The short version
mythos sets only the cookies and browser storage it needs to run: keeping you signed in, protecting sign-in and account-connection flows from forgery, and powering the live preview. Everything we set ourselves is first-party. We set no advertising cookies, no third-party analytics cookies, and no tracking pixels — so there is nothing to opt out of in the ad-tech sense.
Every item we store on your device is listed on this page, with its lifetime and what it is for.
Browser storage we use
Beyond cookies, mythos uses localStorage for durable recovery and preferences, sessionStorage for tab-scoped recovery, and IndexedDB for attachment bodies that are too large for key-value storage. Names containing angle-bracket placeholders describe a key family rather than a literal key; for example, one owner-scoped key can be created for each account.
A record can reach its stated logical expiry and stop being read before the browser physically deletes its bytes. Where cleanup is best-effort, the duration row says so. You can remove all remaining records at any time by clearing site data for mythos.new.
localStorage keys set by mythos
| Storage item and duration | Purpose |
|---|---|
mythos_cookie_notice_ack_v1Until you clear browser storage | Remembers that you dismissed the cookie notice and the choice you made. |
mythos_pending_prompt_v3Usable for up to 24 hours and cleared immediately after a durable owner-bound handoff claim is confirmed. Expired or invalid copies are ignored and may remain until you clear browser storage | Keeps the project prompt you typed on the landing page so it survives the sign-in redirect. |
keek_pending_promptLegacy only; no longer read or created. Removed when the current prompt flow next accesses browser storage, or when you clear browser storage | Retired landing-prompt key kept only in cleanup code so a cached pre-owner-binding app version cannot pass its value into the current protocol. |
mythos_post_auth_prompt_handoff_durable_v2Usable for up to 15 minutes. The first signed-in account claims it under a browser lock; it is cleared only after exact project-success settlement. Expired or invalid copies are ignored and may remain until you clear browser storage | Paired durable copy of the post-sign-in prompt handoff. It is reconciled with the tab copy so a partial owner claim cannot expose the prompt to another account. |
mythos_post_auth_prompt_handoff_ownerUsable for up to 15 minutes. Cleared with the exact prompt handoff after project creation or during a later expired-handoff cleanup; otherwise it remains until you clear browser storage | Stores only the signed-in account ID and opaque handoff ID (not the prompt) so an interrupted dashboard navigation can rediscover that account’s owner-bound prompt. |
mythos_post_auth_prompt_handoff_durableLegacy only; no longer read or created. Removed when the current prompt flow next accesses browser storage, or when you clear browser storage | Retired durable handoff key retained only for rolling-deploy cleanup. Current handoffs use an isolated versioned key. |
mythos_pending_remixA pre-submit choice is usable for up to 15 minutes; a submitted operation for up to 24 hours. Cleared after creation, insufficient-credit settlement, or terminal failure; expired or invalid copies are ignored and may remain until you clear browser storage | Remembers the template remix choice and, after submission, the exact idempotent operation so an interrupted request can be reconciled safely. |
keek_pending_referralCleared after the referral is accepted or definitively rejected. Network errors and explicitly temporary outages keep it for a later sign-in retry; otherwise it remains until you clear browser storage | Stores the referral code from a link you followed so the person who invited you can be credited. |
mythos_pending_blank_project:<account-id>Usable for up to 24 hours. Cleared after the project is created or converted into a terminal-failure record; expired or invalid copies are ignored and may remain until exact cleanup or you clear browser storage | One owner-scoped recovery record per signed-in account for an interrupted blank-project creation, including the prompt, template, attachment digest, and idempotency identity. |
mythos_pending_blank_project_failure:<account-id>Usable for up to 24 hours. Cleared when the exact failure is dismissed or superseded by a successful retry; expired or invalid owner records are removed during later recovery when browser storage is available | One owner-scoped terminal-failure notice per account so a failed project request can be shown or retried without exposing another account’s draft. |
