A user-friendly adaptive second-opinion skill for Claude Code. For important decisions, plans, strategies, proposals, architecture, and recommendations: frame the real goal, verify decision-critical evidence, pressure-test the biggest risk, compare alternatives, and stop when more reasoning will not change the action.
Crucible is both a Claude Code plugin (.claude-plugin/plugin.json) and a marketplace (.claude-plugin/marketplace.json). No external database, service, or model API key is required for normal plugin use.
Step 1 — Add the marketplace repository:
Step 2 — Install the plugin:
Step 3 — Run Crucible on any decision:
Clone and point Claude Code to the repository root:
| Symptom | Probable Cause | Resolution |
|---|---|---|
| Plugin not found | Marketplace not registered | Run /plugin marketplace add smshahbaj/crucible first |
| Command not found | Claude Code session needs refresh | Restart Claude Code session after installation |
| Ledger script error | Python version below 3.10 | Ensure python3 --version is 3.10 or newer |
“More reasoning is not automatically better. The right amount of reasoning is better.”
Crucible does not turn every request into a large multi-agent debate. It chooses a review depth based on stakes, uncertainty, reversibility, and evidence needs.
Decision → Frame real goal → Route by stakes, uncertainty & reversibility → Targeted specialist lenses → Evidence & verification → Challenge / failure test → Quality control → Stable recommendation.
Having 14 agents echo the same unverified premise is not consensus; it is anchored bias. Crucible enforces independence before collaboration, subjects critical claims to verification gates, and halts when additional reasoning will not change the chosen action.
Crucible conditionally routes across 14 dedicated agent lenses to challenge assumptions without redundant bloat:
claim-compressordecision-routerdecision-strategistevidence-auditorevidence-gateexecution-specialistfailure-analystfinal-judgeoption-analystquality-controllerquantitative-analystrisk-red-teamsource-auditorverification-plannerCrucible's architecture is fully documented across reference modules in skills/crucible/references/:
routing.md)evidence.md)adversarial.md)output-schema.md)quality-gate.md)ledger.md).crucible/ledger.jsonl./plugin marketplace add smshahbaj/crucible in Claude Code, then /plugin install crucible@crucible-marketplace. Alternatively, clone the repository and start Claude Code with claude --plugin-dir ~/crucible for a local install.The optional Decision Ledger lets you record decisions, reasoning, risks, and real-world outcomes locally in durable .crucible/ledger.jsonl format.
Crucible is an adaptive decision-review skill and plugin for Claude Code designed for decisions where reasoning quality matters.
“More reasoning is not automatically better. The right amount of reasoning is better.”
• Project Site: crucible.smshahbaj.com
• Developer: SM Shahbaj (smshahbaj.com)
• Contact: contact@smshahbaj.com
• License: MIT