prompt-flamegraph

Lightweight, dependency-free prompt context flamegraph generator for LLMs.

What it does

prompt-flamegraph takes a structured prompt (system prompt, tools, RAG context, chat history) and shows you where the tokens go, in an interactive flamegraph.

It is intentionally lightweight: no proxy, no server, no dashboard, no telemetry. One function call, one output file.

Install

pip install prompt-flamegraph

Extras:

pip install prompt-flamegraph[tiktoken]   # accurate OpenAI-style token counts
pip install prompt-flamegraph[rich]       # prettier terminal output

Quick start

from prompt_flamegraph import profile_prompt

prompt = {
    "system_prompt": "You are a helpful coding assistant.",
    "tools": ["..."],
    "rag_context": {"doc_1": "..."},
    "chat_history": ["..."],
}

profile_prompt(prompt, output="context.html")

Open context.html in your browser.

CLI

# HTML flamegraph
prompt-flamegraph prompt.json -o context.html --cost 1.5e-6

# Terminal bar chart
prompt-flamegraph prompt.json --terminal

# Diff between two prompts (green = added, red = removed, orange = changed)
prompt-flamegraph v1.json --diff v2.json -o diff.html

# SVG or Markdown export
prompt-flamegraph prompt.json --format svg -o context.svg
prompt-flamegraph prompt.json --format md -o context.md

# Demo
prompt-flamegraph --demo --cost 1.5e-6

Features

• Pure Python, no required dependencies.
• Optional tiktoken support.
• Pluggable tokenizer.
• Cost estimation.
• Token waste detection: duplicates, oversized RAG, long history, too many tools.
• Prompt diff: compare two prompts and visualize token changes.
• Terminal output: colored ASCII/Rich bar chart.
• Export formats: HTML, SVG, Markdown.
• Works with nested dict, list and str structures.

API

profile_prompt(data, output, title, tokenizer, cost_per_token, detect_waste, width, height)

Build and render a prompt flamegraph to HTML.

diff_prompts(v1, v2, output, title, ...)

Render a diff flamegraph between two prompts.

detect_waste(tree)

Analyze a tree and return a WasteReport with findings.

build_tree(data, name, tokenizer)

Build the internal token tree without rendering.

Source

https://github.com/fjjjuv/prompt-flamegraph

License

This project is licensed under the GNU General Public License v3.0 or later.

See the LICENSE file for details.