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 yogsoth-ai/north-star-crystallization --skill feasibility-checkgit clone --depth 1 https://github.com/yogsoth-ai/north-star-crystallizationWrote 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/yogsoth-ai/north-star-crystallization/feasibility-check)<a href="https://agentmods.dev/skills/yogsoth-ai/north-star-crystallization/feasibility-check"><img src="https://agentmods.dev/badge/skills/yogsoth-ai/north-star-crystallization/feasibility-check/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/yogsoth-ai/north-star-crystallization/feasibility-check"><img src="https://agentmods.dev/badge/skills/yogsoth-ai/north-star-crystallization/feasibility-check.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 | $0.00039 | $0.00189 |
| Opus 5 | $0.00019 | $0.00095 |
| Sonnet 5 | $0.00008 | $0.00038 |
| Haiku 4.5 | $0.00004 | $0.00019 |
Grade A, and why
feasibility-check 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 9d 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.
What it actually says
Feasibility Check
Reality-check the GoalTree against the user's actual situation.
Execution
Subagent — spawned via subagent-spawning/spawn-agent skill.
Input
- GoalTree (full structure)
- ActorProfile
- ObstacleReport
Checks Against
- ActorProfile: Can this user do each leaf?
- ObstacleReport: Are known barriers addressed?
- Timeline: Can it be done in time?
Output
Feasibility assessment per branch — feasible / stretch / infeasible + reasoning. For infeasible paths: suggest OR alternatives.
What ships with it
1 file 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.
- 9d ago First seen · 32 lines · 39 tokens per session scan A d84e08493b82
feasibility-check is a skill published in the GitHub repository yogsoth-ai/north-star-crystallization (2 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 39 tokens to every session and 189 once invoked, about $0.0002 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.
Other skills, from other repositories
journal-abbrev
Uma ferramenta para consultar e padronizar abreviações de nomes de revistas e periódicos científicos, incluindo os formatos ISO 4 e MEDLINE. Também trabalha com nomes de periódicos em arquivos BibTeX, usados para referências bibliográficas.
kami-deck
A lab-meeting deck on gut-microbiome links to sleep quality — the design, the results, the caveats, and the next experiment. Built as a decision-grade academic research deck for lab group, PI.
git-workflow
This skill should be used when the user asks to "create git commit", "manage branches", "follow git workflow", "use Conventional Commits", "handle merge conflicts", or asks about git branching strategies, version control best practices, pull request workflows. Provides comprehensive Git workflow guidance for team…
architecture-design
Use only when creating new registrable ML components that require Factory or Registry patterns.
daily-paper-generator
Use when the user asks to generate daily paper digests on a general topic. This skill supports both arXiv and bioRxiv (or either one), then produces structured Chinese/English summaries for selected papers.
ads-launch
Draft or explicitly apply a paid-ad campaign launch through Claude Ads capability-gated adapters. Use for campaign creation, launch plans, publishing ads, activating campaigns, uploading creative, or requests to push a campaign live.