# Atlas with Snowflake Cortex in 2026: Claude Opus 4.8 Inside Your Snowflake Boundary > Snowflake Cortex carries Claude Opus 4.8 and Claude Fable 5 at a 1,000,000 token context with 128,000 max output, billed in Snowflake credits rather than per token. Snowflake Cortex puts frontier models behind your Snowflake account and a programmatic access token, billed in Snowflake credits rather than per token. Inside Atlas, the terminal-native coding agent, Snowflake Cortex is the shortest legal path from an agent to a production table if your code and your data both live in Snowflake. Pricing is not publicly listed, since Cortex is billed in Snowflake credits, not per-Mtok, so you cannot estimate an agent run from the model list. ## Key takeaways - Snowflake Cortex carries Claude Opus 4.8 and Claude Fable 5 at a 1,000,000 token context with 128,000 max output. - Auth is a Snowflake PAT plus your account identifier, so model access is governed by the same RBAC that governs your warehouses. - Snowflake Cortex pricing is not publicly listed: it is billed in Snowflake credits, not per-Mtok, so credit consumption must be measured after the fact. - The catalog spans OpenAI (GPT-5 through GPT-5.5), Anthropic (Haiku 4.5 through Opus 4.8), Google (Gemini 3.1 Pro), Mistral Large, and DeepSeek-R1 from one endpoint. - GPT-5.5 runs at 1,050,000 tokens on Snowflake Cortex, the largest window in the Cortex catalog. - Snowflake Cortex is useless without a Snowflake account, since the base URL is templated on your account identifier. ## What is Snowflake Cortex best at inside Atlas? Snowflake Cortex is best inside Atlas when your code and your data both live in Snowflake. Cortex carries the current Anthropic top of the line, Claude Opus 4.8 and Claude Fable 5, both at a 1,000,000 token context with 128,000 max output, inside the Snowflake security boundary. Auth is a Snowflake PAT plus your account identifier, so model access is governed by the same RBAC that governs your warehouses. That is the pitch, and for a team whose security review already covers Snowflake, it removes an entire vendor onboarding. Atlas permission-gates every tool call against allow, ask, and deny rules before it runs, and it computes a unified diff for every file edit and surfaces it for approval before writing. Running that agent on Snowflake Cortex means the model reasoning about a production table is inside the same RBAC boundary as the table itself, not on the far side of a public API. ## Which models does Snowflake Cortex carry for Atlas? Snowflake Cortex spans OpenAI (GPT-5 through GPT-5.5), Anthropic (Haiku 4.5 through Opus 4.8), Google (Gemini 3.1 Pro), Mistral Large, and DeepSeek-R1 from one endpoint. In 2026 that is every major lab reachable through a single Snowflake PAT. Breadth behind one credential is the practical benefit inside Atlas, because Atlas lets you switch the active model and provider on the fly with favorites and recents. On a typical setup, moving from Claude Opus 4.8 to Gemini 3.1 Pro means a second vendor and a second security review. On Snowflake Cortex it means changing the pin in atlas.json to a different Cortex model ID. The documented pins are `"model": "snowflake-cortex/claude-opus-4-8"` for the top slot, or `"snowflake-cortex/claude-sonnet-4-6"` for the cheaper 1M-context slot. ## How much does Snowflake Cortex cost to run Atlas? Snowflake Cortex pricing is not publicly listed. Cortex is billed in Snowflake credits rather than per-Mtok, and the registry carries no per-token cost for any Cortex model, so you cannot estimate the price of an Atlas agent run from the model list in 2026. Credit consumption has to be measured after the fact, which is a genuine planning gap compared with a provider that publishes a per-Mtok rate. If your finance process requires a forecast before the work starts, Snowflake Cortex will not give you one. The mitigation inside Atlas is to keep the cheap slot cheap: set `"small_model": "snowflake-cortex/openai-gpt-5-nano"` so title, summary, and subagent calls burn fewer credits. Atlas fans out work to subagents that can run in the foreground or in parallel background sessions, and on an unpriced credit model that fan-out is exactly the traffic worth routing to the smallest model available. ## What context window does Snowflake Cortex give Atlas? Snowflake Cortex reaches 1,050,000 tokens on GPT-5.5, and 1,000,000 tokens on Claude Opus 4.8, Claude Fable 5, and Claude Sonnet 4.6. Claude