Borrowing it
Nothing to install: this file belongs to vega/vegafusion. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/vega/vegafusion/main/CLAUDE.mdgit clone --depth 1 https://github.com/vega/vegafusionWrote 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/instructions/vega/vegafusion/claude-md)<a href="https://agentmods.dev/instructions/vega/vegafusion/claude-md"><img src="https://agentmods.dev/badge/instructions/vega/vegafusion/claude-md.svg" alt="Measured on agentmods" 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 | $0.00407 | $0.00407 |
| Opus 5 | $0.00204 | $0.00204 |
| Sonnet 5 | $0.00081 | $0.00081 |
| Haiku 4.5 | $0.00041 | $0.00041 |
Grade C, and why
vegafusion CLAUDE.md scanned grade C with 2 findings 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 7d 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.
Downloads and executes remote codehighSupply chain
curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh # Rust Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh # Rust What it actually says
CLAUDE.md
VegaFusion optimizes Vega visualizations by pre-computing data transforms using Apache DataFusion. This enables scalable charting with the Vega ecosystem.
Architecture
Crate dependency chain:
- vegafusion-common → vegafusion-core → vegafusion-runtime → (python, wasm, server)
DataFusion was chosen for columnar computation and query optimization capabilities.
Development Setup
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh # Rust
curl -fsSL https://pixi.sh/install.sh | bash # Pixi (manages all else)
Key commands: pixi run test-rs-runtime, pixi run dev-py, pixi run build-wasm
Critical Constraints
IMPORTANT: Feature flag conflicts
httpandhttp-wasmare mutually exclusive (usehttp-wasmfor WASM builds)tonicrequiresprotofeature
IMPORTANT: Proto changes require Python rebuild
- Proto files in
vegafusion-core/src/proto/auto-generate during build - After proto changes:
pixi run dev-py
IMPORTANT: Error handling
- Use
.with_context(|| "message")pattern (see vegafusion-common for details)
Testing
Tests compare VegaFusion output against VegaJS reference implementation.
- Float tolerance: 1e-6
- Test specs:
vegafusion-runtime/tests/specs/ - VegaJS runtime:
vegafusion-runtime/tests/util/vegajs_runtime/
Common Debugging
Proto compilation issues:
- Check stderr for protoc errors
- Verify
protobuf-srcfeature if system protoc unavailable
Python "symbol not found":
- Stale build - run
pixi run dev-py
VegaJS test crashes:
- Check
npm installcompleted intests/util/vegajs_runtime/
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.
- 7d ago First seen · 52 lines · 407 tokens per session scan C 325e108775d9
vegafusion CLAUDE.md is an instructions file published in the GitHub repository vega/vegafusion (422 stars, last pushed 5mo ago), licensed BSD-3-Clause. It adds 407 tokens to every session, about $0.0020 per session on Opus 5. A static security scan graded it C with 2 findings (downloads and executes remote code, 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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