arcMCP
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A NATIVE EXTENSION FOR OPENCODE

Less drift.
More direction.

Give your agent a clear arc—from a broad request to focused outcomes, real checks, and two fresh reviewer perspectives.

Find your flow See how it works

Your model. Your tools. A more deliberate finish.

FOCUS FIELDInteractive illustration · move or tap
BUILT WITH RUSTNATIVE TO OPENCODEDESIGNED FOR macOS

MAKE THE WORK COUNT.

Not more agent chatter.
A clearer path to done.

Keep the environment you already use.
Give every outcome something to stand on.

01 / THE ARC OF A TASK

INTENT → EVIDENCE → PERSPECTIVE

Good work has
a through-line.

A compact ledger alongside your native tools. No extra planning model, replacement interface, or reviews after every edit.

ILLUSTRATED WORKFLOW
01—03

Add a CSV export

One request. Connected outcomes.

01PLAN 02CHECK 03REVIEW
EXAMPLE STATE

Scope → headers, encoding, empty rows.

native-advisory / not a live session

Scroll to follow the path. No commands or model calls run in this illustration.

01

LESS SCATTER

A small plan.
A complete scope.

One to five broad, ordered outcomes. Every acceptance detail stays in the plan. Your agent builds with the OpenCode tools and model you chose.

1–5 outcomes · dependency-ordered
02

MORE SIGNAL

Evidence that
stays connected.

Actual commands, captured results, and scoped source fingerprints. A failed, interrupted, unknown, or stale check cannot quietly become a pass.

Real checks · current source
03

A FRESH PERSPECTIVE

Two viewpoints.
One deliberate finish.

Fresh, read-only native reviewers run in parallel. They receive the evidence packet—not the writer’s conversation. Finalize only against current results.

Correctness + adversarial review
And when you stop,
it stops.

New input, questions, and permissions take priority. No automatic restart. No replaying an interrupted check.

02 / GIVE YOUR WORK AN ARC

One command.
A clearer beginning.

Build from versioned source. Keep your existing OpenCode settings. Restart, then start your next request with /arc.

Open sourceMIT licensed · no account required.
INSTALL ARC MCPv0.1.1
curl -fsSL https://pumkin4534.github.io/arc-mcp-site/install.sh | bash

Copy. Run in your terminal. Restart OpenCode.

BRING THESE WITH YOU

  • macOS + Xcode command line tools
  • OpenCode tested on 1.18.25
  • Rust/Cargo + Node.js prepared automatically if needed

03 / KNOW WHAT YOU’RE TRUSTING

NO MAGIC CLAIMS

Strong signals.
Honest boundaries.

Arc is a workflow aid. Its completion records are explicitly native-advisory, not tamper-proof attestations.

Your tools stay native.

Only MCP-owned checks receive scoped macOS Seatbelt restrictions. Other native tools and same-user processes can still modify host records.

Your provider still matters.

No added telemetry service. Local task text, paths and command output are not automatically redacted. Your selected model provider receives the review context.

The scope is explicit.

Fingerprints are non-atomic and exclude ignored/generated/secret content and symlink referents. Process-group cleanup does not cover deliberately detached descendants.