claude-fable-5-skills

10 battle-ready Agent Skills for Claude Fable 5 — the first skill collection designed around how Claude Fable 5 actually behaves, not how older models needed to be babysat.

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Anthropic's own guidance for Fable 5 notes that skills written for prior models are often too prescriptive for it and can degrade output quality. Old skills micromanage; Fable 5 needs intent, boundaries, and verification hooks instead. Every skill here is written Fable 5-first.

Works with Claude Code, Claude Cowork, Cursor, Copilot, Gemini CLI, and any harness that reads SKILL.md files (agentskills.io-style: YAML frontmatter + Markdown body).

The 10 skills

#	Skill	What it fixes
1	`skill-refactorer`	The meta-skill. Audits your pre-Fable-5 skills/prompts, deletes capability-compensation scaffolding, keeps real guardrails.
2	`act-when-ready`	Over-planning at high effort: re-deriving settled facts, surveying options it won't pursue.
3	`effort-calibrator`	Picking the right `effort` level per workload; Fable 5 at `medium` often beats older models at max.
4	`no-gold-plating`	Diffs bigger than the ask: unrequested refactors, speculative abstractions, impossible-state error handling.
5	`grounded-progress`	Status reports on long runs must point at tool-result evidence — no more "tests passing" that never ran.
6	`scope-guard`	"Diagnose" ≠ "fix". No unrequested actions, no state changes on pattern-matched evidence.
7	`subagent-orchestration`	Parallel delegation, long-lived workers, and fresh-context verifier subagents that out-perform self-critique.
8	`markdown-memory`	A file-based lesson memory Fable 5 exploits unusually well — with the maintenance discipline that keeps it useful.
9	`autonomous-continuation`	Unattended runs that stall on "I'll now run X" or mid-run permission questions. Includes the context-budget composure pattern.
10	`regrounding-summary`	Final reports readable by someone who saw none of the work — no arrow chains, no invented abbreviations.

Install

Claude Code (recommended) — install as a plugin, get updates automatically:

/plugin marketplace add kpab/claude-fable-5-skills
/plugin install fable5-skills@claude-fable-5-skills

Manual — copy any skill folder into your skills directory:

git clone https://github.com/kpab/claude-fable-5-skills
cp -r claude-fable-5-skills/skills/act-when-ready ~/.claude/skills/

Or cherry-pick per project by placing folders under .claude/skills/ in the repo. Other harnesses: point your skill loader at the skills/ directory; each skill is a self-contained folder with one SKILL.md.

How the skills activate

Four skills are task-shaped and trigger automatically when a matching request appears: skill-refactorer, effort-calibrator, subagent-orchestration, markdown-memory.

The other six are standing behavioral rules. A model that is mid-over-planning won't reliably decide to invoke act-when-ready on its own, so don't count on auto-triggering for these. Two reliable paths:

Interactive sessions — invoke explicitly (e.g. /act-when-ready) at the start of the session, or the moment the symptom shows up.
Unattended pipelines and always-on use — copy the skill body into your system prompt or CLAUDE.md; this is how Anthropic's own Fable 5 guide ships these patterns. autonomous-continuation is written for exactly this.

Design principles

Intent over procedure. Fable 5 follows instructions strictly; we state outcomes and boundaries, not step-by-step recipes.
Short by construction. Every skill fits on one screen. If a line doesn't change behavior, it's deleted.
Verification hooks, not vibes. Where correctness matters, the skill defines a check (evidence rule, turn-ending check, diff self-check), not an exhortation to "be careful".
Original text. Patterns are informed by Anthropic's public Prompting Claude Fable 5 guide and our own testing; all instruction text here is written from scratch.

Status & disclaimer

Fable 5 shipped on 2026-06-09. These skills track a moving target — expect refinements as the community learns the model. Issues and PRs with reproducible before/after examples are very welcome.

This is an unofficial community project, not affiliated with or endorsed by Anthropic. Verify current API parameters against the official docs before production use.

License

MIT — see LICENSE.