neqsim-platform-modeling

neqsim-platform-modeling is a skill for Claude Code, Codex from equinor/neqsim. It costs 96 tokens per session (12,993 once invoked), scanned A, original, Apache-2.0.

A guide to building complete NeqSim simulations of oil and gas production platforms from design documents and operating data. It covers the connected equipment on the platform's topside processing system.

In plain words
What is it for?
Use it to model separation stages, recompression trains, recycles, fluids, equipment responses, and other parts of a platform process flowsheet.
Why use it?
It provides a consistent structure for handling inputs, running the simulation, and returning typed results across large process models.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to model separation stages, recompression trains, recycles, fluids, equipment responses, and other parts of a platform process flowsheet.

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Install with agentmods
npx agentmods add skills/equinor/neqsim/neqsim-platform-modeling
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 --skill neqsim-platform-modeling
Clone the repo
git clone --depth 1 https://github.com/equinor/neqsim

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.

agentmods badge for neqsim-platform-modeling

README.md
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Your own site
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Your own site · 80×15
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Per session 96 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 12,993 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium analysis-evasion · line 1
    Suspicious Unicode normalization or mixed-script content
    Fix: Review the flagged content for security risks. Ensure no credentials, secrets, or sensitive data are exposed.
How audits are shown
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00096 $0.12993
Opus 5.5 $0.00038 $0.05197
Sonnet 5.5 $0.00019 $0.02599
Haiku 4.5 $0.00010 $0.01299

Measured yesterday against content hash f12d02b506c9, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

neqsim-platform-modeling 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 yesterday.

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.

.github/skills/neqsim-platform-modeling/SKILL.md · 1,165 lines

How it starts

The opening of the file, as written. The whole thing — 1,165 lines — stays where its author put it; the contents beside it link to each section on GitHub.

NeqSim Production Platform Modeling

Comprehensive patterns for building complete topside process simulations from platform design documents. Derived from production-grade models of 15+ NCS platforms (Åsgard A/B, Troll A/B, Grane, Castberg, Martin Linge, Gudrun, etc.) in the NeqSim-dev-environment.


1. Architecture Overview

1.1 Standard Model Structure

Every production platform model follows the same architecture:

ProcessInput (pydantic) → simulate() function → ProcessSystem → calc_result() → ProcessOutput (pydantic)
Component Purpose Pattern
ProcessInput All operating conditions as typed fields Pydantic BaseModel with 50-100+ fields
simulate() Builds and runs the ProcessSystem Single function, 500-1500 lines
calc_result() Extracts structured results from solved system Calls simulate(), builds ProcessOutput
ProcessOutput All results in typed, serializable format Pydantic BaseModel with response objects
neqsim_responses.py Helper functions to extract equipment data get_separator_response(), get_compressor_response(), etc.
pydantic_classes.py Shared response types CompressorResponse, SeparatorResponse, HeaterResponse, etc.

1.2 Two Execution Strategies

Strategy A — Manual Iteration (ASGA pattern):

NUMBER_OF_ITERATIONS = 25

operations = ProcessSystem()
# ... build entire flowsheet ...
for _ in range(NUMBER_OF_ITERATIONS):
    operations.run_step()

Best for: models with many recycles that need controlled convergence.

Strategy B — Single Blocking Run (Martin Linge pattern):

operations = ProcessSystem()
# ... build entire flowsheet ...
thread = operations.runAsThread()
thread.join(config.SYNC_REQUEST_TIMEOUT_MS)  # e.g., 120000 ms

if thread.isAlive():
    thread.interrupt()
    raise CalculationTimeout("Timed out")

Best for: models with few recycles where NeqSim's internal solver handles convergence.

Read the full file on GitHub · 1,165 lines

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.

  1. yesterday Changed · +7 lines f12d02b506c9
  2. 9d ago Changed · +43 lines bafead9e0f0f
  3. 20d ago Changed · -13 tokens per session ed0142afbbfe
  4. 1mo ago Changed · +13 lines 6b3deb630f76
  5. 1mo ago First seen · 1,102 lines · 109 tokens per session scan A 7d92fc9e683b

Subscribe to this mod's changes

neqsim-platform-modeling is a skill published in the GitHub repository equinor/neqsim (156 stars, last pushed today), licensed Apache-2.0. It adds 96 tokens to every session and 12,993 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 2026-09-03.

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