Flag

Feature flags: ship it dark, then turn it on for who you pick.

Also for this capability: API · CLI · MCP · SDKs

Feature flags: ship it dark, then turn it on for who you pick.

Base URL	`https://api.hanzo.ai`
Operations	8
Auth	`Authorization: Bearer $HANZO_API_KEY`

Specification

Specification pending — no HIP in hanzoai/hips declares capability: flag yet. What this capability serves is below, from the API document; what it is — the store it owns, how it meters, what it publishes — is written as a HIP under HIP-0139.

Four surfaces

Surface	Reaches this capability as	Coverage
REST	`flag` at its own prefix	8 operations
CLI	`hanzo flag …`	8 of 8
SDK	`FlagApi` in every published client	8 methods
MCP	tool `flag` on `https://api.hanzo.ai/v1/mcp`	8 operations, 2 under the document's own id — ask `describe` for the rest

Quickstart

export HANZO_API_KEY=sk-...   # console.hanzo.ai → API keys

Then the first call — a read that needs nothing but the key. GET /v1/flag/defs, operation get_flag_defs:

CLI

SDK

HTTP

MCP

hanzo flag defs list

.ts

.py

.go

.rs

.java

import { Configuration, FlagApi } from 'hanzoai';

const api = new FlagApi(new Configuration({ accessToken: process.env.HANZO_API_KEY }));
const { data } = await api.getFlagDefs();

from hanzoai.cloud import ApiClient, Configuration
from hanzoai.cloud.api import FlagApi

client = ApiClient(Configuration(access_token=os.environ["HANZO_API_KEY"]))
result = FlagApi(client).get_flag_defs()

cfg := hanzoai.NewConfiguration()
cfg.AddDefaultHeader("Authorization", "Bearer "+os.Getenv("HANZO_API_KEY"))
client := hanzoai.NewAPIClient(cfg)

resp, _, err := client.FlagAPI.GetFlagDefs(context.Background()).Execute()
if err != nil {
	return err
}

use hanzo_client::apis::{configuration::Configuration, flag_api};

let mut cfg = Configuration::new();
cfg.bearer_access_token = std::env::var("HANZO_API_KEY").ok();

let result = flag_api::get_flag_defs(&cfg, Default::default()).await?;

import ai.hanzo.cloud.ApiClient;
import ai.hanzo.cloud.api.FlagApi;

ApiClient client = new ApiClient();
client.setBearerToken(System.getenv("HANZO_API_KEY"));

var result = new FlagApi(client).getFlagDefs();

curl https://api.hanzo.ai/v1/flag/defs \
  -H "Authorization: Bearer $HANZO_API_KEY"

MCP reaches flag through the flag tool, which names its 8 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": "get_flag_activity"
         }
       }
     }'

Answers 200 with object — ok.

Endpoints

Endpoint	What it does
`GET /v1/flag/activity`	Returns the caller's flag change log newest-first: every create, update and delete, with the actor and the time.
`POST /v1/flag/decide`	Runs the caller's flag definitions for one identity and returns the flag verdict: which flags are on (or which variant), their payloads, and whether any definition failed to compute.
`GET /v1/flag/defs/{key}`	Returns one flag definition by key, or 404 when the caller's store has none under that key.
`PUT /v1/flag/defs/{key}`	Creates or replaces the flag definition at the path's key and returns the stored row.
`DELETE /v1/flag/defs/{key}`	Removes one flag definition by key and records the deletion in the change log.
`GET /v1/flag/defs`	Returns every flag definition in the caller's (org, project) store, by key, with its version and who last changed it.
`GET /v1/flag/health`	Reports that the flag engine is serving.
`POST /v1/flag`	Runs the caller's flag definitions for one identity and returns the flag verdict: which flags are on (or which variant), their payloads, and whether any definition failed to compute.

All Hanzo APIs · Interactive reference

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