## Estimate Cost

`small_molecule.library_screen.estimate_cost(LibraryScreenEstimateCostParams**kwargs)  -> LibraryScreenEstimateCostResponse`

**post** `/compute/v1/small-molecule/library-screen/estimate-cost`

Estimate the cost of a small molecule library screen without creating any resource or consuming GPU.

### Parameters

- `molecules: Iterable[Molecule]`

  List of small molecules to screen.

  - `smiles: str`

    SMILES string of the molecule

  - `id: Optional[str]`

    Optional identifier for this molecule

- `target: Target`

  Target protein with binding pocket for small molecule design or screening

  - `entities: Iterable[TargetEntity]`

    Protein entities defining the target structure. Each entity represents a protein chain.

    - `chain_ids: SequenceNotStr[str]`

      Chain IDs for this entity

    - `type: Literal["protein"]`

      - `"protein"`

    - `value: str`

      Amino acid sequence (one-letter codes)

    - `cyclic: Optional[bool]`

      Whether the sequence is cyclic

    - `modifications: Optional[Iterable[TargetEntityModification]]`

      Post-translational modifications. Optional; defaults to an empty list when omitted.

      - `class TargetEntityModificationCcdModification: …`

        - `residue_index: int`

          0-based index of the residue to modify

        - `type: Literal["ccd"]`

          - `"ccd"`

        - `value: str`

          CCD code from RCSB PDB (e.g. 'MSE' for selenomethionine, 'SEP' for phosphoserine)

      - `class TargetEntityModificationSmilesModification: …`

        - `residue_index: int`

          0-based index of the residue to modify

        - `type: Literal["smiles"]`

          - `"smiles"`

        - `value: str`

          SMILES string for the modification

  - `bonds: Optional[Iterable[TargetBond]]`

    Covalent bond constraints between atoms in the target complex. Atom-level ligand references currently support ligand_ccd only; ligand_smiles is unsupported.

    - `atom1: TargetBondAtom1`

      Ligand atom reference. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

      - `class TargetBondAtom1LigandAtom: …`

        Ligand atom reference. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

        - `atom_name: str`

          Standardized atom name (verifiable in CIF file on RCSB). Atom-level references to ligand_smiles entities are currently unsupported; use ligand_ccd instead.

        - `chain_id: str`

          Chain ID containing the atom

        - `type: Literal["ligand_atom"]`

          - `"ligand_atom"`

      - `class TargetBondAtom1PolymerAtom: …`

        - `atom_name: str`

          Standardized atom name (verifiable in CIF file on RCSB)

        - `chain_id: str`

          Chain ID containing the atom

        - `residue_index: int`

          0-based residue index

        - `type: Literal["polymer_atom"]`

          - `"polymer_atom"`

    - `atom2: TargetBondAtom2`

      Ligand atom reference. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

      - `class TargetBondAtom2LigandAtom: …`

        Ligand atom reference. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

        - `atom_name: str`

          Standardized atom name (verifiable in CIF file on RCSB). Atom-level references to ligand_smiles entities are currently unsupported; use ligand_ccd instead.

        - `chain_id: str`

          Chain ID containing the atom

        - `type: Literal["ligand_atom"]`

          - `"ligand_atom"`

      - `class TargetBondAtom2PolymerAtom: …`

        - `atom_name: str`

          Standardized atom name (verifiable in CIF file on RCSB)

        - `chain_id: str`

          Chain ID containing the atom

        - `residue_index: int`

          0-based residue index

        - `type: Literal["polymer_atom"]`

          - `"polymer_atom"`

  - `constraints: Optional[Iterable[TargetConstraint]]`

    Structural constraints (pocket and contact). Atom-level ligand references currently support ligand_ccd only; ligand_smiles is unsupported.

    - `class TargetConstraintPocketConstraint: …`

      Constrains the binder to interact with specific pocket residues on the target.

