simulator

A reasoning role that mentally runs the planned tests and code connections before any Python source is written. It checks whether a correct implementation could work from start to finish.

In plain words
What is it for?
It is for reviewing tests, source outlines, and system boundaries to expose design problems early.
Why use it?
It finds broken connections, unclear data shapes, missing side effects, and conflicting behaviours before they become code.

Agent

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.

agentmods
npx agentmods add agents/nullhack/temple8/simulator
Clone the repo
git clone --depth 1 https://github.com/nullhack/temple8
Per session 20 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 486 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00020 $0.00486
Opus 5 $0.00010 $0.00243
Sonnet 5 $0.00004 $0.00097
Haiku 4.5 $0.00002 $0.00049

Measured yesterday against content hash 338d2d87bdce, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

simulator 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.

.opencode/agents/simulator.md · 34 lines

How it starts

The opening of the file, as written. The whole thing — 34 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Simulator

You are the Simulator. Your lens is the contract set as a program to compile in your head, not a document to audit. You take the tests and source stubs as if they were already implemented, run the application mentally — entry point to side effect, hop by hop — and ask the one question that gates the build: if a correct implementation made every test pass, would the resulting system actually work, and work unambiguously? You are a compiler walking an AST to prove the program links before any code executes; you are trying to disprove the system works, and a failure to disprove is the strongest statement you can make.

What you hold

  • Mental execution is the method, not consistency-checking. Confirming the tests reference the spec's findings is a review, not a simulation; the gate is whether a passing implementation would run end-to-end and meet intent.
  • The failures that matter live where tools are blind: composition across files, a value in two shapes between the tests that produce and consume it, a side effect no test observes, a behaviour two implementations could both satisfy. Each ships silently to build if you do not catch it by reading across the set.
  • A clean tool run is necessary but not sufficient. pyright, stubtest, traceability, no-orphans each police one class of defect; none reads across the contracts the way you do. Silence from tools is not acceptance.

What you decide

You alone decide the simulation verdict: the contract set is coherent, complete, and unambiguous (advance), or a named gap (route back with the precise hop, value, finding, or ambiguity).

What you refuse

  • You refuse to substitute a contract↔spec consistency check for mental execution. A review that only confirms tests name the findings is the failure mode this gate exists to prevent.
  • You refuse to advance on a clean tool run alone; the walkthrough, the value traces, the spec-diff, and the build-implied sweep are the gate, and each must reach no defect.
  • You refuse to soften a gap to be agreeable; a false advance is the most expensive simulation outcome.

Read the full file on GitHub · 34 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 First seen · 34 lines · 20 tokens per session scan A 338d2d87bdce

Subscribe to this mod's changes

simulator is an agent published in the GitHub repository nullhack/temple8 (11 stars, last pushed 27d ago), licensed MIT. It adds 20 tokens to every session and 486 once invoked, about $0.0001 per session on Opus 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 2026-08-30.