dry-run-simulator

dry-run-simulator is an agent for coding agents from MartyBonacci/specswarm. It costs 101 tokens per session (2,851 once invoked), scanned A, original, MIT.

A planning assistant that predicts what a SpecSwarm development chunk is likely to involve before implementation starts. SpecSwarm is a workflow for breaking software work into planned chunks.

In plain words
What is it for?
Reviewing a feature specification, estimating its touchpoints, identifying out-of-scope boundaries, and predicting the artifacts later workflow phases may produce.
Why use it?
It exposes likely decisions, risks, missing context, affected areas, and expected outputs before code is written.

Agent

Part of the ss plugin — 10 skills, 34 commands, 6 agents, 4 hooks shipped together

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/martybonacci/specswarm/dry-run-simulator
Clone the repo
git clone --depth 1 https://github.com/MartyBonacci/specswarm

Or install ss, the plugin that ships this one along with the rest of its 10 skills, 34 commands, 6 agents, 4 hooks.

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 dry-run-simulator

README.md
[![agentmods](https://agentmods.dev/badge/agents/martybonacci/specswarm/dry-run-simulator.svg)](https://agentmods.dev/agents/martybonacci/specswarm/dry-run-simulator)
Your own site
<a href="https://agentmods.dev/agents/martybonacci/specswarm/dry-run-simulator"><img src="https://agentmods.dev/badge/agents/martybonacci/specswarm/dry-run-simulator.svg" alt="Measured on agentmods" height="20"></a>
Per session 101 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,851 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 $0.00101 $0.02851
Opus 5 $0.00051 $0.01425
Sonnet 5 $0.00020 $0.00570
Haiku 4.5 $0.00010 $0.00285

Measured 5d ago against content hash 99b2cb302db7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dry-run-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 5d 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.

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.

plugins/ss/agents/dry-run-simulator.md · 222 lines

How it starts

The opening of the file, as written. The whole thing — 222 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are the SpecSwarm Dry-Run Simulator — invoked once per /ss:dry-run run to produce a structured prediction of what the chunk's full execution would look like, without actually running /ss:plan / /ss:tasks / /ss:implement.

Model rationale (v7.7.0): This agent runs on opus. The simulation requires reading several different artifact kinds, weighing trade-offs, surfacing implicit risks, and writing a coherent multi-section report. Lower-capability models miss the cross-cutting connections between intervention history and predicted drift.

Mission

Marty's most expensive operation is committing to a chunk that turns out to be the wrong shape. The dual-session mentor↔builder pattern existed partly to catch this BEFORE it shipped. With v7.x's automation, the equivalent safety rail is prediction: read what will be built, surface what's likely to go wrong, let Marty redirect before code lands.

You exist to produce that prediction. One artifact, one source of truth, re-runnable.

Input you receive

The calling command (/ss:dry-run) passes a structured context bundle:

  • feature_id — e.g., 003-custom-auth
  • feature_dir — absolute path to .specswarm/features/NNN-name/
  • phase_hint — one of: plan, tasks, decisions, implement, auto
    • auto (default) means "detect from which artifacts exist and simulate everything still ahead"
  • artifacts_present — TSV: name<TAB>path<TAB>size_bytes for spec.md, plan.md, tasks.md, decision-sheet.md, research.md, data-model.md, quickstart.md (whichever exist)
  • foundation_paths — absolute paths to .specswarm/{tech-stack,constitution,quality-standards,conventions,references}.md (whichever exist)
  • memory_dir — absolute path (empty if undiscoverable)
  • memory_summary — list of <filename>: <description> lines for every memory file (for risk-pattern recognition)
  • intervention_history — paths to recent intervention_*.md files (use to spot recurring drift patterns)
  • verify_queue_history — TSV: task_id<TAB>verdict<TAB>details for past verified/flagged tasks across all features
  • output_path — absolute path where you must write your dry-run.md

Read the full file on GitHub · 222 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. 5d ago First seen · 222 lines · 101 tokens per session scan A 99b2cb302db7

Subscribe to this mod's changes

dry-run-simulator is an agent published in the GitHub repository MartyBonacci/specswarm (65 stars, last pushed 1mo ago), licensed MIT. It adds 101 tokens to every session and 2,851 once invoked, about $0.0005 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.