Update an existing tiddler. Shows a diff of changes and requests approval before applying. Preserves metadata like created timestamp. Supports arbitrary custom fields beyond the standard ones (e.g., caption, summary, author, or any TiddlyWiki field).
AI agents use update_tiddler to create or update resources in TiddlyWiki MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your TiddlyWiki MCP Server environment.
This tool modifies existing wiki content reversibly. While it preserves metadata (including created timestamps) and requires approval before changes are applied, the core function is to update tiddler data. This is a Write operation—data is changed but can be reverted (unlike Destructive). The approval mechanism reduces but does not eliminate risk, as a human reviewer could be tricked or careless.
From the tool's definition Tool description states 'Update an existing tiddler' and 'Supports arbitrary custom fields beyond the standard ones', indicating reversible modification of wiki data.
Attacks that exploit this kind of access
Update an existing tiddler. Shows a diff of changes and requests approval before applying. Preserves metadata like created timestamp. Supports arbitrary custom fields beyond the standard ones (e.g., caption, summary, author, or any TiddlyWiki field). It is categorised as a Write tool in the TiddlyWiki MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the TiddlyWiki MCP Server MCP server in PolicyLayer and add a rule for update_tiddler: 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 TiddlyWiki MCP Server. Nothing to install.
update_tiddler 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 update_tiddler 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 update_tiddler. 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.
update_tiddler is provided by the TiddlyWiki MCP Server MCP server (ppetru/tiddlywiki-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
update_tiddler is one line of TiddlyWiki MCP Server's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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