// MCP TOOL REFERENCE

ctx_upgrade

ServerContext Mode
CategoryExecute

WHAT IT DOES

What ctx_upgrade does on Context Mode

AI agents invoke ctx_upgrade to trigger actions in Context Mode. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

THE RISK

High Risk

Why ctx_upgrade needs a policy

This tool generates and instructs execution of shell commands, which is a hallmark of the Execute category. While framed as an upgrade utility, it runs arbitrary shell operations whose effects are determined by the upgrade script. The severity is high because a malicious or corrupted upgrade command could compromise the system, install malware, or alter configurations.

From the tool's definition The tool 'Returns a shell command to execute' and 'You MUST run the returned command using your shell tool' - this directly triggers external shell command execution whose effects depend on the returned command arguments.

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

POLICY

How to control ctx_upgrade

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

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "ctx_upgrade": {
      "limits": [
        {
          "counter": "ctx_upgrade_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

ctx_upgrade stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

Create a free account and register Context Mode — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Context Mode tools

Destructive ctx_purge DESTRUCTIVE: permanently delete indexed content. Cannot be undone. Requires confirm:true a Execute ctx_batch_execute Run multiple commands in ONE call. Every command Execute ctx_execute Run code in a sandboxed subprocess.${RB} Languages: ${PB}. Think-in-Code \u2014 the core Execute ctx_execute_file Read a file into a sandboxed FILE_CONTENT variable and run code over it. Only what you con Execute ctx_insight Opens the context-mode Insight dashboard in the browser \u2014 a dashboard launcher for se Write ctx_index Store content in a searchable knowledge base (BM25 over FTS5). Splits markdown by headings Write ctx_fetch_and_index Fetches URL content, converts HTML to markdown (JSON is chunked by key paths, plain text i Read ctx_doctor Diagnose context-mode installation. Runs all checks server-side and returns a plain-text s

All 11 Context Mode tools →

Execute tools on other servers

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Go deeper

High-risk tools in Context Mode → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about ctx_upgrade

What does the ctx_upgrade tool do? +

Upgrade context-mode to the latest version. Returns a shell command to execute. You MUST run the returned command using your shell tool (Bash, shell_execute, run_in_terminal, etc.) and display the output as a checklist. Tell the user to restart their session after upgrade. It is categorised as a Execute tool in the Context Mode MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on ctx_upgrade? +

Register the Context Mode MCP server in PolicyLayer and add a rule for ctx_upgrade: 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 Context Mode. Nothing to install.

What risk level is ctx_upgrade? +

ctx_upgrade is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit ctx_upgrade? +

Yes. Add a rate_limit block to the ctx_upgrade 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 ctx_upgrade completely? +

Set action: deny in the PolicyLayer policy for ctx_upgrade. 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 ctx_upgrade? +

ctx_upgrade is provided by the Context Mode MCP server (mksglu/context-mode). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Context Mode tool call.

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

CHECK YOUR STACK →

Free to start. No card required.

11 Context Mode tools catalogued and risk-classified — across an index of 43,000+ MCP servers.