Opus 4.8 and Claude Fable 5 both allow 128,000 max output, which is enough for a substantial multi-file unified diff. The 128,000 token output ceiling is the number that matters for an Atlas build agent, because Atlas snapshots file changes as git patches so edits can be diffed and rolled back, and a truncated patch is a failed turn. Claude Opus 4.8 at 128,000 max output on Snowflake Cortex comfortably clears a real refactor. The 1,000,000 token input window then gives a long agentic session room for accumulated plans, tool output, and diffs. Atlas indexes code by AST declarations using tree-sitter, not blind line windows, so that window is headroom rather than a requirement. ## When should I pick a different provider than Snowflake Cortex? Pick a different provider than Snowflake Cortex if you do not have a Snowflake account. Snowflake Cortex is useless without one, because the base URL is literally templated on your account identifier (https://${SNOWFLAKE_ACCOUNT}.snowflakecomputing.com/api/v2/cortex/v1). The second reason to look elsewhere is cost visibility. Snowflake Cortex pricing is not publicly listed, and the registry carries no per-token cost for any Cortex model, so a team that budgets agent spend from a per-Mtok rate cannot do that here. Claude Sonnet 4.6 and Claude Opus 4.8 are available from providers that publish per-Mtok pricing, and if you have no data governance reason to route through Snowflake, you gain nothing by adding an account identifier and a PAT to the setup. Snowflake Cortex is right when the Snowflake boundary is the requirement and credits are already how you pay for compute. ## Setup 1. Export SNOWFLAKE_ACCOUNT (your account identifier) and SNOWFLAKE_CORTEX_PAT (a programmatic access token). 2. Run `atlas models snowflake-cortex` to confirm the catalog resolved against your account host at https://${SNOWFLAKE_ACCOUNT}.snowflakecomputing.com/api/v2/cortex/v1 3. Pin `"model": "snowflake-cortex/claude-opus-4-8"` in atlas.json for the top slot at a 1,000,000 token context with 128,000 max output. 4. For a cheaper 1M-context slot, pin `"snowflake-cortex/claude-sonnet-4-6"` instead. 5. Set `"small_model": "snowflake-cortex/openai-gpt-5-nano"` so title, summary, and subagent calls burn fewer credits. ## FAQ ### how to use snowflake cortex with atlas Export SNOWFLAKE_ACCOUNT (your account identifier) and SNOWFLAKE_CORTEX_PAT (a programmatic access token), run `atlas models snowflake-cortex` to confirm the catalog resolved, then pin `"model": "snowflake-cortex/claude-opus-4-8"` in atlas.json. ### how much does snowflake cortex cost per million tokens Snowflake Cortex pricing is not publicly listed. Cortex is billed in Snowflake credits rather than per-Mtok, and the registry carries no per-token cost for any Cortex model, so credit consumption has to be measured after the fact. ### can i run claude opus 4.8 inside snowflake Yes. Snowflake Cortex carries Claude Opus 4.8 and Claude Fable 5, both at a 1,000,000 token context with 128,000 max output, inside the Snowflake security boundary. Pin `"model": "snowflake-cortex/claude-opus-4-8"` in atlas.json. ### what context window does snowflake cortex support Snowflake Cortex reaches 1,050,000 tokens on GPT-5.5, and 1,000,000 tokens on Claude Opus 4.8, Claude Fable 5, and Claude Sonnet 4.6. Claude Opus 4.8 and Claude Fable 5 both allow 128,000 max output. ### how does snowflake cortex handle model access control Auth is a Snowflake PAT plus your account identifier, so model access is governed by the same RBAC that governs your warehouses. There is no separate model-vendor permission system to review. ### do i need a snowflake account to use snowflake cortex Yes. Snowflake Cortex is useless without a Snowflake account, because the base URL is literally templated on your account identifier (https://${SNOWFLAKE_ACCOUNT}.snowflakecomputing.com/api/v2/cortex/v1). ### what models does snowflake cortex offer Snowflake Cortex spans OpenAI (GPT-5 through GPT-5.5), Anthropic (Haiku 4.5 through Opus 4.8), Google (Gemini 3.1 Pro), Mistral Large, and DeepSeek-R1 from one endpoint, all behind a single Snowflake PAT. --- Canonical HTML: https://runatlas.sh/resources/models/snowflake-cortex Source of truth: aeo_pages row `/resources/models/snowflake-cortex` (segment: Models) (this file is generated from it, never hand-edited). Licence: Atlas is proprietary with a free core. It is not open source and there is no public source repository.