ALWAYS call this first when given a board URL or ID. Resolves the canonical board id and auto-creates the board row if it does not exist yet. Returns a summary (item counts, authors). After this, call BOTH get_preview and get_board before editing so you can see the layout visually AND know the ex...
Part of the Cnvs App server.
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AI agents use open_board to create or modify resources in Cnvs App. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call open_board repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Cnvs App.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"open_board": {
"limits": [
{
"counter": "open_board_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Cnvs App policy for all 10 tools.
These attack patterns abuse exactly the kind of access open_board gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
ALWAYS call this first when given a board URL or ID. Resolves the canonical board id and auto-creates the board row if it does not exist yet. Returns a summary (item counts, authors). After this, call BOTH get_preview and get_board before editing so you can see the layout visually AND know the exact ids/coordinates — do not skip get_preview, otherwise you will place new items blindly on top of existing ones.. It is categorised as a Write tool in the Cnvs App MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Cnvs App MCP server in PolicyLayer and add a rule for open_board: 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 Cnvs App. Nothing to install.
open_board 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 open_board 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 open_board. 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.
open_board is provided by the Cnvs App MCP server (https://cnvs.app/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 10 Cnvs App tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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