mythos_pending_blank_projectRolling-deploy compatibility only. A saved intent or safety marker is usable for no more than 24 hours; stale copies are ignored and may remain until a later compatibility write or you clear browser storage | Legacy singleton retained temporarily as a fail-closed migration fence while blank-project recovery moves to owner-scoped keys. |
mythos.pending-attachments.v1.<account-id>.<project-id>Ready metadata is usable for up to 24 hours. Acknowledgement or expiry replaces it with a small consumed or unavailable marker; terminal project failure deletes it. A marker can otherwise remain until you clear browser storage | Metadata only for an attachment handoff: account and project IDs, timestamps, item count, status, and a payload fingerprint. Attachment bodies are kept separately in IndexedDB. |
mythos:agent-run:v1:<project-id>No fixed expiry. Replaced when another run becomes the project focus; cleared when you clear the run, when the referenced run no longer exists, or when you clear browser storage. Invalid copies are removed during restore | Stores one project-scoped run ID and its last confirmed event cursor so the workspace can restore the durable run after a reload and safely replay its event stream. It does not store the chat transcript. |
mythos:agent-paid-submission:v2:<project-id>No fixed expiry. Cleared after the server accepts the run or authoritatively rejects it. Network errors, server errors, and unknown outcomes keep the exact request for idempotent replay; malformed or oversized copies are removed during reconciliation | Stores one project-scoped idempotent Create, Plan approval, or Continue request, including its operation key, scope fingerprint, and payload, so an uncertain paid admission is replayed exactly rather than submitted as different work. |
mythos:admin-credit-adjust:<account-id>No fixed expiry. Cleared after confirmed success or a known terminal rejection; an outcome-unknown operation is kept for exact replay until an administrator reconciles it or clears browser storage | Super-admin only. Preserves an idempotent credit adjustment, including its account, amount, reason, and operation key, across reloads. |
mythos:admin-rollout:preview-sync:v1No fixed expiry. Cleared after confirmed success or a known terminal rejection; an outcome-unknown operation is kept for exact replay until an administrator reconciles it or clears browser storage | Super-admin only. Preserves an idempotent preview-sync rollout change across reloads so an uncertain server outcome is not submitted as a different operation. |
sessionStorage keys set by mythos
| Storage item and duration | Purpose |
|---|---|
mythos_post_auth_prompt_handoff_v2Usable for up to 15 minutes. The first signed-in account claims it under a browser lock; it is cleared only after exact project-success settlement or when the tab session ends. Expired or invalid copies are ignored | Tab-scoped half of the owner-bound landing-page prompt handoff. It must agree with the durable copy before the prompt is shown. |
mythos_post_auth_prompt_handoffLegacy only; no longer read or created. Removed when the current prompt flow next accesses this tab, or when the tab session ends | Retired tab handoff key retained only for rolling-deploy cleanup. A server protocol fence strips handoff nonces emitted by cached app versions. |
mythos-preview-bootstrap:<path-and-query>Cleared when the preview shell boots successfully; otherwise removed when the tab session ends | Keeps a bounded retry-attempt number for one preview URL across reloads so automatic recovery remains rate-limited. |
IndexedDB storage used by mythos
| Storage item and duration | Purpose |
|---|---|
mythos-local-handoffs / pending_attachmentsAttachment bodies are usable for up to 24 hours and are removed after exact server acknowledgement, terminal project-create failure, expiry cleanup, or when you clear browser storage | IndexedDB database and object store holding attachment bodies and integrity metadata while an interrupted first project creation is safely handed to the server. |
Analytics, advertising, and error monitoring
We run no third-party analytics (no Google Analytics, no session recording) and no advertising technology of any kind. Two kinds of telemetry exist, and neither uses cookies nor sets a persistent browser identifier:
- Performance and error beacons — anonymous reports (page timing, a JavaScript error) posted to our own endpoints to keep the product fast and working.
- Error monitoring (Sentry) — when something breaks, a technical error report is sent through our own domain to Sentry (EU) so we can fix it. The Sentry browser SDK sets no cookies here, session replay is disabled, and reports do not include personal data by default.
Changes and contact
If we add a cookie or storage key, change a lifetime, or introduce a third party that can set cookies, we will update this page and the date shown above.
Questions about our use of cookies: privacy@mythos.new.