Auth Set

[MODE:SIDEEFFECTS] Tier: other. Not idempotent.

Overrides the API key and/or domain for the current MCP session. Validates the new credentials via a Ping (GET /api/me) before committing — so a typo in api_key cannot poison the session.

When to use

• Switching between production / staging / local in one MCP session.
• Multi-tenant HTTP MCP server — each session needs its own credentials.
• Temporary impersonation: switch to a service account, do work, switch back.

When NOT to use

• Stdio transports running on a single tenant — env vars (FIBE_API_KEY, FIBE_DOMAIN) are simpler.
• You only need to read with current creds — no override needed.

Inputs

Field	Type	Required	Notes
api_key	string	one of	New API key, e.g. fibe_test_...
domain	string	one of	New base domain, e.g. next.fibe.live
validate	bool	no	Default true; set false to skip the ping

At least one of api_key/domain must be set.

Output

{
  "ok": true,
  "api_key_set": true,
  "domain_set": false,
  "validated": true
}

Behavior

1. Snapshots the current session creds.
2. Applies the new ones (s.setSessionAuth).
3. If validate:true (default): rebuilds the SDK client and Pings /api/me. On failure, rolls back to the snapshot and returns validation failed (credentials NOT saved).
4. On success or validate:false, the override persists for the rest of the session.

Persistence scope

• Lives in MCP session state — not on disk.
• Only the current session sees the override; other sessions on the same server keep their own creds.
• Re-call to update further; pass api_key:"" is treated as "not set" (only domain changes), not as "clear".

Gotchas

• validate:false saves silently even on bad credentials — every later tool call returns 401 until you call fibe_auth_set again. Default is true for a reason.
• domain must include scheme-friendly host (next.fibe.live, rails.test:3000). Don't include https://.
• This affects the HTTP client the server uses — env vars (FIBE_*) are not mutated.
• Switching tenants does NOT clear the cached resource tools / catalog state; if you cached pipeline_ids, they remain valid only for the original session.

Related

• fibe_doctor — confirm new identity after switching.
• FIBE_API_KEY / FIBE_DOMAIN env vars — for stdio single-tenant setup.