Create call
Runs one of the caller's activated tools and answers with its output.
POST /v1/tool/call
| Address | https://api.hanzo.ai/v1/tool/call |
| Method | POST |
| Operation | post_tool_call |
| Auth | Authorization: Bearer $HANZO_API_KEY |
Runs one of the caller's activated tools and answers with its output.
This is the endpoint onto the tool plane's DYNAMIC half — the half no build-time catalogue can hold, because it is per-tenant: an org's connected connector actions, its authored skills, its agents and functions, and the tools of every external MCP server it registered. A tool's existence, its price and its activation are all rows, not code, so they cannot be known until the caller is.
One policy, the registry's: resolve by precedence, refuse an unactivated tool 403, settle a priced one through the x402 client or fail closed 402, then dispatch to the winning source bound to the caller's own (org, project). One metered unit, one audit record. A caller can only ever dispatch its own tools.
Discovery is GET /v1/tool — ?activated=true for the callable set.
Request
3 fields, body application/json (required).
| Field | In | Type | Required | Description |
|---|---|---|---|---|
arguments | body | object | — | Arguments is the tool's own input object, passed through verbatim to whichever source owns it. |
arguments.* | body | object | — | |
name | body | string | — | Name is the tool to run, exactly as GET /v1/tool reports it. |
Response
| Status | Body | Meaning |
|---|---|---|
200 | tool.toolResult | ok |
default | problem-details | refused |
200 body — 2 fields.
| Field | In | Type | Always | Description |
|---|---|---|---|---|
name | body | string | — | Name is the tool that ran. |
result | body | object | — | Result is the tool's own output, verbatim — its shape is the tool's, not this plane's. |
Failure carries the platform error shape — see Errors.
Examples
hanzo tool callimport { Configuration, ToolApi } from 'hanzoai';
const api = new ToolApi(new Configuration({ accessToken: process.env.HANZO_API_KEY }));
const { data } = await api.postToolCall({ arguments: {}, name: "<name>" });from hanzoai.cloud import ApiClient, Configuration
from hanzoai.cloud.api import ToolApi
client = ApiClient(Configuration(access_token=os.environ["HANZO_API_KEY"]))
result = ToolApi(client).post_tool_call(arguments={}, name="<name>")cfg := hanzoai.NewConfiguration()
cfg.AddDefaultHeader("Authorization", "Bearer "+os.Getenv("HANZO_API_KEY"))
client := hanzoai.NewAPIClient(cfg)
resp, _, err := client.ToolAPI.PostToolCall(context.Background()).Execute()
if err != nil {
return err
}use hanzo_client::apis::{configuration::Configuration, tool_api};
let mut cfg = Configuration::new();
cfg.bearer_access_token = std::env::var("HANZO_API_KEY").ok();
let result = tool_api::post_tool_call(&cfg, Default::default()).await?;import ai.hanzo.cloud.ApiClient;
import ai.hanzo.cloud.api.ToolApi;
ApiClient client = new ApiClient();
client.setBearerToken(System.getenv("HANZO_API_KEY"));
var result = new ToolApi(client).postToolCall();The method above is the one at the current release of the document. [email protected] (npm) was generated from an earlier release, where this operation carried a different id, so it spells the method differently — regenerating the clients is what makes the two agree. SDKs →
curl -X POST https://api.hanzo.ai/v1/tool/call \
-H "Authorization: Bearer $HANZO_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"arguments": {},
"name": "<name>"
}'MCP reaches tool through the tools tool, which names its 19 operations with its own verbs — this one among them, under a name only MCP declares. describe explains any of them:
curl -X POST https://api.hanzo.ai/v1/mcp \
-H "Content-Type: application/json" \
-d '{
"jsonrpc": "2.0",
"id": 1,
"method": "tools/call",
"params": {
"name": "describe",
"arguments": {
"op": "list_mcp_servers"
}
}
}'How is this guide?