docs: private-beta 403 message points at the web application form

api-reference/agent-errors.mdx

@@ -42,11 +42,11 @@
 | `422`  | Field-level validation failed                                            | Fix the fields listed in the error array.                                                                        |
 | `429`  | Public session creation is rate limited                                  | Back off and retry; per-agent and per-IP windows apply to [public agents](/agents/deploy/public-agents) only.    |
 | `502`  | An upstream dependency (conversation gateway, telephony provider) failed | Retry; for a failed phone-number purchase the row stays visible with status `error` and is safe to release.      |
 | `503`  | A platform dependency is temporarily unavailable                         | Retry with backoff.                                                                                              |
 
 ## 400 vs 422
 
 `422` is field-level validation: unknown fields (the public surface rejects them), length caps, enum values, invalid IANA timezones, dynamic-variable naming. `400` is semantic: an [override](/agents/deploy/authenticated-sessions#overrides) not enabled for the agent, mutually exclusive pagination parameters (`page` + `cursor`), an undecodable cursor, a page offset past 100,000 rows, or a knowledge upload that isn't UTF-8 plain text.
 
 Two quirks worth coding around:
 
@@ -55,14 +55,14 @@
 
 ## 403: what was refused
 
-| Message                                          | Cause                                                                                                       |
-| ------------------------------------------------ | ----------------------------------------------------------------------------------------------------------- |
-| `Agent is not public`                            | Anonymous session/widget request against an agent whose public switch is off.                               |
-| `Origin header is required for public agents`    | Anonymous request without an `Origin` header — browsers send it automatically, curl must set it.            |
-| `Origin not allowed`                             | The page's origin is not on the agent's [allowed origins](/agents/deploy/public-agents#origin-matching).    |
-| `Agent is unavailable`                           | The agent's owner can't serve public sessions right now; visitors deliberately can't tell why.              |
-| `Agent platform is not enabled for this account` | Creating agent resources requires Agents access on your account — contact support if you expect to have it. |
-| `Phone number limit reached for this team (N)`   | The team holds its maximum of live numbers; release one first.                                              |
+| Message                                                                                | Cause                                                                                                                 |
+| -------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------- |
+| `Agent is not public`                                                                  | Anonymous session/widget request against an agent whose public switch is off.                                         |
+| `Origin header is required for public agents`                                          | Anonymous request without an `Origin` header — browsers send it automatically, curl must set it.                      |
+| `Origin not allowed`                                                                   | The page's origin is not on the agent's [allowed origins](/agents/deploy/public-agents#origin-matching).              |
+| `Agent is unavailable`                                                                 | The agent's owner can't serve public sessions right now; visitors deliberately can't tell why.                        |
+| `Agent platform is in private beta. Apply for access at https://fish.audio/app/agents` | Creating agent resources requires beta access on your account — sign in and submit the application form at that link. |
+| `Phone number limit reached for this team (N)`                                         | The team holds its maximum of live numbers; release one first.                                                        |
 
 ## 404: anti-enumeration
 
@@ -87,7 +87,7 @@
 
 ## 5xx
 
 `502` names the failing upstream in the message: the conversation gateway (`Agent gateway is unreachable`) or the telephony provider (`Twilio refused the request: …`). Retrying is safe — a failed phone-number purchase leaves the row visible with status `error`, refunds the day charge, and can be released; a failed release keeps the number live so releasing again retries. `503` means a platform dependency was briefly unreachable; retry with backoff.
 
 ## Going further