Dvalincode

English · 中文 · 🌐 dvalincode.dev

Open security engineering for code written by humans and AI agents.
Every repair carries its own proof.

When an agent fixes a security finding, someone has to decide whether the fix worked. Almost every tool asks the model that wrote it — which is the one question a model cannot answer against its own interest.

Dvalin decides instead, and hands you the proof. It re-scans, runs your project's own tests itself, and reads the exit codes from processes it started. Who wrote the repair — our agent, Claude Code, Codex, Copilot, a person — is recorded and never consulted. The result is a Verified Fix Record: a small JSON file anyone can re-check offline, on a laptop with no network and no Dvalin state.

dvalin verify-fix fix-record.json

Fix record 2c9d71ac03e0 · VERIFIED · scan-and-checks
  executor: claude-code (recorded, not consulted)
  targets: 1 before · 0 remaining
  coverage: complete → complete
  introduced: 0 (gate high/new)
  outcome: verified
  ✓ test: npm run test (exit 0)
  audit: run verify-36509f42 @ 414644c75af0

That record says something narrow on purpose: these findings were gone, and these checks were observed to pass. It is not a claim that your code is safe, and Dvalin will not let it be read as one — every record carries what the scan actually covered, and a repair no check could confirm does not pass. The open profile →

A repair is a change, and a change can add as well as remove. So the record also carries what the re-scan saw that the first scan did not, and the gate threshold the verdict was reached under: a fix that removes an eval and introduces an SQL injection is recorded as regressed and does not verify. Neither does a record whose issuer never looked — introduced: not determined fails, because a verifier that skips the question must not score better than one that asks it and finds something.

Dvalin is the independent security runtime between code generation and merge. Humans, coding agents, and CI call the same versioned contract for discovery, remediation, and verification. It runs independently, or interoperates with specialist systems such as Codex Security through portable SARIF. Its built-in coding capability is a remediation executor — not the trust boundary, and not an attempt to compete with every general-purpose coding agent. See the security-agent strategy.

⏱️ 30 seconds, no install, no API key

npx dvalincode security scan .
# After installing the package: dvalin scan .

That is the whole thing. It runs the built-in rules for injection, hardcoded secrets, XSS, eval, and unsafe shell use against the current directory and prints what it found. No account, no model, no config, no code leaves your machine. The default policy runs only Dvalin Built-in, so the first scan always works. Add optional engines explicitly, or inspect their fixed install commands:

dvalin scanners list
dvalin scanners install semgrep       # review the command
dvalin scanners install semgrep --yes # execute it under Dvalin policy

For an incremental “no new high-risk findings” gate, commit the policy and baseline with the repository:

dvalin init
dvalin baseline
dvalin scan

This creates dvalin.security.json and .dvalin/baseline.json. Suppressions require a reason and may have an owner and expiry date. Scan output is a versioned envelope with a deterministic gate result and a resumable workflow ID.

Or put it on every pull request — nothing to install at all

# .github/workflows/security.yml
permissions:
  contents: read
  security-events: write
steps:
  - uses: actions/checkout@v5
    with:
      fetch-depth: 0        # so the scan can reach the base commit
  - uses: arthurpanhku/dvalincode@v0.18.0
    with:
      fail-on: high
      diff: true            # only report on what this PR changed

Findings land inline on the pull request diff and in your Security tab. No API key, no secrets, no model — the scan is deterministic and local to the runner. Full example →

diff: true reports only on lines the pull request changed, so the gate blocks what this change adds instead of everything the repository already carried. That is what makes the check adoptable on a codebase that was not clean to begin with. Drop it to scan the whole repository.

Every comment states what the scan covered — complete, partial, or unknown — beside the result, because "no findings" from a run where half the engines were missing is not the same answer as "no findings" from a complete one.

And publish the proof next to the diff

If your pipeline produced a fix record, hand it to the same action:

  - uses: arthurpanhku/dvalincode@v0.18.0
    with:
      fix-record: fix-record.json

The runner re-derives the record from the file alone — recomputing its hash and re-deriving its verdict from its own evidence — and posts the result on the pull request. A record that was edited after it was issued fails here, and fails the job. The reviewer does not have to trust the pipeline that produced it, or us.

🔏 Verified Fix Record
✅ ce504a995395 · VERIFIED · scan-and-checks
- repaired by claude-code — recorded, and not consulted for this verdict
- targets: 1 before → 0 remaining
- coverage: complete → complete
- introduced: none (gate high/new)
- outcome: verified
- ✓ test: `npm run test` (exit 0)
- audit chain: verify-eeb1bae7 @ 80881867270d

A repair that regressed says so in the same place, and fails the job with it:

❌ 916e2eeaf065 · NOT VERIFIED · scan-and-checks
- introduced: 1 finding(s) the first scan did not report (gate high/new)
  - critical dvalin/sql-injection — src/db.ts:31
- outcome: regressed

Or let your agent call it

If an agent is writing the code, something other than that agent has to check it. DvalinCode is an MCP server, so any agent that speaks MCP can:

claude mcp add dvalin -- npx -y dvalincode mcp-serve --workspace .

One command configures the editor you actually use:

npx dvalincode mcp-install cursor        # .cursor/mcp.json
npx dvalincode mcp-install vscode        # .vscode/mcp.json
npx dvalincode mcp-install claude-code   # .mcp.json

The formats differ in a way that fails silently — VS Code keys its servers under servers, Cursor under mcpServers — so the command writes the right one and merges into whatever is already there. Editors and MCP →

dvalin_scan accepts diff: "uncommitted", which reports only on what the agent just wrote rather than everything the repository already carried — the difference between a usable answer and a wall of pre-existing findings. It never runs a model, edits the target workspace, or persists Dvalin state, so clients can allow the preview by default. When a finding will be repaired, the agent explicitly calls dvalin_begin_verification to record a small local workflow; it can then retrieve the finding by fingerprint and request an independent re-scan through dvalin_get_finding and dvalin_verify_findings.

That last one is the point: an agent that has just written a repair can ask for an independent verdict on it. Dvalin re-scans, runs the project's own checks itself, and returns a Verified Fix Record — what was targeted, what remains, what the repair introduced that was not there before, the gate the verdict was reached under, which commands ran and the exit codes Dvalin observed, and how much of the codebase was actually covered. Whoever wrote the repair is recorded and never consulted. dvalin_verify_fix re-derives such a record offline, so the reviewer receiving it does not have to trust the tool that issued it. FVP-1 → Responses include MCP structuredContent; scanner readiness is available through dvalin_list_scanners. The same server exposes dvalin_run_task as an optional implementation helper, plus session and audit evidence tools.