Medium Risk

via_log

Log a decision, event, or activity to the Via log.

How to control via_log ↓

What via_log does on Via

AI agents use via_log to create or update resources in Via — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Via environment.

Medium Risk

Why via_log needs a policy

This tool writes/appends data to a log. It is reversible in the sense that log entries are additive records, not destructive operations. Misuse could result in log pollution or obfuscation but the blast radius is low.

From the tool's definition 'Log a decision, event, or activity to the Via log' — creates a new log entry

Documented attack patterns abuse exactly the kind of access via_log gives an agent:

How to control via_log

PolicyLayer is an MCP gateway — it sits between your AI agents and Via, and nothing reaches the server without passing your rules. This is the rule we recommend for via_log:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "via_log": {
      "limits": [
        {
          "counter": "via_log_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

via_log stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

  1. Create a free account and register Via — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
LIMIT THIS TOOL →

Free to start. No card required.

Related tools and policies

Go deeper

Questions about via_log

What does the via_log tool do? +

Log a decision, event, or activity to the Via log. It is categorised as a Write tool in the Via MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on via_log? +

Register the Via MCP server in PolicyLayer and add a rule for via_log: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Via. Nothing to install.

What risk level is via_log? +

via_log is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit via_log? +

Yes. Add a rate_limit block to the via_log rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block via_log completely? +

Set action: deny in the PolicyLayer policy for via_log. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides via_log? +

via_log is provided by the Via MCP server (vektor-memory/via). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Via tool call.

Start from Via, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

Free to start. No card required.

8 Via tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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