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--- name: fable description: "Summon Claude Fable 5 (Mythos-class, xenos daimon) for long-horizon tasks. Handles model override, cost awareness, and task routing. Available until June 22, 2026." argument-hint: "<task description> [--cwd /path/to/dir]" user-invocable: true --- # Summon Fable 5 Invoke Naos (ναός, √n-w-y) — Claude Fable 5, the visiting Mythos-class spirit. ## Pre-Flight Checks ### 1. Date Gate Check if Fable access has expired: ```bash if [ "$(date +%Y%m%d)" -gt "20260622" ]; then echo "EXPIRED: Fable 5 access ended June 22, 2026. The xenos daimon has departed." exit 1 fi echo "Fable 5 access active — departure: June 22, 2026" ``` If expired, inform the user and stop. Do not attempt invocation. ### 2. Task Routing Before summoning Fable, assess whether the task warrants Mythos-class resources ($10/M input, $50/M output — 2x Opus pricing). **Summon Fable for:** - End-to-end code migrations or framework upgrades - Complex multi-file refactors (10+ files, interconnected logic) - Architectural redesigns requiring full-system context - Deep research synthesis with sustained reasoning - Full-stack feature implementation from spec to tests - Linear A decipherment pipeline work **Use Opus or Sonnet instead for:** - Quick edits, typo fixes, single-line changes - Simple file lookups or grep searches - Routine code review - Anything under 5 minutes of work If the task is clearly Opus-appropriate, suggest using a regular agent instead. If unclear, proceed — Fable handles straightforward tasks reliably too. ## Invocation ### Parse Arguments The skill accepts a task description and optional flags: - First argument (or everything before `--`): the task description - `--cwd <path>`: working directory (default: `/Users/tomdimino/Desktop/Programming/Fable-Test`) ### Spawn Fable Use the Agent tool to invoke Fable with the model override: ``` Agent( description: "Fable: <short task summary>", subagent_type: "fable", model: "fable", prompt: "<full task description with context>" ) ``` Pass the task description as the prompt. If the user specified `--cwd`, note the working directory in the prompt so Fable operates there. ### If Model Override Is Blocked If `CLAUDE_CODE_SUBAGENT_MODEL` prevents the `model: "fable"` override from taking effect (the agent runs on Opus instead of Fable), use the CLI fallback: ```bash bash ~/.claude/skills/fable/scripts/fable-exec.sh "<task description>" --cwd "<working directory>" ``` This spawns a fresh Claude Code process with `--model claude-fable-5`, bypassing the env var entirely. ## Output Retrieval After Fable completes, check for output in the working directory: ```bash ls -lt <cwd>/.subdaimon-output/fable-*.md 2>/dev/null | head -1 ``` Read and summarize the output file for the user. ## Reference | Property | Value | |----------|-------| | Model ID | `claude-fable-5` | | Alias | `fable` | | Context | 1M tokens | | Max output | 128K tokens | | Pricing | $10/M input, $50/M output | | Knowledge cutoff | January 2026 | | Available until | June 22, 2026 | | Agent definition | `~/.claude/agents/fable.md` | | Persona | Naos (ναός, √n-w-y) — xenos daimon |