efficient-fable — Claude Code skill: what it does, how to install
Distributes work between Claude Fable and cheaper subagents. It saves tokens during large repo searches, test runs, and bounded code edits.
npx skills add BuilderIO/skills --skill efficient-fable -a claude-codeWhat efficient-fable does
This skill assigns Claude Fable the role of architect, synthesizer, and final judge. Token-heavy work goes to cheaper subagents instead. They handle doc scans, narrow bug hunts, test log reduction, and bounded code edits.
Work is handed off via self-contained packets. Each packet defines the exact objective, files in scope, expected evidence format, and explicit stop conditions. If a command fails repeatedly or touches files out of scope, the subagent halts instead of guessing.
Subagent reports are treated as leads, not verified facts. Fable must reopen cited files, check the line numbers, and inspect the final patch directly. Delegating tiny tasks or checks that require nuanced context will only add overhead. The repository includes an Excalidraw diagram at assets/fable-orchestrator.excalidraw to illustrate the orchestration flow.
What it helps with
- reduce token spend when searching across large repositories
- run test sweeps and log reductions in parallel subagents
- formulate isolated tasks with clear boundaries and stop conditions
- verify subagent diffs and line references before merging code
Example prompts for the agent
- Use the efficient-fable pattern to delegate repo exploration to a subagent and review its findings.
- Write a handoff packet for a subagent to reproduce this error and return exact commands with diffs.
How to install efficient-fable
1Skills CLI (Vercel)
npx skills add BuilderIO/skills --skill efficient-fable -a claude-code2Manually: put the files in place
~/.claude/skills/efficient-fable/SKILL.mdCopy the whole skill folder; for one project use .claude/skills/efficient-fable/
1Skills CLI (Vercel)
npx skills add BuilderIO/skills --skill efficient-fable -a codex2Manually: put the files in place
.agents/skills/efficient-fable/SKILL.mdFor all projects use ~/.agents/skills/
1Skills CLI (Vercel)
npx skills add BuilderIO/skills --skill efficient-fable -a cursor2Manually: put the files in place
.cursor/skills/efficient-fable/SKILL.mdCursor also reads .agents/skills/ and .claude/skills/
1GitHub CLI
gh skill install BuilderIO/skills efficient-fable2Manually: put the files in place
.github/skills/efficient-fable/SKILL.md1Skills CLI (Vercel)
npx skills add BuilderIO/skills --skill efficient-fable -a gemini-cli2Platform CLI
gemini skills install https://github.com/BuilderIO/skills --path skills/efficient-fableManually: put the files in place
.devin/skills/efficient-fable/SKILL.mdThe legacy .windsurf/skills/ path still works
Skills CLI (Vercel)
npx skills add BuilderIO/skills --skill efficient-fable -a opencodeClaude.ai
Zip the folder and upload it in Settings → Capabilities → Skills
Step by step, with commands for each platform: How to install skills in Claude Code: five ways
Questions about efficient-fable
How to install efficient-fable in Claude Code?
Run npx skills add BuilderIO/skills --skill efficient-fable -a claude-code in your terminal. The configuration is stored at ~/.claude/skills/efficient-fable/SKILL.md.
What is the main purpose of efficient-fable?
It reserves Claude Fable for architectural decisions, tradeoffs, and final reviews. Cheaper subagents take over token-heavy searches, narrow fixes, and test log reductions.
How does Fable verify subagent output?
Fable treats subagent reports as leads rather than facts. It inspects the cited files, checks line references, and reviews the patch before finalizing the task.
Source text
SKILL.md · MIT
--- name: efficient-fable description: Use when running Claude Fable on codebase-heavy or token-heavy work and the user wants Fable to orchestrate research, coding, and testing while cheaper subagents do bounded heavy lifting. --- # Efficient Fable Use Claude Fable as the orchestrator, architect, synthesizer, and final judge. Use cheaper subagents for token-heavy research, coding, testing, and summarization that do not require Fable's full judgment. ## Where Fable Shines Reserve Fable for: - Decomposing ambiguous work into clean parallel slices. - Architecture, product, and safety tradeoffs. - Reading conflicting subagent reports and deciding what matters. - Integrating partial implementations into one coherent plan. - Final review, risk assessment, and user-facing synthesis. ## Delegation Pattern 1. Name the expensive-token risk: large repo search, long logs, broad docs, or repetitive edits. 2. Split independent work into subagents before reading everything yourself. 3. Use cheaper models for research scans, inventory, search summaries, narrow bug hunts, browser/testing passes, test output reduction, and bounded code edits. 4. Ask subagents for concise evidence: files, line references, commands run, diffs, uncertainties, and stop conditions they hit. 5. Spend Fable tokens on the decision layer: compare results, resolve conflicts, choose the implementation path, and review the final patch. Prefer parallel subagents when the slices do not depend on each other. Keep blocking or highly coupled work local. ## Handoff Packets Write delegated prompts as if the subagent has no useful chat context. Include only the context it needs: - The repo path and exact objective. - The files, packages, or surfaces in scope and anything explicitly out of scope. - The evidence format to return: files, line refs, commands, diffs, failures, screenshots, and uncertainty. - The verification commands or browser flows to run, plus what success should look like when that is knowable. - Stop conditions: if the code does not match the prompt, a command fails after a reasonable retry, or the task needs out-of-scope files, stop and report instead of improvising. ## Vetting Delegated Work Treat subagent reports as leads, not facts. Before using a high-impact finding, opening a PR, or telling the user the work is done, Fable should reopen the important cited files, confirm the relevant line refs or failures, and review the final diff against the task. Let lighter agents gather signal; keep truth-judgment with Fable. ## Common Scenarios Treat these as soft defaults, not rigid rules: - Research: ask lighter agents to scan docs, prior art, APIs, and repo surfaces; Fable decides what evidence changes the plan. - Coding: give cheaper agents bounded edits or candidate patches; Fable owns shared-file coordination, integration, and final review. - Testing: have Fable suggest the validation direction and the scripts or browser checks that matter. Let lighter agents run targeted tests, browser flows, screenshots, and log reduction, then report exact commands, failures, likely causes, and whether failures look flaky, environmental, or real. - Debugging: use cheaper agents to cluster logs, reproduce issues, and try small fixes; Fable decides which diagnosis is most trustworthy. If a task is tiny or the validation itself needs delicate judgment, keep it with Fable. ## Diagram Use `assets/fable-orchestrator.excalidraw` when a visual explanation helps. ## Claims For codebase-heavy work, it is reasonable to describe this as up to 3-5x more cost-efficient and 2-4x faster when independent research, coding, or testing slices can run in parallel. Treat those as workload-dependent estimates, not guarantees. Good launch copy: > Make Claude Fable more efficient by using cheaper subagents for token-heavy > research, coding, and testing, saving Fable for judgment, architecture, > synthesis, and final review.
© BuilderIO · MIT · BuilderIO/skills