> ## Documentation Index > Fetch the complete documentation index at: https://superform-cb7ef652-docs-fix-strategy-engine-drift.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Strategy DSL > Rule-tree grammar, expression syntax, variables, and validation behavior for SuperVault strategies. The Strategy DSL has two layers: * A boolean `rules` tree that decides whether a strategy should fire. * Numeric expressions, such as `size_expr`, that decide how much the strategy should send to OMS. ## Rule Nodes | Node | Meaning | Shape | | ------ | ---------------------------------- | -------------------------------------------------------------------- | | `EXPR` | Evaluate one boolean expression. | `{ "type": "EXPR", "expr": "vault_free_assets > 0.10 * vault_tvl" }` | | `AND` | All child rules must pass. | `{ "type": "AND", "children": [...] }` | | `OR` | At least one child rule must pass. | `{ "type": "OR", "children": [...] }` | | `NOT` | Negates one child rule. | `{ "type": "NOT", "child": {...} }` | | `VOTE` | N-of-M child rules must pass. | `{ "type": "VOTE", "threshold": 2, "children": [...] }` | Use shallow rule trees when possible. Deep trees are harder to review and usually indicate that two strategy lanes should be split. ## Expression Guidelines Expressions are evaluated by the Strategy Engine against the current vault snapshot. | Pattern | Use | | -------------------------------------- | ----------------------------------------------- | | `vault_free_assets > 0.10 * vault_tvl` | Prefer multiplication over division for ratios. | | `ys_0xabc_amount > 0` | Target source holds a deployed position. | | `ys_0xabc_apy > 0.05` | Source yield is above a threshold. | | `tick_hour >= 8 && tick_hour < 20` | Restrict actions to a UTC time window. | In the examples above, `0xabc` stands in for the full lowercase yield-source address. Avoid division in rule expressions unless the denominator is guaranteed non-zero. The validator dry-runs expressions against an empty snapshot to catch type and parse errors, which means division by zero can reject a strategy before it is saved. ## Common Variables Variable availability depends on the datafeed and vault snapshot. Common families include: | Family | Examples | Meaning | | ------------------ | ------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Vault state | `vault_free_assets`, `vault_tvl`, `vault_total_supply`, `vault_pps` | Vault-level balances, supply, and price-per-share. | | Redeem queue | `vault_redeem_queue_count`, `vault_redeem_queue_value` | Pending redemption pressure on the vault. | | Yield source state | `ys_
_amount`, `ys_
_shares`, `ys_
_pps`, `ys_
_apy`, `ys_
_tvl` | Per-source position (asset amount and shares), price-per-share, yield, and liquidity. Valid metric suffixes: `amount`, `shares`, `pps`, `apy`, `base_apy`, `reward_apy`, `tvl`. | | Price | `price` | Latest price sample feeding indicators. | | Tick context | `tick_unix`, `tick_unix_ms`, `tick_hour`, `tick_minute`, `tick_second`, `tick_dow`, `tick_day`, `tick_month`, `tick_year` | UTC wall-clock fields injected each tick. No relative/age suffixes exist. | | Merkl aggregates | `merkl_
_amount`, `merkl_
_value_usd` | Claimable Merkl reward aggregates. | | Indicators | Custom aliases configured in `indicators` | Derived signals such as moving averages or momentum scores. | These are the canonical engine snapshot keys. Per-source (`ys_`) and Merkl (`merkl_`) keys require a full lowercase `0x` address and one of the known metric suffixes; any unknown identifier is rejected at create/update time with a position-tagged error. When in doubt, inspect the validation error and the engine snapshot shown in [Intent History](/operate/ui/intent-history). ## `size_expr` `action_config.size_expr` is numeric and must evaluate to a positive amount in the **hook's input units**, which depend on the action: * `DEPOSIT` (e.g. `ApproveAndDeposit4626VaultHook`) sizes in underlying **asset** base units. * `WITHDRAWAL` (`Redeem4626VaultHook`) sizes in yield-source **share** base units, because the hook calls `redeem(shares)`. Rules for sizing: * It must be positive at runtime; a value of `0` or less is dropped before reaching OMS. * It should be bounded by available liquidity or the held position. * It should match the action's unit (assets for deposit, shares for redeem) and direction. * It should be easy to audit from dashboard numbers. Examples: ```text theme={null} vault_free_assets ``` ```text theme={null} min(vault_free_assets, 0.05 * vault_tvl) ``` ```text theme={null} 0.5 * ys_0xabc_shares ``` Do not convert an asset target to shares by dividing by `ys_
_pps`. The validator dry-runs `size_expr` against an empty snapshot where `pps` is `0`, so the division is rejected at create/update time. Size redeems directly off `ys_
_shares` instead. ## Conviction Config `conviction_config` controls how many passing ticks are required before a strategy publishes. | Mode | Meaning | | ----------------- | ------------------------------------------------------------------------------------------------ | | `BINARY` | One passing evaluation is enough. This is the default when `conviction_config` is omitted. | | Expression-scored | When `conviction_config.expr` is set, a numeric score gates publishing instead of a single pass. | Use `BINARY` for simple operational gates. Add stronger conviction only when false positives are expensive and delayed action is acceptable. ## Validation Timing The Strategy Engine validates at create and update time: * JSON shape and required fields. * Known action names and lane compatibility. * Expression parseability. * Basic dry-run evaluation. * Address formatting. * Version conflicts on update. Validation does **not** cover everything. In particular, it does not confirm that `execution_name` exists in the live hook registry, and it does not check that `size_expr` units match the hook (asset wei vs share wei). Verify both against [Action Config](/operate/strategy/action-config). Runtime checks still apply after validation. A strategy can save successfully and later fail to publish if it lacks a session key, merkle proof, active yield source, or executable OMS route.