oracle

oracle

A Claude Code plugin marketplace with one plugin: oracle, a fast, cheap way to get a one-shot answer without derailing your main session's context or train of thought.

Before you install

• Requires the claude CLI binary on PATH — the skill shells out to a fresh headless claude -p session. If you're running Claude Code at all, you already have this.
• Uses the fable model. Your account needs access to it.
• Billing: if ANTHROPIC_API_KEY is set in your environment, the skill runs headless with --bare (API rates, off your Claude Code quota). Otherwise it runs --safe-mode (OAuth, counts against your normal plan quota) — no extra cost beyond a small, cheap request.
• The skill has no file access in its headless session — only WebSearch. If a question needs a file's contents, the calling session reads the file first and pastes the relevant lines in.

Installation

Inside a Claude Code session:

Add the marketplace

/plugin marketplace add benjaminjackson/oracle

Install oracle

/plugin install oracle@oracle

(The repo lives at benjaminjackson/oracle; oracle is the marketplace's internal name, used only in the plugin@marketplace install id above.)

Confirm it's installed: run /plugin (Installed tab) or /plugin list.

oracle

One skill, one agent, same job — answer a question as concisely as possible — at two different price points.

oracle (skill)

The default path. Writes your question to a scratch file, then shells out to a bare headless Fable session (claude -p --safe-mode or --bare, whichever fits your setup) with a stripped system prompt. No agent scaffolding, no tool loadout beyond WebSearch — about 1.3k tokens of overhead per question.

Usage

• Explicitly: /oracle <question>
• Automatically: on phrases like "ask the oracle" or "oracle, ..."

Why the scratch-file step

macOS ships bash 3.2 by default, and a heredoc nested inside $(...) breaks the instant the body has a contraction (don't, it's) — a real parser bug, not a wording issue. The skill sidesteps it entirely: write the question to a plain text file with the Write tool (no shell parsing, so quotes and backticks are inert), then read it back with a bare $(cat file).

oracle (agent)

Fallback only, for when the headless call can't run — no claude CLI on PATH, auth broken, sandboxed environment with no shell access. Same brief (shortest correct answer, lead with the word that matters), run as a proper subagent instead of a headless process: Read, Grep, Glob, WebSearch, WebFetch, ~6k tokens per question.

The skill falls back to this agent automatically if the headless command fails, and says so when it does.

Repo structure

.claude-plugin/marketplace.json   # marketplace manifest (this repo)
oracle/.claude-plugin/plugin.json # oracle plugin manifest
oracle/agents/oracle.md           # fallback agent
oracle/skills/oracle/SKILL.md     # headless-Fable skill

Author

Benjamin Jackson (@benjaminjackson)