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    • Cursor

    The AI code editor. Cursor's BYOK (bring your own key) support lets the Chat / Agent panels route model requests through ByteSeek.

    Know Cursor's boundaries first (official wording)

    Cursor's official docs are explicit: custom keys only work with chat models, and Tab completion always uses Cursor's built-in models. Whether Chat / Agent / Edit work with a custom endpoint depends on your Cursor plan (see the support table below). For a coding agent that runs end-to-end on ByteSeek with no plan gating, use terminal tools such as Claude Code, Codex or OpenCode.

    Prerequisites

    • A reasonably recent Cursor build (the BYOK entry can vary by version/plan — defer to what your client actually shows)
    • A key supporting the OpenAI format created on the API keys page

    Setup (IDE)

    1. Press Ctrl + Shift + J (Cmd + Shift + J on macOS) to open Cursor Settings, then go to Models;
    2. Put your sk- key into the OpenAI API Key field — the field says OpenAI, but the key is sent to the custom endpoint you set below;
    3. Tick Override OpenAI Base URL and enter:
    https://tokens.byteseek.ai/v1

    Note: with /v1, no trailing slash. Cursor appends /chat/completions automatically.

    1. Click + Add Model and type the model ID you want (copy it from the model plaza; it must belong to the key's group). Also consider unticking same-name built-in models to avoid requests routing to the official channel;
    2. Click Verify;
    3. Pick the newly added model in the Chat panel's model dropdown and send a test message. Seeing the request in the usage logs means success.

    What routes through ByteSeek (per official sources)

    SurfaceVia ByteSeekNotes
    Chat (Ask mode)✅The BYOK baseline; staff replies confirm Ask is the only surface available without a paid plan
    Agent / Edit (incl. Inline Edit Cmd+K)✅ with a paid planOfficial staff reply (2026-07): BYOK custom models in Agent / Chat / Edit require an active Pro-or-higher subscription; without one, Cursor errors with "Agent and Edit rely on custom models that cannot be billed to an API key" and only Ask remains
    Tab completion❌Official docs: always uses Cursor's built-in models, never the custom key
    Cursor CLI (cursor-agent)❌The CLI offers no custom Base URL; CURSOR_API_KEY is a Cursor-official credential and models run on Cursor's channel. For terminals use Claude Code / Codex / OpenCode

    Cursor adjusts BYOK coverage between releases — where this table disagrees with your client, defer to the official docs and actual client behaviour.

    Notes

    • Requests are relayed via Cursor's backend: official docs state every request passes through Cursor's servers for final prompt building (the key is encrypted in transit and not persisted), so the custom endpoint must be publicly reachable (ByteSeek's is — nothing to do); local proxy addresses won't work directly.
    • Zero Data Retention does not apply: official docs are explicit that Cursor's ZDR policy does not apply with your own keys — data handling follows the service you connect (i.e. ByteSeek's privacy policy and the upstream vendors' policies).
    • Connection errors: on some networks HTTP/2 misbehaves — switch Settings → Network → HTTP Compatibility Mode to HTTP/1.1 and retry.
    • Known version bug: in 3.15.6 the OpenAI API Key and Override Base URL fields don't focus on mouse click (confirmed by staff on the official forum, fix rolling out) — click nearby, then press Tab to move focus into the field; fixed in newer builds.
    • Billing: BYOK requests are metered by ByteSeek (see Billing); your Cursor subscription is billed separately and independently.

    Common issues

    SymptomCause and fix
    Verify fails (401)Wrong or truncated key; re-copy from the API keys page
    Verify fails (404)Base URL wrong: it must be https://tokens.byteseek.ai/v1, with /v1, no trailing slash
    Model errors / no responseModel ID typo or not in the key's group — the model plaza is authoritative
    Still routing to official modelsConfirm the Override toggle is on and the selected model is the one you added; restart Cursor after changes
    "Agent and Edit rely on custom models…" errorWithout an active paid plan, BYOK only supports Ask mode; upgrade to Pro or higher, or switch to Ask
    Model snaps back to Auto/defaultThe client disables custom models when the subscription lapses or usage state is abnormal; check your plan in the Cursor dashboard
    403Client-restricted group or model not in group, see Error Codes
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