Explainability coverage gate
Ask this BEFORE you analyse why a funnel step loses people. It answers one question — is there enough data here to support a conclusion — and returns no analysis of its own. The response is shaped to be handed to an AI agent verbatim.
It exists because the dangerous case is not a bad number, it is a number that should never have been computed. On a real paid landing page with 4,225 non-bot sessions over 14 days, zero fired the conversion event: the page carries no form, and its step is a click-through to another page. A conversion rate there reads 0.00% and invites "rewrite this page", which is wrong. So outcome_event_never_fires is its own verdict, kept distinct from a genuinely low rate.
Each evidence arm is reported available only when BOTH sides of its contrast hold at least min_arm_n sessions, and every available arm carries a confound field. Treat that field as load-bearing. On that same page the 190 sessions that threw a JavaScript error bounced less than clean ones (80.1% vs 88.1%) and reached the next step three times more often — you have to engage with a page to trigger an error, so the arm measures exposure, not harm. Read causally it claims errors improve conversion.
Counts are page-scoped AND order-scoped. An exception thrown two pages later is evidence about that step, not this one; and "advanced" requires a page after this one, not just a second page somewhere in the session — 17 of 521 sessions on the reference page saw their other page only before it, an error worth 3% on a landing page and approaching 100% mid-funnel. Bots are excluded: unfiltered, that page reads 4,834 sessions instead of 4,225, a 12.6% inflation landing entirely in the denominator.
Finally, available does not mean powered. Each available arm reports mde_pp — the smallest effect it could detect — and the top-level caveat fires when every arm with coverage carries a confound.
curl -X GET "https://mythic-analytics.gulp.workers.dev/client/v1/data/explain/coverage?location_id=example_string&page=%2Fpricing&outcome_event=form_submitted&days=14" \
-H "Content-Type: application/json" \
-H "X-Location-Id: example_string" \
-H "Authorization: Bearer YOUR_API_TOKEN"
import requests
import json
url = "https://mythic-analytics.gulp.workers.dev/client/v1/data/explain/coverage?location_id=example_string&page=%2Fpricing&outcome_event=form_submitted&days=14"
headers = {
"Content-Type": "application/json",
"X-Location-Id": "example_string",
"Authorization": "Bearer YOUR_API_TOKEN"
}
response = requests.get(url, headers=headers)
print(response.json())
const response = await fetch("https://mythic-analytics.gulp.workers.dev/client/v1/data/explain/coverage?location_id=example_string&page=%2Fpricing&outcome_event=form_submitted&days=14", {
method: "GET",
headers: {
"Content-Type": "application/json",
"X-Location-Id": "example_string",
"Authorization": "Bearer YOUR_API_TOKEN"
}
});
const data = await response.json();
console.log(data);
package main
import (
"fmt"
"net/http"
)
func main() {
req, err := http.NewRequest("GET", "https://mythic-analytics.gulp.workers.dev/client/v1/data/explain/coverage?location_id=example_string&page=%2Fpricing&outcome_event=form_submitted&days=14", nil)
if err != nil {
panic(err)
}
req.Header.Set("Content-Type", "application/json")
req.Header.Set("X-Location-Id", "example_string")
req.Header.Set("Authorization", "Bearer YOUR_API_TOKEN")
client := &http.Client{}
resp, err := client.Do(req)
if err != nil {
panic(err)
}
defer resp.Body.Close()
fmt.Println("Response Status:", resp.Status)
}
require 'net/http'
require 'json'
uri = URI('https://mythic-analytics.gulp.workers.dev/client/v1/data/explain/coverage?location_id=example_string&page=%2Fpricing&outcome_event=form_submitted&days=14')
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true
request = Net::HTTP::Get.new(uri)
request['Content-Type'] = 'application/json'
request['X-Location-Id'] = 'example_string'
request['Authorization'] = 'Bearer YOUR_API_TOKEN'
response = http.request(request)
puts response.body
{
"success": true,
"data": {
"page": "example_string",
"window_days": 42,
"answerable": true,
"caveat": "only_confounded_arms_available",
"caveat_note": "example_string",
"reason": "too_few_sessions",
"hint": "example_string",
"outcome": {
"kind": "event",
"note": "example_string",
"event": "example_string",
"n_positive": 42,
"n_total": 42
},
"arms": [
{
"id": "error_outcome",
"available": true,
"n": 42,
"mde_pp": 3.14,
"confound": "exposure",
"confound_note": "example_string",
"reason": "too_few_error_sessions",
"coverage": 3.14,
"form_field_count": 10,
"hint": "example_string"
}
],
"thresholds": {
"min_arm_n": 30,
"min_scroll_coverage": 0.05
}
}
}
{
"error": "Unauthorized",
"message": "Authentication required. Please provide a valid API token",
"code": 401
}
{
"error": "Too Many Requests",
"message": "Rate limit exceeded. Please try again later",
"code": 429,
"retryAfter": 3600
}
/explain/coverage
Target server for requests. Edit to use your own host.
Agency key (ak_) or location secret key (sk_) as a bearer token. Format: Bearer ak_... or Bearer sk_.... Scoped keys (mcp_) are accepted too and need the read scope of the family the route belongs to (people, events, sessions, replays, exceptions, heatmaps or bigquery_export). See Using an mcp_ key over HTTP.
ak_) or location secret key (sk_) as a bearer token. Format: Bearer ak_... or Bearer sk_.... Scoped keys (mcp_) are accepted too and need the read scope of the family the route belongs to (people, events, sessions, replays, exceptions, heatmaps or bigquery_export). See Using an mcp_ key over HTTP.
Alternative to the X-Location-Id header for agency (ak_) keys. Ignored for secret (sk_) keys.
Pathname of the page, for example /pricing. A full URL is accepted and reduced to its pathname.
The event that counts as advancing past this step. Omit it and "advanced" means the session saw a second page — the correct model for a bridge or advertorial page that carries no form.
Lookback window in days.
Location to scope the request to. Required for agency (ak_) keys on the event routes. Ignored for secret (sk_) keys, which resolve their own location, and not used by /export.
Request Preview
Response
Response will appear here after sending the request
Authentication
Bearer token. Agency key (ak_) or location secret key (sk_) as a bearer token. Format: Bearer ak_... or Bearer sk_.... Scoped keys (mcp_) are accepted too and need the read scope of the family the route belongs to (people, events, sessions, replays, exceptions, heatmaps or bigquery_export). See Using an mcp_ key over HTTP.
Query Parameters
Alternative to the X-Location-Id header for agency (ak_) keys. Ignored for secret (sk_) keys.
Pathname of the page, for example /pricing. A full URL is accepted and reduced to its pathname.
/pricingThe event that counts as advancing past this step. Omit it and "advanced" means the session saw a second page — the correct model for a bridge or advertorial page that carries no form.
form_submittedLookback window in days.
Headers
Location to scope the request to. Required for agency (ak_) keys on the event routes. Ignored for secret (sk_) keys, which resolve their own location, and not used by /export.