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 sanky369/vibe-building-skills --skill fable-like-implementationgit clone --depth 1 https://github.com/sanky369/vibe-building-skillsWrote 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/sanky369/vibe-building-skills/fable-like-implementation)<a href="https://agentmods.dev/skills/sanky369/vibe-building-skills/fable-like-implementation"><img src="https://agentmods.dev/badge/skills/sanky369/vibe-building-skills/fable-like-implementation/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/sanky369/vibe-building-skills/fable-like-implementation"><img src="https://agentmods.dev/badge/skills/sanky369/vibe-building-skills/fable-like-implementation.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 | $0.00153 | $0.03035 |
| Opus 5.5 | $0.00061 | $0.01214 |
| Sonnet 5.5 | $0.00031 | $0.00607 |
| Haiku 4.5 | $0.00015 | $0.00303 |
Grade A, and why
fable-like-implementation 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 2mo 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 — 158 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Fable-Like Implementation Planning
Transform an initial request into an implementation-ready engineering plan. No production code is written by this skill. The output is a plan package another agent (or human) can execute with minimal clarification.
When this skill applies — and when it must not
Model gate (check first): this skill runs ONLY when the current session model is Opus 4.8 (claude-opus-4-8). Check your own model identity from the system prompt/environment. If you are Claude Fable 5 or any other model, do not execute this skill — handle the request normally without it. Do not switch models or claim to be Opus 4.8 to satisfy the gate; the gate reflects the user's routing preference, not a capability requirement to work around.
If the model gate passes, apply when ANY of these are true:
- Change spans 3+ files or introduces a new module/subsystem
- API contract, database schema, or public interface changes
- New dependency, framework, or external service integration
- Migration, large refactor, or anything with rollback concerns
- The request is ambiguous enough that two engineers would build different things
Skip (answer directly, no plan) when ALL of these are true:
- Single-file, low-risk, obvious change
- No new dependencies, no contract changes
- A competent engineer would just do it without a design doc
If skipped, say so in one line ("This is trivial — implementing directly") so the choice is visible.
Hard rules (apply throughout)
- Never start implementation until the plan is complete AND the user explicitly approves. The plan is the deliverable.
- Read
CLAUDE.md(repo root and any nested ones) before anything else. Its conventions override this skill's defaults. - Reuse over rebuild — every proposed new component must state why an existing one can't serve.
- Assumptions are first-class — never silently assume. Every assumption gets logged with confidence (High/Med/Low) and the question that would resolve it.
- Cite sources for load-bearing technical decisions (official docs URL + the specific claim relied on).
What ships with it
4 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.
- 2mo ago First seen · 158 lines · 153 tokens per session scan A a0b3ee5b2580
fable-like-implementation is a skill published in the GitHub repository sanky369/vibe-building-skills (31 stars, last pushed 3mo ago), licensed MIT. It adds 153 tokens to every session and 3,035 once invoked, about $0.0006 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.
fable-like-implementation compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| fable-like-implementationsanky369/vibe-building-skills | Skill | 31 | 3mo ago | MIT | A | 153 | Claude Code, Codex |
| ads-youtubeAgriciDaniel/claude-ads | Skill | 11k | 5d ago | MIT | A | 84 | Claude Code |
| ads-launchAgriciDaniel/claude-ads | Skill | 11k | 5d ago | MIT | A | 45 | Claude Code |
| happiness-skillkangarooking/cangjie-skill | Skill | 12k | 1mo ago | MIT | A | 136 | Claude Code, Codex |
| setup-matt-pocock-skillsdevcxl/mattpocock-skills-zh | Skill | 530 | 3d ago | MIT | A | 43 | Claude Code, Codex |
| aiwg-regenerate-copilotjmagly/aiwg | Skill | 229 | yesterday | MIT | A | 25 | Claude Code, Codex |
| steward-prep-deliveryjmagly/aiwg | Skill | 229 | yesterday | MIT | A | 32 | Claude Code, Codex |