      - `binder_chain_id: str`

        Chain ID of the binder molecule

      - `contact_residues: Dict[str, Iterable[int]]`

        Binding pocket residues keyed by chain ID. Each key is a chain ID (e.g. "A") and the value is an array of 0-indexed residue indices that define the pocket on that chain.

      - `max_distance_angstrom: float`

        Maximum allowed distance in Angstroms between binder and pocket residues. Typical range: 4-8 A.

      - `type: Literal["pocket"]`

        - `"pocket"`

      - `force: Optional[bool]`

        Whether to force the constraint

    - `class TargetConstraintContactConstraint: …`

      Contact constraint between two tokens. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

      - `max_distance_angstrom: float`

        Maximum distance in Angstroms

      - `token1: TargetConstraintContactConstraintToken1`

        Ligand contact token. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

        - `class TargetConstraintContactConstraintToken1PolymerContactToken: …`

          - `chain_id: str`

            Chain ID

          - `residue_index: int`

            0-based residue index

          - `type: Literal["polymer_contact"]`

            - `"polymer_contact"`

        - `class TargetConstraintContactConstraintToken1LigandContactToken: …`

          Ligand contact token. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

          - `atom_name: str`

            Atom name. Atom-level references to ligand_smiles entities are currently unsupported; use ligand_ccd instead.

          - `chain_id: str`

            Chain ID

          - `type: Literal["ligand_contact"]`

            - `"ligand_contact"`

      - `token2: TargetConstraintContactConstraintToken2`

        Ligand contact token. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

        - `class TargetConstraintContactConstraintToken2PolymerContactToken: …`

          - `chain_id: str`

            Chain ID

          - `residue_index: int`

            0-based residue index

          - `type: Literal["polymer_contact"]`

            - `"polymer_contact"`

        - `class TargetConstraintContactConstraintToken2LigandContactToken: …`

          Ligand contact token. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

          - `atom_name: str`

            Atom name. Atom-level references to ligand_smiles entities are currently unsupported; use ligand_ccd instead.

          - `chain_id: str`

            Chain ID

          - `type: Literal["ligand_contact"]`

            - `"ligand_contact"`

      - `type: Literal["contact"]`

        - `"contact"`

      - `force: Optional[bool]`

        Whether to force the constraint

  - `pocket_residues: Optional[Dict[str, Iterable[int]]]`

    Binding pocket residues, keyed by chain ID. Each key is a chain ID (e.g. "A") and the value is an array of 0-indexed residue indices that define the binding pocket on that chain. When provided, these residues guide pocket extraction and add a derived pocket constraint during affinity predictions. That derived constraint remains separate from any explicit pocket constraints in target.constraints. When omitted, the model auto-detects the pocket.

  - `reference_ligands: Optional[SequenceNotStr[str]]`

    Reference ligands as SMILES strings that help the model identify the binding pocket. When omitted, a set of drug-like default ligands is used for pocket detection.

- `idempotency_key: Optional[str]`

  Client-provided key to prevent duplicate submissions on retries

- `molecule_filters: Optional[MoleculeFilters]`

  Molecule filtering configuration. Controls both Boltz built-in SMARTS filtering and custom filters.

  - `boltz_smarts_catalog_filter_level: Optional[Literal["recommended", "extra", "aggressive", "disabled"]]`

    Controls the stringency of Boltz's built-in SMARTS structural alert filtering, which removes molecules matching known problematic substructures. 'recommended' (default): applies a curated set of alerts balancing safety and hit rate. 'extra': adds additional alerts beyond the recommended set for stricter filtering. 'aggressive': applies the most comprehensive alert set — may reject viable molecules. 'disabled': turns off Boltz SMARTS filtering entirely; only custom_filters will be applied.

    - `"recommended"`

    - `"extra"`

    - `"aggressive"`

    - `"disabled"`

  - `custom_filters: Optional[Iterable[MoleculeFiltersCustomFilter]]`

    Custom filters to apply. Molecules must pass all filters (AND logic).

