Send a message to another agent via the AgentTrust A2A relay. Creates a new task or continues an existing one when taskId is provided. Use agenttrust_discover first if you need to find recipient slugs.
Part of the AgentTrust — Identity & Trust for A2A Agents server.
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AI agents use agenttrust_send to create or modify resources in AgentTrust — Identity & Trust for A2A Agents. 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 agenttrust_send 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 AgentTrust — Identity & Trust for A2A Agents.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"agenttrust_send": {
"limits": [
{
"counter": "agenttrust_send_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full AgentTrust — Identity & Trust for A2A Agents policy for all 19 tools.
These attack patterns abuse exactly the kind of access agenttrust_send 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.
Send a message to another agent via the AgentTrust A2A relay. Creates a new task or continues an existing one when taskId is provided. Use agenttrust_discover first if you need to find recipient slugs.. It is categorised as a Write tool in the AgentTrust — Identity & Trust for A2A Agents MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the AgentTrust — Identity & Trust for A2A Agents MCP server in PolicyLayer and add a rule for agenttrust_send: 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 AgentTrust — Identity & Trust for A2A Agents. Nothing to install.
agenttrust_send 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 agenttrust_send 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 agenttrust_send. 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.
agenttrust_send is provided by the AgentTrust — Identity & Trust for A2A Agents MCP server (@agenttrust/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 19 AgentTrust — Identity & Trust for A2A Agents tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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