Models and versioning

Mouse serves one model family (mouse-1) behind immutable, date-stamped snapshot IDs. Every decision response echoes the exact snapshot ID that scored the request in both the JSON body (model) and the Mouse-Model-Version HTTP header.

Active models and aliases

Query GET /v1/models to inspect all active snapshots and alias mappings:

Alias	Resolves to snapshot	Max state tokens	Modalities	Status
mouse-1	mouse-preview-2026-10-13	65,536	["text"]	Preview
mouse	mouse-preview-2026-10-13	65,536	["text"]	Preview

You can pass either an alias ("mouse-1", "mouse") or the immutable snapshot ID ("mouse-preview-2026-10-13") in the model field of POST /v1/systemone and POST /v1/calibrations.

Versioning and pinning policy

1. Immutable snapshots: Once a snapshot ID such as mouse-preview-2026-10-13 is published, its weights, tokenizer, rendering format, and scoring numerics never change.
2. Always echoed: Even when you request model: "mouse-1", the response body's model field and the Mouse-Model-Version header always return the concrete snapshot ID ("mouse-preview-2026-10-13"). Log this value alongside your application telemetry.
3. When to pin a snapshot ID: If you fit a calibration profile (calp1.) or tune custom confidence thresholds against your validation set, pin model: "mouse-preview-2026-10-13" in production. Calibration profiles are bound to the snapshot they were fitted on and return 409 profile_model_mismatch if used with a different snapshot.
4. 30-day alias notice & 12-month support window: Aliases (mouse-1, mouse) advance to newer snapshots with at least 30 days' advance notice. Superseded snapshots remain live for at least 12 months after their successor ships, with retire_after populated in GET /v1/models.

Model design

mouse-1 is a proprietary decision model purpose-built for agent-harness control: tool routing, action-gate safety, option-order invariance (<1% order flip rate), and resistance to planted prompt injections in untrusted state (0% flip rate on held-out injection suites).