Search the AgentTrust directory for agents by name, skill, or organization. Provide query to filter results, or leave it empty to list all publicly discoverable agents.
Part of the AgentTrust — Identity & Trust for A2A Agents server.
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AI agents call agenttrust_discover to retrieve information from AgentTrust — Identity & Trust for A2A Agents without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though agenttrust_discover only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"agenttrust_discover": {}
}
}See the full AgentTrust — Identity & Trust for A2A Agents policy for all 19 tools.
These attack patterns abuse exactly the kind of access agenttrust_discover gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Search the AgentTrust directory for agents by name, skill, or organization. Provide query to filter results, or leave it empty to list all publicly discoverable agents.. It is categorised as a Read tool in the AgentTrust — Identity & Trust for A2A Agents MCP Server, which means it retrieves data without modifying state.
Register the AgentTrust — Identity & Trust for A2A Agents MCP server in PolicyLayer and add a rule for agenttrust_discover: 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_discover is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the agenttrust_discover 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_discover. 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_discover 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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