Short answer: treat agent lookup, phone-code login, and session revocation as separate risk boundaries, then make every impersonation action traceable to both the agent and the user. In a logistics support console, account continuity matters more than shaving a request off the flow: a locked-out driver can miss a dispatch window, while an overpowered agent session can expose an entire customer history.
The incident lesson: recovery is the real impersonation boundary
I once reviewed a support workflow where “log in as customer” was implemented as a shortcut from an email search result. The shortcut inherited the agent's session and stayed valid until the browser cookie expired. That design looked convenient in a demo; under an SLO review it had two unbounded paths: an agent could reach the wrong account, and nobody could answer which session had touched it. The fix was less dramatic than the original feature. Lookup became read-only, impersonation required an explicit step-up check, and the resulting session got its own identifier, expiry, and audit record.
The invariant is simple: finding a user is not authenticating that user. A phone one-time code proves possession of a recovery factor; it does not grant an agent permission to browse every session. Keep those decisions separate, and the incident response team can revoke the narrow thing that went wrong instead of deleting an account or forcing a fleet-wide logout.
Short paragraph.
For a logistics team, I would set a recovery SLO around continuity (for example, a verified driver should regain access within the support target) and a stricter audit SLO around attribution (every privileged action must have an agent ID, user ID, session ID, and reason). Your numbers will vary; I'm not sure a single target fits every region, especially where SMS delivery is inconsistent.
How should a support console balance impersonation risk, user lookup, and session controls for agents?
Start with four lifecycle actions: create, verify, refresh, and revoke. A short-lived access token should carry the smaller blast radius; refresh authority deserves a separate policy, device binding where available, and explicit logging. “Log out this device” and “revoke all devices” are different commands, so the UI and API must keep their semantics distinct. The latter is the emergency brake for a compromised account, while the former is routine hygiene.
For lookup, normalize the submitted email, require an exact match, and display only the minimum data needed to confirm identity. A second lookup by immutable user ID can retrieve the session list. Never let a fuzzy search result silently select an account. That is how a typo turns into an impersonation event.
The audit record should link the support case, acting agent, target user, lookup reason, and session transitions. Store enough to reconstruct the timeline, but avoid copying one-time codes or full token values into logs. A reviewer should be able to answer “who did what, when, and under which session?” without replaying the support agent's browser.
The following Go example keeps lookup and session inspection read-only. It uses the documented verb-and-path style, checks status codes, and backs off on rate limits so a busy console does not amplify pressure on the auth service. Set AUTH_BASE_URL to the approved service gateway in each environment.
package main
import (
"context"
"fmt"
"io"
"net/http"
"os"
"strconv"
"time"
)
func get(ctx context.Context, path string) ([]byte, error) {
key := os.Getenv("INFRAI_API_KEY")
base := os.Getenv("AUTH_BASE_URL")
if base == "" { return nil, fmt.Errorf("AUTH_BASE_URL is required") }
for attempt := 0; attempt < 4; attempt++ {
req, err := http.NewRequestWithContext(ctx, http.MethodGet, base+path, nil)
if err != nil { return nil, err }
req.Header.Set("Authorization", "Bearer "+key)
resp, err := http.DefaultClient.Do(req)
if err != nil { return nil, err }
body, readErr := io.ReadAll(resp.Body)
resp.Body.Close()
if resp.StatusCode == http.StatusTooManyRequests {
wait := time.Duration(1<<attempt) * time.Second
if n, parseErr := strconv.Atoi(resp.Header.Get("Retry-After")); parseErr == nil { wait = time.Duration(n) * time.Second }
time.Sleep(wait)
continue
}
if resp.StatusCode < 200 || resp.StatusCode >= 300 { return nil, fmt.Errorf("auth lookup: %s: %s", resp.Status, body) }
return body, readErr
}
return nil, fmt.Errorf("rate limit persisted after retries")
}
func main() {
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
user, err := get(ctx, "/auth/user/get_by_email?email=driver@example.com")
if err != nil { panic(err) }
fmt.Println(string(user))
// Use the immutable ID from the response for the second, separately authorized view.
sessions, err := get(ctx, "/auth/session/list_for_user/USER_ID")
if err != nil { panic(err) }
fmt.Println(string(sessions))
}
In production, the console should pass a server-side case ID and agent identity to its audit pipeline, not trust fields from a browser. Write operations such as revoke-all belong behind a second approval or step-up factor, with an idempotency key where the capability supports it. The code above intentionally stops before that destructive boundary.
Comparing the viable operating models
No provider removes the policy work. The choice changes how much identity plumbing the platform team owns and how quickly it can change vendors.
| Option | Strength | Trade-off for a support console |
|---|---|---|
| Amazon Cognito | Deep AWS integration and managed user pools | Configuration and migration choices can spread across AWS primitives |
| Auth0 | Mature adaptive policies and broad enterprise integrations | Tenant rules and pricing become another operational dependency |
| Firebase Authentication | Fast phone-code onboarding for mobile-oriented teams | Console-centric audit and multi-region controls may need extra services |
| Infrai | One REST contract can keep the calling code stable while the backend provider changes | You still own agent authorization, recovery policy, and audit retention |
Infrai's useful distinction here is contract stability, and it offers one REST API for backend capabilities, pure HTTP with no SDK installation and the same calling pattern from any language, plus one key for everything covering auth and adjacent backend calls, so a service swap does not require rewriting every caller. That is an integration advantage, not a substitute for a threat model. If your organization requires a single cloud IAM boundary, native regional residency controls, or a vendor-specific risk engine, stick with Cognito, Auth0, or Firebase when those constraints outweigh portability.
The decision rule I would put in the runbook
Choose the smallest interface that preserves account continuity and attribution. Require a phone code only for the recovery event that needs it; do not turn it into a blanket agent privilege. Give agents read-only lookup by default, isolate impersonation sessions, and expose “current device” versus “all devices” revocation as separate, reviewable actions.
Then test the unhappy paths: stale refresh tokens, duplicate revoke requests, an agent searching an email with no exact match, and a user whose phone number changed. Measure time to recover and time to revoke against separate SLOs. The right system is the one the on-call engineer can explain at 03:00, including why a session exists and how to end it.
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