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 skills add elbwalker/walkerOS --skill walkeros-create-transformergit clone --depth 1 https://github.com/elbwalker/walkerOSWrote 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/skills/elbwalker/walkeros/walkeros-create-transformer)<a href="https://agentmods.dev/skills/elbwalker/walkeros/walkeros-create-transformer"><img src="https://agentmods.dev/badge/skills/elbwalker/walkeros/walkeros-create-transformer/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/skills/elbwalker/walkeros/walkeros-create-transformer"><img src="https://agentmods.dev/badge/skills/elbwalker/walkeros/walkeros-create-transformer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00050 | $0.03153 |
| Opus 5.5 | $0.00020 | $0.01261 |
| Sonnet 5.5 | $0.00010 | $0.00631 |
| Haiku 4.5 | $0.00005 | $0.00315 |
Grade A, and why
walkeros-create-transformer 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.
How it starts
The opening of the file, as written. The whole thing — 406 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Create a New Transformer
Prerequisites
Before starting, read these skills:
- understanding-flow - How transformers fit in architecture
- understanding-transformers - Transformer interface
- understanding-events - Event structure
- testing-strategy - How to test
- writing-documentation - Documentation standards (for Phase 7)
Transformer Categories
| Category | Purpose | Example |
|---|---|---|
| Validate | Check event structure/content | JSON Schema, required fields |
| Enrich | Add data to events | Server timestamps, geo data |
| Redact | Remove/mask sensitive data | Strip PII, anonymize IPs |
Process Overview
1. Research → Understand use case (validate/enrich/redact)
2. Examples → Create event before/after examples FIRST
3. Scaffold → Copy template, configure package.json
4. Convention → Add walkerOS.json metadata and buildDev
5. Implement → Build transformer with TDD
6. Test → Verify against example transformations
7. Document → Write README
Supporting Files
This skill includes reference files you can copy:
- examples/ - Example events and configs to adapt for your transformer
- templates/validation/ - Complete redact
transformer template
- index.ts - Implementation with context pattern
- types.ts - Type definitions
- schemas.ts - Zod validation schemas
- index.test.ts - Test suite with helpers
What ships with it
8 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- examples/config.ts 411 B runs code
- examples/events.ts 825 B runs code
- examples/index.ts 186 B runs code
- templates/validation/index.test.ts 2.4 KB runs code
- templates/validation/index.ts 1.9 KB runs code
- templates/validation/schemas.ts 167 B runs code
- templates/validation/types.ts 201 B runs code
- TESTING.md 1.7 KB
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.
- yesterday Changed · +14 lines d2c63f0eb2a6
- 21d ago Changed · +6 lines be5a47d4a454
- 1mo ago First seen · 386 lines · 50 tokens per session scan A e32f745626eb
walkeros-create-transformer is a skill published in the GitHub repository elbwalker/walkerOS (347 stars, last pushed yesterday), licensed MIT. It adds 50 tokens to every session and 3,153 once invoked, about $0.0002 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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