CodeScene comparison for behavior checks alongside code health

Catch the fix an agent removes later.

A saved requirement makes a recurring mistake checkable. In this Perch capture from September 20, 2026, the same rule flags a missing guard and passes after the guard is restored.

def refund(order, payment):
    payment.refund(order.total)
    order.status = "refunded"
    return order

def refund(order, payment):
    if order.status == "refunded":
        return order
    payment.refund(order.total)
    order.status = "refunded"
    return order

Source: public order-service checkout.py at the linked commit. The captured standalone file is refund.py. Perch command output and timestamp. This saved-rule demonstration does not measure CodeScene's detection rate.

Perch vs CodeScene: what your team runs.

Perch turns project behavior into focused checks that agents can run before committing. Use these differences to choose the review workflow and billing model your team needs.

CodeScene comparison for behavior checks alongside code health

CodeScene measures code health and technical debt. Perch adds a directly runnable English statement of project behavior: the guard, ownership check or write ordering an agent must preserve. Keep that requirement versioned and check the working file before committing.

Review before committing

CodeScene: Local CodeHealth MCP and IDE tools; standalone MCP is €8 or $9/month after trial. CodeScene workflow documentation.

Perch reads the current working file with perch check. For a known requirement, select its rule name and method instead of requesting another broad review. A local CLI describes where the command runs; Perch sends relevant source to hosted TypeSafe models for analysis.

How do saved requirements differ?

CodeScene: Customizable Code Health rules and quality gates. CodeScene rule documentation.

Perch stores English ensure rules in perch.yaml or .perch/rules/. Project, file and method scopes determine what is checked. Run the named check after an edit and after the repair; a rule finding can fail the command and a CI gate. Perch rules · Working-file checks.

What does the review bill depend on?

Compare CodeScene's billing unit and Perch's usage estimate

Is the CLI open source and offline?

CodeScene: Commercial core with separately licensed open components. CodeScene product or license source.

Perch’s CLI is MIT-licensed; hosted model inference is a separate paid service included in its published check rate. It does not run the model offline. Unchanged requests can reuse cached answers for free. Fresh judgments can vary, and a passing requirement check does not prove application correctness. Perch MIT license.

When does CodeScene fit the workflow?

CodeScene analyzes code health, hotspots and knowledge distribution. Its local CodeHealth MCP and broader platform subscription are different products, and neither is an equal-coverage substitute for semantic behavior checks.

Estimate the review bill

Perch and CodeScene: pricing, allowances and workload calculator

Make the agent check its next edit.

npm install -g @lakeday/perch

perch rules add refund-once \
  --where refund.py --each method \
  --ensure "Refunded orders cannot be refunded again."

perch check refund.py::refund --rules refund-once

Use perch scan for repository code at Git HEAD and changed-code CI checks for pull requests. New model judgments can vary. Repeatability comes from cached answers for unchanged requests; a pass does not prove application correctness.