Sets which existing Subject on a wiki page is its Main Subject, or clears it. Enabled only when the wiki has NeoWiki installed. Pass subjectId to promote a Subject that already exists on the page, or null to clear the Main Subject. This differs from neowiki-create-subject with isMain, which creat...
AI agents use neowiki-set-main-subject to create or update resources in MediaWiki MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your MediaWiki MCP Server environment.
This tool modifies page metadata (the Main Subject designation) on a wiki page, which is a reversible change typical of Write operations. It does not create new data (that's neowiki-create-subject), nor does it delete content irreversibly. The requirement for edit rights and its purpose to update existing subjects' status confirms it as a Write operation.
From the tool's definition Tool description explicitly states it "Sets which existing Subject... is its Main Subject, or clears it" and "Requires the edit right." These are characteristic Write operations that modify page metadata reversibly.
Documented attack patterns abuse exactly the kind of access neowiki-set-main-subject gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MediaWiki MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for neowiki-set-main-subject:
{
"version": "1",
"default": "deny",
"tools": {
"neowiki-set-main-subject": {
"limits": [
{
"counter": "neowiki-set-main-subject_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}neowiki-set-main-subject 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.
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Sets which existing Subject on a wiki page is its Main Subject, or clears it. Enabled only when the wiki has NeoWiki installed. Pass subjectId to promote a Subject that already exists on the page, or null to clear the Main Subject. This differs from neowiki-create-subject with isMain, which creates a NEW main Subject. Requires the edit right. Pre-1.0: the NeoWiki API may change without notice. It is categorised as a Write tool in the MediaWiki MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the MediaWiki MCP Server MCP server in PolicyLayer and add a rule for neowiki-set-main-subject: 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 MediaWiki MCP Server. Nothing to install.
neowiki-set-main-subject is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the neowiki-set-main-subject 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.
Set action: deny in the PolicyLayer policy for neowiki-set-main-subject. 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.
neowiki-set-main-subject is provided by the MediaWiki MCP Server MCP server (@professional-wiki/mediawiki-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MediaWiki MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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38 MediaWiki MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.