neqsim: Instructions file for Codex

AGENTS.md

neqsim AGENTS.md is an instructions file for Codex, OpenCode from equinor/neqsim. It costs 3,183 tokens per session, scanned A, original, Apache-2.0.

A repository instruction file for NeqSim coding agents. It documents the project layout and rules such as Java 8 compatibility, Log4j2 logging, and Spotless code formatting.

In plain words
What is it for?
Use it as the starting guidance whenever an agent reads, changes, tests, or formats code in the NeqSim repository.
Why use it?
It prevents agents from using newer Java features, unsuitable output statements, or code that fails the project's formatting checks.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md. Also seen: mentions subagents; mentions Claude Code; mentions Codex.

This is equinor/neqsim's own configuration. It tells Codex and OpenCode how to work on neqsim itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything neqsim configures →

Reuse

Borrowing it

Nothing to install: this file belongs to equinor/neqsim. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/equinor/neqsim/master/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/equinor/neqsim

Made for: Codex, OpenCode.

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.

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README.md
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Per session 3,183 This file is loaded in full into every session.
When invoked 3,183 The same file — it is already loaded in full.
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.03183 $0.03183
Opus 5.5 $0.01273 $0.01273
Sonnet 5.5 $0.00637 $0.00637
Haiku 4.5 $0.00318 $0.00318

Measured today against content hash 86ffe3e37522, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

neqsim AGENTS.md 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 today.

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.

AGENTS.md · 165 lines

How it starts

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

NeqSim — Agent Instructions

Read automatically by VS Code Copilot, OpenAI Codex, Claude Code and other agents. This file is kept short on purpose because it is resent on every model call. It is already in your context — do not read_file it. Detail lives in:

  • docs/development/AGENT_REFERENCE.md — full workflow, results.json schema, Automation API, code patterns, key paths, JavaDoc and documentation rules. Search it for the heading you need; never read it whole.
  • Skills in .github/skills/ (find them with uv run --project devtools --locked devtools/skill_search.py "<topic>").
  • CONTEXT.md — 60-second repo map. docs/development/CODE_PATTERNS.md — starters.

Hard constraints (CI fails otherwise)

  • Java 8 everywhere, tests included. Never var, List.of/Set.of/Map.of, String.repeat (use StringUtils.repeat), isBlank/strip/lines (use trim()), text blocks, records, pattern-matching instanceof, Optional.isEmpty().
  • Logging: Log4j2 only (private static final Logger logger = LogManager.getLogger(X.class);, parameterized logger.info("{}", v)). Never System.out/err.println, also not in tests or examples.
  • Spotless: after creating or editing ANY .java file run .\mvnw.cmd spotless:apply (Linux/Mac ./mvnw), then git add. CI runs spotless:check. Never --no-verify.
  • JavaDoc on every class and method, private included: description, @param for each parameter, @return, @throws for every declared exception, class @author/@version. HTML5: <table> needs <caption>, no summary=; @see only with Java references; no </p> after </ul>/</ol>; no -> or raw > in JavaDoc (&gt;). Check with mvnw javadoc:javadoc. Spotless/Checkstyle/JavaDoc failures: neqsim-code-hygiene skill.
  • Serializable classes: non-serializable fields (Function, Consumer, Thread, JDBC, interpolators) must be private transient (SpotBugs SE_BAD_FIELD).
  • Verify APIs before use: find the class, read constructor/method signatures, never assume convenience overloads, enum locations or getter arguments.
  • Discover across all functionality: in a source checkout use uv run --project devtools --locked devtools/capability_search.py "<task or API>" --json. It returns current source types, workflow agents/skills, guides and test references; load only the relevant skill sections. In plugin/MCP-only sessions use runtime discovery. Read the discovery guide before declaring functionality absent. Routing coverage and test references do not establish qualification.
  • Agent/MCP coverage: src/main/resources/neqsim/mcp/engineering-coverage.json is a generated snapshot, not a source of truth. After Java formatting or agent/skill mapping changes, regenerate it with uv run --project devtools --locked devtools/build_engineering_coverage.py and stage the output. For merge conflicts, resolve source and registry conflicts first, then regenerate and git add this file. Never hand-merge its JSON or combine branch copies; neither produces a valid inventory of the merged sources. CI rebuilds and validates the snapshot, then commits changed output back to same-repository PR branches and master when permissions and branch protection allow. Fork PRs remain validation-only. Register new engineering operations with routes and evidence; source presence is not validation.
  • AI workflow names: GitHub Actions workflows for agent, skill, MCP, task, or research tooling MUST use ai-<purpose>.yml in lowercase kebab-case, directly in .github/workflows/. Categorize by primary responsibility: publishing MCP artifacts still uses publish-. Follow .github/WORKFLOWS.md; update filename references when renaming and preserve required-check names unless their consumers have been reviewed.
  • Documentation code must be test-verified: every Java/Python snippet in docs gets a JUnit test (e.g. DocExamplesCompilationTest) that is run and passes before the doc is done.
  • Notebooks must be executed end to end (NeqSim Runner by default); unexecuted = incomplete.
  • Linux-only engines (FluidMagic, OpenFOAM, OPM Flow) need Docker Desktop/WSL2 on Windows; report a missing runtime as a blocker, never skip silently.
  • FluidMagic is Equinor-internal, not on PyPI (enterprise agents/skills only): running it needs the private repo equinor/FluidMagic (own GitHub SSO; gh repo clone equinor/FluidMagic, pip install -e FluidMagic/fluidmagic). Never pip install fluidmagic; if import fluidmagic fails, tell the user how to get it and fall back to the offline hand-off.

Read the full file on GitHub · 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. today Changed · +6 lines · +109 tokens per session 86ffe3e37522
  2. 5d ago Changed · +4 lines · +95 tokens per session 6eeb9b0f72fd
  3. 6d ago Changed · +2 lines · +48 tokens per session aa72a227a4a2
  4. 7d ago Changed · +9 lines · +202 tokens per session 30d9c6d80fa8
  5. 8d ago Changed · +28 tokens per session def5ff5f8e22
  6. 10d ago Changed · +5 lines · +105 tokens per session 65b836cc93ac
  7. 20d ago Changed · +12 lines · +263 tokens per session 33a729e61f9a
  8. 28d ago Changed · -1,391 lines · -21,600 tokens per session e2aa4697a7c8
  9. 1mo ago Changed · +30 lines · +453 tokens per session f75857e14502
  10. 1mo ago First seen · 1,488 lines · 23,480 tokens per session scan A ef22de8383a4

Subscribe to this mod's changes

neqsim AGENTS.md is an instructions file published in the GitHub repository equinor/neqsim (158 stars, last pushed today), licensed Apache-2.0. It adds 3,183 tokens to every session, about $0.0127 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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