assign_member_to_card
Assign a member to a specific card
This record as markdown: /tools/io-github-delorenj-mcp-server-trello/assign-member-to-card.md
What assign_member_to_card does on Trello
AI agents use assign_member_to_card to create or update resources in Trello, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Trello environment.
Why assign_member_to_card is rated Medium
This tool creates or updates a membership relationship on a Trello card. While it changes state (the card's assignee list), the action is fully reversible (members can be unassigned), and it does not delete data, execute external code, move financial value, or trigger irreversible destructive operations. The blast radius is limited to card assignment state within a Trello board.
From the tool's definition Tool description states 'Assign a member to a specific card' — this modifies card metadata by adding a member assignment, which is a reversible write operation typical of Trello's API.
Attacks that exploit this kind of access
The rule that runs assign_member_to_card safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Trello, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For assign_member_to_card, this is the rule to start with:
assign_member_to_card 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Trello, apply this rule, and every assign_member_to_card call is checked against it from then on.
Questions about assign_member_to_card
Assign a member to a specific card. It is categorised as a Write tool in the Trello MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Trello MCP server in PolicyLayer and add a rule for assign_member_to_card: 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 Trello. Nothing to install.
assign_member_to_card 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 assign_member_to_card 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 assign_member_to_card. 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.
assign_member_to_card is provided by the Trello MCP server (@delorenj/mcp-server-trello). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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