A repository-scanning workflow for projects that already contain code, often called brownfield projects. It finds Git repositories and manages which ones should provide context during interviews.

Use it to scan for GitHub-hosted repositories, view current defaults, or set the repositories used as interview context.

It removes the need to locate existing projects and choose their defaults manually before repository-based interviews.

brownfield — Skill for Claude Code and Codex by cohemm: A repository-scanning workflow for projects that already contain code…

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 skills/cohemm/prism/brownfield

Any agent

npx skills add cohemm/prism --skill brownfield

Clone the repo

git clone --depth 1 https://github.com/cohemm/prism

Made for: Claude Code, Codex.

Or install prism, the plugin that ships this one along with the rest of its 6 skills, 5 commands, 2 agents, 2 hooks, 1 MCP server.

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/cohemm/prism/brownfield.svg)](https://agentmods.dev/skills/cohemm/prism/brownfield)

Your own site

<a href="https://agentmods.dev/skills/cohemm/prism/brownfield"><img src="https://agentmods.dev/badge/skills/cohemm/prism/brownfield.svg" alt="Measured on agentmods" height="20"></a>

Per session 12 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,109 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.

Model	Per session	Once invoked
Fable 5	$0.00012	$0.01109
Opus 5	$0.00006	$0.00554
Sonnet 5	$0.00002	$0.00222
Haiku 4.5	$0.00001	$0.00111

Measured 4d ago against content hash a4394e4f07ae, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

brownfield 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 4d 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.

skills/brownfield/SKILL.md · 157 lines

How it starts

The opening of the file, as written. The whole thing — 157 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/prism:brownfield

Scan your home directory for existing git repositories and manage default repos used as context in interviews.

In Codex, this same shared workflow is invoked through psm brownfield. The repo skills/brownfield/SKILL.md file remains the canonical source; any installed ~/.codex/skills/prism-brownfield copy is just a managed mirror refreshed by setup.

Usage

/prism:brownfield                # Scan repos and set defaults
/prism:brownfield scan           # Scan only (no default selection)
/prism:brownfield defaults       # Show current defaults
/prism:brownfield set 6,18,19   # Set defaults by repo numbers

Trigger keywords: "brownfield", "scan repos", "default repos", "brownfield scan"

How It Works

Default flow (no args)

Step 1: Scan

Show scanning indicator:

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
  Scanning for Existing Projects...
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Looking for git repositories in your home directory.
Only GitHub-hosted repos will be registered.
This may take a moment...

Implementation — use MCP tools only, do NOT use CLI or Python scripts:

Load the brownfield MCP tool: ToolSearch query: "+prism brownfield"
Call scan+register:
```
Tool: prism_brownfield
Arguments: { "action": "scan" }
```
This scans ~/ for GitHub repos and registers them in DB. Existing defaults are preserved.

The scan response text already contains a pre-formatted numbered list with [default] markers. Do NOT make any additional MCP calls to list or query repos.

Display the repos in a plain-text 2-column grid (NOT a markdown table). Use a code block so columns align. Example:

Scan complete. 8 repositories registered.

 1. repo-alpha                   5. repo-epsilon
 2. repo-bravo *                 6. repo-foxtrot
 3. repo-charlie                 7. repo-golf *
 4. repo-delta                   8. repo-hotel

Include * markers for defaults exactly as they appear in the scan response.

Read the full file on GitHub · 157 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.

4d ago First seen · 157 lines · 12 tokens per session scan A a4394e4f07ae

Subscribe to this mod's changes

brownfield is a skill published in the GitHub repository cohemm/prism (5 stars, last pushed 3mo ago), licensed MIT. It adds 12 tokens to every session and 1,109 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 2026-08-31.

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