set_active_repo

SERVERMeridian SOURCE@meridianmcp/mcp

Medium RISK CLASS

Category Write

Parameters 20 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-ajc3xc-meridian/set-active-repo.md

WHAT IT DOES

What set_active_repo does on Meridian

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

Parameter	Type	Required	Description
`repo_path`	string	—	Absolute path to the repository to activate (e.g. /home/me/project or C:\\Users\\me\\project). Ignored when worktree_id is given.
`worktree_id`	string	—	32ba4125 — id of a REGISTERED active_worktrees row (from create_worktree) to activate as a validated code-intel context. Takes precedence over repo_path; resolv

Parameters from the server's own tool schema.

RISK

Why set_active_repo is rated Medium

An AI agent can call set_active_repo faster than any human can review: one bad instruction and it creates or modifies resources in Meridian by the hundred, each call as confident as the last.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs set_active_repo safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Meridian, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For set_active_repo, this is the rule to start with:

set_active_repo Rate-limited

set_active_repo 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "set_active_repo": {
      "limits": [
        {
          "counter": "set_active_repo_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Meridian, apply this rule, and every set_active_repo call is checked against it from then on.

FAQ

Questions about set_active_repo

What does the set_active_repo tool do? +

[MAINTENANCE] Update the tunnel's active Serena repo at runtime. When a planning session switches to a different codebase, call this so subsequent Serena requests (find_symbol, find_referencing_symbols, etc.) route to the new repo without restarting the tunnel. Has no effect when no tunnel is connected. 32ba4125 — pass worktree_id instead of repo_path to activate a REGISTERED git worktree (one created via create_worktree / POST /projects/{id}/worktrees) as a validated code-intel context: the repo_path is resolved server-side from that worktree's own record, so an unregistered/arbitrary path can never be activated this way, and the response's worktree field carries fingerprint metadata (worktree_id, project_id, branch, path, registered_at). Passing repo_path directly is unchanged and still works for any path (main-repo/non-worktree use). Persistent-state disclosure: on hosted Meridian, supplied text and project/session metadata are sent to and stored in Meridian's service; self-hosted deployments keep them in the configured local SQLite/Postgres database. This data is visible in the dashboard/API and later project context or handoffs. Delete individual tasks, notes, or decisions where supported, or delete the project/account using the documented controls. Do not include secrets. It is categorised as a Write tool in the Meridian MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

What parameters does set_active_repo accept? +

set_active_repo accepts 2 parameters: repo_path, worktree_id. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on set_active_repo? +

Register the Meridian MCP server in PolicyLayer and add a rule for set_active_repo: 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 Meridian. Nothing to install.

What risk level is set_active_repo? +

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

Can I rate-limit set_active_repo? +

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

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

set_active_repo is provided by the Meridian MCP server (@meridianmcp/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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