Kakunin MCP vs Vulnify
A side-by-side look at the Kakunin MCP and Vulnify MCP servers: transport, auth, tools, quality signals, and the config to install either one in Claude, Cursor, Windsurf or VS Code.
Verdict: choose Kakunin MCP for security work as a local process; choose Vulnify for security as a local process. You can also run both side by side in one mcpServers block.
Which MCP server should you choose?
Choose Kakunin MCP when
- You need dedicated capabilities in the Security domain.
- You prefer a local stdio subprocess transport.
- Its auth model fits you: API key required.
- You have the keys it needs:
KAKUNIN_API_KEY, KAKUNIN_AGENT_ID. - You want tools like
verify_agent_scope, check_risk_score, audit_log_append.
Choose Vulnify when
- You need dedicated capabilities in the Security domain.
- You prefer a local stdio subprocess transport.
- You have the keys it needs:
VULNIFY_API_KEY. - You want tools like
check_action, decide_action, get_decision.
Feature & specification comparison
Rows where the two servers differ are marked.
| Spec | ||
|---|---|---|
| Category | Security | Security |
| Quality signal | 59/100 · Good | 63/100 · Good |
| Install command | Confirmed | Confirmed |
| Transport | Local subprocess (stdio) | Local subprocess (stdio) |
| Auth | API key required | Not declared |
| Pricing | Freemium | Not declared |
| Required env vars | KAKUNIN_API_KEYKAKUNIN_AGENT_ID | VULNIFY_API_KEY |
| Verified owner | Community listing | Community listing |
| GitHub stars | 1 | 2 |
| Directory activity | 5 views 0 installs 0 upvotes | 1 views 0 installs 0 upvotes |
| Tools | 3 | 7 |
| Full listing | View Kakunin MCP | View Vulnify |
Tools & capabilities
Kakunin MCP tools 3
verify_agent_scopeCheck whether this agent is authorised to perform an action before executing it. Verifies the active X.509 certificate, permitted_actions scope, financial limits, and revocation status.check_risk_scoreRetrieve the agent's rolling 30-day risk score, band (`low`/`medium`/`high`), drift trend, and actionable guidance. No input required.audit_log_appendAppend a behavioral event to the agent's immutable audit log. Returns risk score + transaction ID. Events scoring ≥ 0.85 auto-trigger a certificate revocation check.
Vulnify tools 7
check_actionUse for what-if questions when you are not about to act. Dry-run a proposed action against the organization policies (POST /v1/policies/test, one case, stored policies). This skips the PII scan and records nothing: no security event and no audit entry. There is no content field and no DLP scan. The result has no event id and no finalDecision. decide_action is the call that records a decision. Dry runs are limited to 60 requests per minute per key. test_policies covers up to 200 cases in one call.decide_actionCall this before a consequential action with any tool or connector: sending an email or message, exporting or sharing data, deleting data, writing to production or financial records, payments, or external API writes. ALLOW: proceed. REVIEW: hold the action, tell the user it waits for approval in Vulnify, and check again with get_decision. BLOCK: skip the action and explain the reasons. Records a decision for a proposed action (POST /v1/events). This writes a security event and an audit entry, counts toward the organization quota, and may open a human review. The finalDecision field is the authoritative result. decision is what was stored and does not change when a review is resolved. finalDecision stays REVIEW until a human approves, denies, or the review expires. This tool does not approve the review. A REVIEW or BLOCK finalDecision means the action was not allowed. Optional content is scanned in memory and is not stored. An idempotencyKey makes a retry return the same event.get_decisionRead a recorded decision (GET /v1/events/{id}), including a REVIEW. finalDecision is REVIEW while the review is pending, then ALLOW after approval or BLOCK after denial or expiry. decision itself does not change. The finalDecision field is the authoritative result. waitMs polls until finalDecision is ALLOW or BLOCK, or until the bounded wait elapses (30 seconds maximum). waitTimedOut is true when the wait ended and finalDecision is still REVIEW. This does not approve or deny the review.list_policiesList the organization policies as code (GET /v1/policies). Returns apiVersion vulnify.io/v1 and policies sorted by name. Read-only. Any non-revoked API key of the organization may call it. Limited to 60 requests per minute per key.test_policiesEvaluate up to 200 policy cases without recording an event (POST /v1/policies/test). When policies is omitted, the enabled stored policies are used. When policies is set, those proposed policies are evaluated instead and nothing is written. This skips the PII scan: cases have no content field. pass is null when a case omits expect. One call covers up to 200 cases. Limited to 60 requests per minute per key.plan_policy_changesDiff policy creates, updates, and deletes without writing them (POST /v1/policies/apply). dryRun is forced to true and cannot be turned off. Nothing is stored and no audit entry is written. prune only marks missing policies for deletion in the plan. Requires an org-wide LIVE API key; a TEST key or an agent-bound key is refused with 403. This tool does not apply the plan.check_mcp_tool_callRecords a decision for a downstream MCP tool call (POST /v1/gateway/mcp). Vulnify maps the tool name to an action by substring and returns the same recorded decision as decide_action, including an id. This writes a security event and an audit entry. The tool arguments are not executed. The finalDecision field is the authoritative result. A REVIEW or BLOCK finalDecision means the downstream tool was not allowed. This server cannot approve the review. An idempotencyKey makes a retry return the same event.
Ready-to-paste client configs
Paste either block (or both) into your client config, e.g. claude_desktop_config.json or ~/.cursor/mcp.json. We only show a config when the install command is confirmed.
Kakunin MCP
{
"mcpServers": {
"kakunin-ai-kakunin-mcp": {
"command": "npx",
"args": [
"-y",
"@kakunin/mcp"
],
"env": {
"KAKUNIN_API_KEY": "YOUR_KAKUNIN_API_KEY_HERE",
"KAKUNIN_AGENT_ID": "YOUR_KAKUNIN_AGENT_ID_HERE"
}
}
}
}
Vulnify
{
"mcpServers": {
"vulnify": {
"command": "npx",
"args": [
"-y",
"@vulnify/mcp"
],
"env": {
"VULNIFY_API_KEY": "YOUR_VULNIFY_API_KEY_HERE"
}
}
}
}
Frequently asked questions
Kakunin MCP is categorized under Security and uses a local stdio subprocess. Vulnify belongs to Security and uses a local stdio subprocess. Pick Kakunin MCP for security work and Vulnify for security.
Copy the mcpServers block from the config section on this page into your client's config (for example claude_desktop_config.json or ~/.cursor/mcp.json), then fully restart the client.
Kakunin MCP is listed as freemium — a free tier with paid plans. Auth: api key required. Vulnify has no declared pricing — check the project's own site. If a server needs environment variables such as API keys, define them under the env key in your client's MCP config.
Yes. MCP clients support multiple servers: add kakunin-ai-kakunin-mcp and vulnify as separate keys in the same mcpServers object, and your assistant will call tools from either one.
On AllMCPs, Kakunin MCP has a quality signal of 59/100 (Good) with 5 views, 0 installs and 1 GitHub stars. Vulnify has 63/100 (Good) with 1 views, 0 installs and 2 GitHub stars.