What is neqsim-e300-fluid-io?

A file-handling tool for moving fluid descriptions between Eclipse 300 (E300) files and NeqSim, a software library for fluid and process calculations. It can also add water using the stated public PVTsim parameters.

Use it to read an E300 file into NeqSim, write a NeqSim fluid back to E300, inspect or edit the file layout, or append water to a fluid file.

It avoids manually editing specialised E300 keyword files or rebuilding the same fluid in NeqSim. It also provides a way to add water consistently when preparing a fluid for simulation.

neqsim-e300-fluid-io — Skill for Claude Code and Codex by equinor

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.

Any agent

npx skills add equinor/neqsim-community-skills --skill neqsim-e300-fluid-io

Clone the repo

git clone --depth 1 https://github.com/equinor/neqsim-community-skills

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/equinor/neqsim-community-skills/neqsim-e300-fluid-io/github.svg)](https://agentmods.dev/skills/equinor/neqsim-community-skills/neqsim-e300-fluid-io)

Your own site

<a href="https://agentmods.dev/skills/equinor/neqsim-community-skills/neqsim-e300-fluid-io"><img src="https://agentmods.dev/badge/skills/equinor/neqsim-community-skills/neqsim-e300-fluid-io/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/equinor/neqsim-community-skills/neqsim-e300-fluid-io"><img src="https://agentmods.dev/badge/skills/equinor/neqsim-community-skills/neqsim-e300-fluid-io.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 95 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 2,622 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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 5.1	$0.00095	$0.02622
Opus 5.5	$0.00038	$0.01049
Sonnet 5.5	$0.00019	$0.00524
Haiku 4.5	$0.00010	$0.00262

Measured 1mo ago against content hash 1bdb458d8506, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

neqsim-e300-fluid-io scanned grade A with 0 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 1mo ago.

The scan reads SKILL.md. This mod also ships 5 executable files (examples/build_water_e300.py, src/e300_fluid_io/__init__.py, src/e300_fluid_io/format.py, …), 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/pvt/neqsim-e300-fluid-io/SKILL.md · 217 lines

How it starts

The opening of the file, as written. The whole thing — 217 lines — stays where its author put it; the contents beside it link to each section on GitHub.

E300 Fluid I/O

Use this skill to move fluids between Eclipse 300 (E300) compositional EOS files and NeqSim, and to add water to a fluid or E300 file using the public PVTsim water parameterization.

The skill has two layers:

A pure-Python layer that parses, edits, and writes the E300 keyword format without requiring NeqSim. It is used to inspect files, add water, and produce E300 files that NeqSim can read back.
A NeqSim bridge that wraps neqsim.thermo.util.readwrite.EclipseFluidReadWrite to load E300 files into rigorous NeqSim SystemInterface fluids, add water, and write fluids back to E300.

When to Use

When a task provides an E300 file and needs a NeqSim fluid for simulation.
When a NeqSim fluid must be exported to an E300 file for PVTsim or Eclipse.
When water must be added to a dry fluid using the public PVTsim water parameters (reproducing a PVTsim *_water.e300 file).
When an existing E300 file must be copied with water appended as the last component with a binary interaction parameter of 0.5 against all components.
When a task must document or verify the E300 keyword layout.

Inputs

e300_path: path to an Eclipse E300 file.
add_water: whether to append a water component (H2O).
water_kij: water binary interaction parameter (PVTsim default 0.5).
reservoir_temp_c: reservoir temperature written to the RTEMP keyword.
neqsim_fluid: a NeqSim SystemInterface fluid (for export).

Outputs

neqsim_fluid: a NeqSim fluid created from an E300 file.
e300_file: a written E300 file (with or without water).
e300_string: E300 keyword text for a NeqSim fluid.
E300Fluid: a pure-Python object with component names, EOS parameters, the binary interaction matrix, and the overall composition.

Engineering Method

E300 file format

An E300 file is a keyword text file. Each keyword introduces a value block that is terminated by a /. Lines starting with -- are comments. The keywords this skill reads and writes are:

Read the full file on GitHub · 217 lines

Files

What ships with it

8 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.

1mo ago First seen · 217 lines · 95 tokens per session scan A 1bdb458d8506

Subscribe to this mod's changes

neqsim-e300-fluid-io is a skill published in the GitHub repository equinor/neqsim-community-skills (4 stars, last pushed today), licensed Apache-2.0. It adds 95 tokens to every session and 2,622 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-19.

Scientific

neqsim-e300-fluid-io next to 6 skills from other repositories
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