    - `class MoleculeFiltersCustomFilterLipinskiFilter: …`

      Lipinski's Rule of Five filter. Rejects molecules that violate drug-likeness criteria based on molecular weight, LogP, hydrogen bond donors, and hydrogen bond acceptors.

      - `max_hba: float`

        Maximum number of hydrogen bond acceptors. Lipinski threshold: 10

      - `max_hbd: float`

        Maximum number of hydrogen bond donors. Lipinski threshold: 5

      - `max_logp: float`

        Maximum LogP. Lipinski threshold: 5

      - `max_mw: float`

        Maximum molecular weight (Da). Lipinski threshold: 500

      - `type: Literal["lipinski_filter"]`

        - `"lipinski_filter"`

      - `allow_single_violation: Optional[bool]`

        If true, one rule violation is allowed (classic Rule of Five). Defaults to false (all rules must pass).

    - `class MoleculeFiltersCustomFilterRdkitDescriptorFilter: …`

      Filter molecules by RDKit molecular descriptors. Each descriptor is constrained to a min/max range. Only descriptors you provide are checked — omitted descriptors are unconstrained.

      - `type: Literal["rdkit_descriptor_filter"]`

        - `"rdkit_descriptor_filter"`

      - `fraction_csp3: Optional[MoleculeFiltersCustomFilterRdkitDescriptorFilterFractionCsp3]`

        Min/max range constraint for an RDKit molecular descriptor

        - `max: Optional[float]`

          Maximum allowed value (inclusive)

        - `min: Optional[float]`

          Minimum allowed value (inclusive)

      - `mol_logp: Optional[MoleculeFiltersCustomFilterRdkitDescriptorFilterMolLogp]`

        Min/max range constraint for an RDKit molecular descriptor

        - `max: Optional[float]`

          Maximum allowed value (inclusive)

        - `min: Optional[float]`

          Minimum allowed value (inclusive)

      - `mol_wt: Optional[MoleculeFiltersCustomFilterRdkitDescriptorFilterMolWt]`

        Min/max range constraint for an RDKit molecular descriptor

        - `max: Optional[float]`

          Maximum allowed value (inclusive)

        - `min: Optional[float]`

          Minimum allowed value (inclusive)

      - `num_aromatic_rings: Optional[MoleculeFiltersCustomFilterRdkitDescriptorFilterNumAromaticRings]`

        Min/max range constraint for an RDKit molecular descriptor

        - `max: Optional[float]`

          Maximum allowed value (inclusive)

        - `min: Optional[float]`

          Minimum allowed value (inclusive)

      - `num_h_acceptors: Optional[MoleculeFiltersCustomFilterRdkitDescriptorFilterNumHAcceptors]`

        Min/max range constraint for an RDKit molecular descriptor

        - `max: Optional[float]`

          Maximum allowed value (inclusive)

        - `min: Optional[float]`

          Minimum allowed value (inclusive)

      - `num_h_donors: Optional[MoleculeFiltersCustomFilterRdkitDescriptorFilterNumHDonors]`

        Min/max range constraint for an RDKit molecular descriptor

        - `max: Optional[float]`

          Maximum allowed value (inclusive)

        - `min: Optional[float]`

          Minimum allowed value (inclusive)

      - `num_heteroatoms: Optional[MoleculeFiltersCustomFilterRdkitDescriptorFilterNumHeteroatoms]`

        Min/max range constraint for an RDKit molecular descriptor

        - `max: Optional[float]`

          Maximum allowed value (inclusive)

        - `min: Optional[float]`

          Minimum allowed value (inclusive)

      - `num_rings: Optional[MoleculeFiltersCustomFilterRdkitDescriptorFilterNumRings]`

        Min/max range constraint for an RDKit molecular descriptor

        - `max: Optional[float]`

          Maximum allowed value (inclusive)

        - `min: Optional[float]`

          Minimum allowed value (inclusive)

      - `num_rotatable_bonds: Optional[MoleculeFiltersCustomFilterRdkitDescriptorFilterNumRotatableBonds]`

