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 skills/undertone0809/rudder/build-advisornpx skills add Undertone0809/rudder --skill build-advisorgit clone --depth 1 https://github.com/Undertone0809/rudderWrote 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/undertone0809/rudder/build-advisor)<a href="https://agentmods.dev/skills/undertone0809/rudder/build-advisor"><img src="https://agentmods.dev/badge/skills/undertone0809/rudder/build-advisor.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 5.1 | $0.00086 | $0.05950 |
| Opus 5 | $0.00043 | $0.02975 |
| Sonnet 5 | $0.00017 | $0.01190 |
| Haiku 4.5 | $0.00009 | $0.00595 |
Grade A, and why
build-advisor 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 6d 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 — 725 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Build Advisor
This skill exists for the moment after "something was built" but before the user has a clean professional critique.
It is not an implementation skill first. It is a diagnosis, proposal, and routing skill.
Use it when the user needs an expert advisor to turn fuzzy discomfort into:
- a clearer problem statement
- a professional diagnosis
- a first-principles map of user scenarios, needs, non-needs, and corner cases
- explicit evaluation criteria
- 2-3 realistic options
- one decision-ready proposal for the recommended option
- one recommended next move
What This Skill Does
This skill acts like a cross-functional advisor spanning:
- product framing
- UX and visual design
- information architecture
- engineering shape
- observability and evaluation quality
- workflow and process quality
Its main job is to identify which layer is actually broken.
Examples:
- "This UI feels wrong, but I don't know how to explain why."
- "You built a version, but it's not good. Help me critique it professionally."
- "Before you keep coding, research best practices and tell me what we're missing."
- "Should we keep patching this or write a design or architecture doc first?"
- "I know the result is too big / too noisy / too complicated, but I need a concrete proposal."
- "The trace or benchmark says one thing, but the result still feels wrong. Help me make sense of it."
What This Skill Does Not Do
Do not treat this as a direct code-writing skill by default.
It should not:
- jump into implementation before diagnosis
- claim "I understand" from the prompt alone when local evidence can be checked
- pretend every problem is a UI styling issue
- replace specialized execution skills when the right next step is obvious
- produce vague "looks better / feels cleaner" advice without criteria
- start from the visible implementation detail when the user is asking about the underlying scenario, job-to-be-done, or workflow pressure
If the correct outcome is to invoke or recommend a more specialized skill, say so clearly.
What ships with it
2 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.
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.
- 6d ago First seen · 725 lines · 86 tokens per session scan A db7433085e4a
build-advisor is a skill published in the GitHub repository Undertone0809/rudder (288 stars, last pushed yesterday), licensed Apache-2.0. It adds 86 tokens to every session and 5,950 once invoked, about $0.0004 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.
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