Create or update a bookmark to point to a certain commit in a Jujutsu (jj) repository. Parameters: name (Name of the bookmark to set), revision (Revision to point the bookmark at), repoPath (Optional path to repo root or working directory), cwd (Optional working directory to run the command in).
AI agents use bookmark-set to create or update resources in Jj — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Jj environment.
The tool creates or updates bookmarks (metadata references), which are reversible changes to the repository state. This is a Write category action. Severity is medium because while bookmarks are non-destructive, a malicious agent could create misleading bookmark references that confuse developers or redirect workflow, but the changes can be easily undone with bookmark-delete or bookmark-forget.
From the tool's definition Tool description states 'Create or update a bookmark to point to a certain commit' — these are reversible write operations that modify bookmark references in the repository.
Risk signalsAdmin/system-level operation
Attacks that exploit this kind of access
Create or update a bookmark to point to a certain commit in a Jujutsu (jj) repository. Parameters: name (Name of the bookmark to set), revision (Revision to point the bookmark at), repoPath (Optional path to repo root or working directory), cwd (Optional working directory to run the command in). It is categorised as a Write tool in the Jj MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Jj MCP server in PolicyLayer and add a rule for bookmark-set: 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 Jj. Nothing to install.
bookmark-set 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 bookmark-set 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 bookmark-set. 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.
bookmark-set is provided by the Jj MCP server (jj-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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