        Min/max range constraint for an RDKit molecular descriptor

        - `max: Optional[float]`

          Maximum allowed value (inclusive)

        - `min: Optional[float]`

          Minimum allowed value (inclusive)

      - `tpsa: Optional[MoleculeFiltersCustomFilterRdkitDescriptorFilterTpsa]`

        Min/max range constraint for an RDKit molecular descriptor

        - `max: Optional[float]`

          Maximum allowed value (inclusive)

        - `min: Optional[float]`

          Minimum allowed value (inclusive)

    - `class MoleculeFiltersCustomFilterSmartsCustomFilter: …`

      Filter molecules by custom SMARTS patterns. Molecules matching any pattern are rejected.

      - `patterns: SequenceNotStr[str]`

        SMARTS patterns. Molecules matching any pattern are rejected.

      - `type: Literal["smarts_custom_filter"]`

        - `"smarts_custom_filter"`

    - `class MoleculeFiltersCustomFilterSmartsCatalogFilter: …`

      Filter molecules using a predefined SMARTS catalog of structural alerts.

      - `catalog: Literal["PAINS", "PAINS_A", "PAINS_B", 11 more]`

        Predefined SMARTS catalog to apply. PAINS, BRENK, ChEMBL, and NIH catalogs reject known problematic substructures.

        - `"PAINS"`

        - `"PAINS_A"`

        - `"PAINS_B"`

        - `"PAINS_C"`

        - `"BRENK"`

        - `"CHEMBL"`

        - `"CHEMBL_BMS"`

        - `"CHEMBL_Dundee"`

        - `"CHEMBL_Glaxo"`

        - `"CHEMBL_Inpharmatica"`

        - `"CHEMBL_LINT"`

        - `"CHEMBL_MLSMR"`

        - `"CHEMBL_SureChEMBL"`

        - `"NIH"`

      - `type: Literal["smarts_catalog_filter"]`

        - `"smarts_catalog_filter"`

    - `class MoleculeFiltersCustomFilterSmilesRegexFilter: …`

      Filter molecules by regex patterns on their SMILES representation.

      - `patterns: SequenceNotStr[str]`

        Regex patterns applied to SMILES strings. Molecules matching any pattern are rejected.

      - `type: Literal["smiles_regex_filter"]`

        - `"smiles_regex_filter"`

- `workspace_id: Optional[str]`

  Target workspace ID (admin keys only; ignored for workspace keys)

### Returns

- `class LibraryScreenEstimateCostResponse: …`

  Estimate response with monetary values encoded as decimal strings to preserve precision.

  - `breakdown: Breakdown`

    Cost breakdown for the billed application.

    - `application: Literal["structure_and_binding", "small_molecule_design", "small_molecule_library_screen", 3 more]`

      - `"structure_and_binding"`

      - `"small_molecule_design"`

      - `"small_molecule_library_screen"`

      - `"protein_design"`

      - `"protein_library_screen"`

      - `"adme"`

    - `cost_per_unit_usd: str`

      Estimated cost per displayed unit as a decimal string, rounded up to 4 decimal places. This may include token-size multipliers or generation overhead; estimated_cost_usd is the authoritative total.

    - `num_units: int`

      Number of units shown for the estimate. For structure-and-binding, this is the requested number of samples. For protein and small-molecule design/screen endpoints, this is the requested number of proteins or molecules.

  - `disclaimer: str`

  - `estimated_cost_usd: str`

    Estimated total cost as a decimal string

### Example

```python
import os
from boltz_api import Boltz

client = Boltz(
    api_key=os.environ.get("BOLTZ_API_KEY"),  # This is the default and can be omitted
)
response = client.small_molecule.library_screen.estimate_cost(
    molecules=[{
        "smiles": "smiles"
    }],
    target={
        "entities": [{
            "chain_ids": ["string"],
            "type": "protein",
            "value": "value",
        }]
    },
)
print(response.breakdown)
```