not mix in. A copy already there is moved aside, not deleted, and the line prints where.

Which clients pick it up on their own

A skill is a folder of text. Most of these read a skills folder and pick it up without being told; the rest take the same folder another way — an upload in the app, a parameter on an API call — and then choose it by its description just the same.

Claude Code.claude/skills/
Claude DesktopCustomize › Skills
ChatGPTSkills › Create › Upload
Cursor.cursor/skills/
VS Code.github/skills/
Codex CLI.agents/skills/
Gemini CLI.gemini/skills/
Grok Build.grok/skills/
Microsoft CopilotSkills › Upload a skill
PerplexityComputer › Skills › Upload a skill
DeepSeek Harness.dsh/skills/
Zed.agents/skills/
Devin Desktop.devin/skills/
Windsurf (legacy).windsurf/skills/
OpenAI Agents SDKInstructions or sandbox Skills
HTTP / APIa request parameter
This release
Versionnot versioned
Publishedno release date on file
PriceFree
Referencekaranmrn/langfuse

Versions

Its author publishes no version number, so there is nothing here to pin to: what you install is the folder as it stands today. Instructions change more often than APIs do — a skill can be rewritten entirely without anything it depends on moving.

Pinning

Nothing to pin to: this skill carries no version number of its own. What you install is what the folder holds on the day you install it.

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