post_v1_pubsub_publish

Publish puts one message on the org's bus. When a stream captures the subject the write is DURABLE — the receipt names the stream and sequence only after JetStream has it on storage, and a repeated Nats-Msg-Id header within the dedup window answers duplicate instead of storing twice. When nothing captures it, the message goes out core NATS: delivered to current subscribers, receipt {ok}, nothing retained.


Tool	`post_v1_pubsub_publish`
Door	`https://api.hanzo.ai/v1/mcp`
Method	`tools/call` (JSON-RPC 2.0)
Arguments	3
Operation	`POST /v1/pubsub/publish`
Product	cloud

Arguments

Field	Type	Required	Default	Description
`data`	`string`	—	—	Data is the payload, carried verbatim as UTF-8 text (typically JSON). Binary payloads belong on the NATS port.
`headers`	`object`	—	—	Headers are optional message headers, one value per name. A Nats-Msg-Id header is JetStream's deduplication key: a repeat within the stream's dedup window is acknowledged as duplicate rather than stored twice.
`subject`	`string`	—	—	Subject is the subject to publish to, in the org's own namespace — e.g. orders.created. No wildcards.

This tool's schema does not declare which fields are required, nor any default, nor any enumerated value set. The columns above are empty because the door publishes nothing there, not because the answer is "none" — where a field is constrained, the constraint is stated in that field's own description.

Call it

A tools/call carries every argument in one flat object — nothing binds to a path or a query string. Every declared argument is shown, because the door marks none of them required.

curl -X POST https://api.hanzo.ai/v1/mcp \
  -H "Authorization: Bearer $HANZO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
       "jsonrpc": "2.0",
       "id": 1,
       "method": "tools/call",
       "params": {
         "name": "post_v1_pubsub_publish",
         "arguments": {
           "data": "<data>",
           "headers": {},
           "subject": "<subject>"
         }
       }
     }'

Values are placeholders derived from each field's declared type. tools/list needs no credential; tools/call does — called without one the door answers HTTP 200 with a JSON-RPC result whose isError is set and whose text says what was missing. How to get a key →

The operation behind it

Operation	Route	Product	Summary
`cloud_post_v1_pubsub_publish`	`POST /v1/pubsub/publish`	cloud	Publish puts one message on the org's bus.

The same capability over plain HTTP is in the cloud API reference, on https://api.hanzo.ai.

All 834 tools · The door · API reference

Generated from tools/list on https://api.hanzo.ai/v1/mcp — 834 tools captured 2026-08-01 (this build read the vendored copy; the door was unreachable).

post_v1_pubsub_publish

Arguments

Call it

The operation behind it

On this page