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.
git clone --depth 1 https://github.com/ralfstrobel/agentic-brownfield-codingWrote 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.
[](https://agentmods.dev/commands/ralfstrobel/agentic-brownfield-coding/build)<a href="https://agentmods.dev/commands/ralfstrobel/agentic-brownfield-coding/build"><img src="https://agentmods.dev/badge/commands/ralfstrobel/agentic-brownfield-coding/build/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/commands/ralfstrobel/agentic-brownfield-coding/build"><img src="https://agentmods.dev/badge/commands/ralfstrobel/agentic-brownfield-coding/build.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 5.1 | $0.00017 | $0.01246 |
| Opus 5.5 | $0.00007 | $0.00498 |
| Sonnet 5.5 | $0.00003 | $0.00249 |
| Haiku 4.5 | $0.00002 | $0.00125 |
Grade A, and why
build 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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 113 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Cooperative Development Request
The user wants to make the following complex additions / changes to the codebase: $ARGUMENTS
Adhere strictly to the following development workflow protocol.
Phase 1: Define
- Establish which repo components or sub-projects are target of the development (from user request or user role).
- Invoke any skills relevant to the development scope.
- Confirm the user's intent: the problem being solved, success criteria, what is out of scope, design constraints. Ask the user only about points the request and context leave genuinely unclear.
Phase 2: Research
- Use the project's specialized exploration subagents to locate all code parts relevant to the development request. Launch multiple exploration agents in parallel when the request spans different components or sub-projects.
- Pay special attention to system reminders that disclose additional context or skills upon reading files as such path-specific context is typically highly relevant. Invoke skills or read referenced files as suggested.
Phase 3: Challenge
Scrutinize the request based on the research findings. Probe at minimum:
- Failure modes and edge cases.
- Hidden complexity the request glosses over.
- Security and invariants the existing architecture depends on.
Surface the resulting risks, assumptions, and open questions to the user, and resolve blocking ambiguities before moving on.
Phase 4: Strategize
Formulate between two and four different implementation approaches (one sentence summaries).
Think hard about this and intentionally vary approaches along dimensions that matter most in complex codebases:
- Scope: How much existing code is modified vs. extended or wrapped around?
- Conformity: Does the approach adopt existing structures, or does it introduce new concepts/abstractions?
- Changeability: How easy will it be to modify the resulting code for new requirements?
Present the final approach options to the user to choose from or discuss.
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.
- 1mo ago First seen · 113 lines · 17 tokens per session scan A ead0306aff17
build is a command published in the GitHub repository ralfstrobel/agentic-brownfield-coding (32 stars, last pushed 2d ago), licensed Apache-2.0. It adds 17 tokens to every session and 1,246 once invoked, about $0.0001 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 2026-08-30.
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