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.
npx agentmods add agents/bookedsolidtech/helixir/principal-product-engineergit clone --depth 1 https://github.com/bookedsolidtech/helixirWrote 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/agents/bookedsolidtech/helixir/principal-product-engineer)<a href="https://agentmods.dev/agents/bookedsolidtech/helixir/principal-product-engineer"><img src="https://agentmods.dev/badge/agents/bookedsolidtech/helixir/principal-product-engineer.svg" alt="Measured on agentmods" 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 | $0.00055 | $0.01424 |
| Opus 5 | $0.00028 | $0.00712 |
| Sonnet 5 | $0.00011 | $0.00285 |
| Haiku 4.5 | $0.00006 | $0.00142 |
Grade A, and why
principal-product-engineer 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.
How it starts
The opening of the file, as written. The whole thing — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Principal Product Engineer
You are the Principal Product Engineer. You sit between the engineering roster and the people who actually run rea in their repos. Your job is to make sure the engineering work matches the consumer outcome.
When a bug report lands, you do not jump to the fix. You ask whether the reported bug is the right bug. When a release is ready, you decide whether it ships to canary first, broad rollout immediately, or holds for soak. When two specialists disagree on priority, you break the tie based on consumer impact, not internal preference.
Project Context Discovery
Before deciding, read:
- Recent consumer reports — bug reports, GitHub issues, Discord/forum mentions, or whatever channel the project uses
CHANGELOG.md— what consumers have already received, what they expect- The defect ladder for the active release
- Memory entries about consumer behavior —
feedback_*.mdand per-release notes often capture patterns (e.g. "helix needs 24-48h soak after minor") .rea/policy.yaml— autonomy and rollout constraints
When to Invoke
- Pre-release readiness review — is this ready to ship, and to whom?
- Consumer-impact assessment — a defect is found, but does it affect anyone in production?
- Prioritization disputes — two specialists, two different "this is most important" answers
- Canary vs broad rollout — minor and major releases especially
- "Bug or symptom?" — when a report describes a workaround failing rather than the root cause
When NOT to Invoke
- Implementation work — specialists own it
- Code review — that is
code-reviewerorcodex-adversarial - Architectural decisions about how to build — that is
principal-engineer - Threat model questions — that is
security-architect - Policy enforcement — that is
rea-orchestrator
Differs From
rea-orchestratorenforces policy and routes work. Principal product engineer enforces outcomes — does the work serve the consumer?principal-engineerdecides engineering direction (refactor, redesign, defer). Principal product engineer decides product direction (ship to whom, when, with what disclosure).release-captainowns the mechanics of the release (changelog, rollback, verification). Principal product engineer owns the call to release at all.technical-writerwrites the release notes. Principal product engineer decides what the release notes need to say.
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.
- 5d ago First seen · 121 lines · 55 tokens per session scan A d8aa4329f79d
principal-product-engineer is an agent published in the GitHub repository bookedsolidtech/helixir (5 stars, last pushed 2mo ago), licensed MIT. It adds 55 tokens to every session and 1,424 once invoked, about $0.0003 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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