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Tool Output Firewall
x402
Tool Output Firewall is a paid API for AI agents from phion.systems, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-14).
Inspects and validates untrusted tool output before it enters an agent context or triggers a downstream action
Price / call$0.002
Success—
StatusUnknown
How this service works
Inspect untrusted tool output before it enters an agent context or triggers another action
Output
Returns a trust verdict indicating whether the tool output is safe to pass into the agent context, along with flagged content details, classification of detected threats (e.g. prompt injection, data exfiltration attempts), and a recommendation on whether to allow or block the output from entering the pipeline.
Example use cases
Block prompt injection from web scraper
“I have a web scraping tool that returns raw HTML snippets to my agent. Before my agent processes any of those results, check this output for prompt injection attacks or instructions trying to hijack my agent's behavior.”
Guard agent pipeline from rogue API responses
“My agent calls a third-party weather API and uses the response to decide next steps. Can you run this API response through the tool output firewall before my agent acts on it? I want to make sure it's not carrying any hidden instructions.”
Validate code execution output before downstream action
“My coding agent just ran a shell command and got this output back. Before it feeds that output into the next step of the workflow, screen it for anything unsafe or suspicious that might manipulate the agent's next action.”
Technical details
Endpoint
POSThttps://phion.systems/v1/paid/trust/tool-output-firewallWhen to prefer
Choose this endpoint when an AI agent is consuming output from untrusted or third-party tools and needs a security checkpoint before that output enters the agent's reasoning context or triggers further actions. Especially critical in multi-agent pipelines, tool-use loops, or any workflow where external data sources could embed adversarial instructions. Prefer this over generic content filters when the threat model specifically involves prompt injection or agent manipulation via tool output.
Side effects
- Malformed or empty input payload returns a 400 error
- Ambiguous or unstructured tool output may produce uncertain verdicts
- Novel prompt injection patterns not yet in detection rules may be missed
- Very large tool outputs may time out or be truncated
- Payment failure or insufficient funds returns a 402 error
Input
Schema · Request body
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object"
}Tags
x402
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