receive_messages
[MAINTENANCE] PARALLEL COORDINATION (d3a3a01d): fetch unread messages addressed to a session (oldest first) and mark them read by default. The receive side of send_message. Persistent-state disclosure: on hosted Meridian, supplied text and project/session metadata -- including task log entries, p...
This record as markdown: /tools/io-github-ajc3xc-meridian/receive-messages.md
What receive_messages does on Meridian
AI agents call receive_messages to permanently remove resources in Meridian, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
| Parameter | Type | Required | Description |
|---|---|---|---|
limit | integer | — | Max messages (default 50). |
mark_read | boolean | — | Mark fetched messages read (default true). |
session_id | string | Yes | The recipient session. |
Parameters from the server's own tool schema.
Why receive_messages is rated Critical
An AI agent that decides to call receive_messages doesn't hesitate, doesn't double-check, and doesn't stop at one. Whatever it removes from Meridian is gone. There is no undo for destructive operations.
Attacks that exploit this kind of access
The rule that runs receive_messages 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 receive_messages, this is the rule to start with:
receive_messages is removed from the agent's tool list entirely, so the agent never calls it. The rest of the server keeps working.
The button opens the PolicyLayer dashboard: create your workspace, connect Meridian, apply this rule, and every receive_messages call is checked against it from then on.
Questions about receive_messages
[MAINTENANCE] PARALLEL COORDINATION (d3a3a01d): fetch unread messages addressed to a session (oldest first) and mark them read by default. The receive side of send_message. Persistent-state disclosure: on hosted Meridian, supplied text and project/session metadata -- including task log entries, pinned decisions, sprint items, notes, handoff/goal state, and HITL queue items -- are sent to and stored in Meridian's service, in an isolated per-tenant Postgres database (Neon); self-hosted deployments keep the same categories in the configured local SQLite/Postgres database. This data is visible in the dashboard and API, and may resurface in later project context or handoffs. Notes and pinned decisions can be deleted individually; task log entries and sprint items can be deleted via the dashboard/API (not exposed as an agent-facing tool); HITL queue items and handoff state have no per-record delete. Full removal of any of this data is available via project or account deletion, using the documented controls. Do not include secrets. It is categorised as a Destructive tool in the Meridian MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
receive_messages accepts 3 parameters: limit, mark_read, session_id. Required: session_id. The full parameter table on this page comes from the server's own tool schema.
Register the Meridian MCP server in PolicyLayer and add a rule for receive_messages: 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.
receive_messages is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the receive_messages 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 receive_messages. 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.
receive_messages 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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