opus-advisor-mcp

An MCP server that lets Claude Code consult Opus as a strategic advisor mid-task. Run your session on Sonnet or Haiku, and escalate complex decisions to Opus on demand — using your existing Claude Code subscription.

Inspired by Anthropic's Advisor Strategy.

How it works

┌─────────────────────────────────────────────┐
│  Claude Code (Sonnet)                       │
│                                             │
│  "I need to decide on the DB schema..."     │
│        │                                    │
│        ▼                                    │
│  calls consult_opus MCP tool                │
│        │                                    │
└────────┼────────────────────────────────────┘
         │
         ▼
┌─────────────────────────────────────────────┐
│  opus-advisor MCP server                    │
│                                             │
│  1. Reads prior consultation history        │
│  2. Reads requested files from disk         │
│  3. Pipes prompt to: claude -p --model opus │
│  4. Logs advice to advisor-log.md           │
│  5. Returns advice to Sonnet                │
└─────────────────────────────────────────────┘

No API keys needed. The server shells out to the claude CLI, which uses your existing authentication.

Install

npm install -g opus-advisor-mcp

Or clone and build locally:

git clone https://github.com/Divinci-AI/opus-advisor-mcp.git
cd opus-advisor-mcp
npm install
npm run build

Configure

Add to your project's .mcp.json or ~/.claude/.mcp.json:

{
  "mcpServers": {
    "opus-advisor": {
      "command": "opus-advisor",
      "timeout": 180000
    }
  }
}

If installed locally (not globally):

{
  "mcpServers": {
    "opus-advisor": {
      "command": "node",
      "args": ["/path/to/opus-advisor-mcp/dist/index.js"],
      "timeout": 180000
    }
  }
}

Restart Claude Code after adding the config.

Tools

consult_opus

Consult Opus for strategic advice.

Parameter	Type	Default	Description
question	string	required	The question or problem you need advice on
context	string	optional	Additional context, constraints, or background
files	string[]	optional	File paths (relative to project root) to include as code context
effort	"low" | "medium" | "high"	"medium"	Reasoning effort level for Opus
include_history	boolean	true	Include prior consultation history for continuity

Example:

{
  "question": "Is this database migration safe under concurrent writes?",
  "files": ["src/db/migration-042.ts", "src/db/schema.ts"],
  "effort": "high"
}

read_advisor_log

Read the consultation log from prior calls.

Parameter	Type	Description
last_n	number	Number of recent consultations to return (omit for all)

read_advisor_meta

Read structured metadata (latency, token counts, effort levels).

Parameter	Type	Description
last_n	number	Number of recent entries to return (omit for all)

clear_advisor_log

Clear the consultation log and metadata to start fresh.

Features

• No API key required — Uses your existing Claude Code subscription via the claude CLI
• Per-project logs — Consultation history is stored per project at ~/.opus-advisor/<project>-<hash>/
• Code-aware context — Pass file paths directly; the server reads and injects them as labeled code blocks
• Consultation continuity — Prior advice is fed back as context so Opus can build on earlier decisions
• Token-aware history — History is capped by both entry count (5) and token budget (~6K tokens)
• Metadata tracking — Latency, token estimates, and effort levels tracked in advisor-meta.jsonl
• Signal protection — Partial output from killed processes is discarded, not returned as advice
• Path traversal guard — File reads are validated to stay within the project root

Security

• Path traversal protection: The files parameter validates that all resolved paths remain within the project root directory. Paths like ../../etc/passwd or absolute paths outside the project are rejected.
• Binary file filtering: Common binary extensions (images, executables, archives, etc.) are automatically skipped.
• No shell execution: The server uses spawn with array arguments and pipes the prompt via stdin. No shell interpolation occurs.
• Local only: The MCP server runs locally via stdio. No network ports are opened.
• Consultation logs: Stored at ~/.opus-advisor/ in plaintext. These may contain code snippets and questions from your consultations. Do not commit or share these files if they contain sensitive code.

Environment Variables

Variable	Description
ADVISOR_LOG_DIR	Override the log directory (default: ~/.opus-advisor/<project>-<hash>/)

How it compares to Anthropic's Advisor Tool

Anthropic's advisor_20260301 is a server-side API feature where the advisor sees the full conversation transcript within a single API request. This MCP server is a different approach:

	Anthropic Advisor Tool	opus-advisor-mcp
Context sharing	Full transcript (server-side)	Question + files + history (client-side)
Auth	API key required	Uses existing Claude Code subscription
Integration	API-level (tools array)	MCP tool (works in Claude Code today)
Persistence	None	Markdown log + JSONL metadata
Cost	Billed per-token at Opus rates	Included in subscription

Requirements

• Node.js >= 18
• Claude Code CLI installed and authenticated

License

MIT