diff --git a/.gitignore b/.gitignore
index e6a5d69e27..2ef07dacbc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -42,6 +42,9 @@ share/python-wheels/
 *.egg
 MANIFEST
 
+# Poetry requirements / packaging
+/pyproject.toml
+
 # PyInstaller
 #  Usually these files are written by a python script from a template
 #  before PyInstaller builds the exe, so as to inject date/other infos into it.
diff --git a/src/schema/SCHEMA_VERSION b/src/schema/SCHEMA_VERSION
index 1351681fa7..4259c642a3 100644
--- a/src/schema/SCHEMA_VERSION
+++ b/src/schema/SCHEMA_VERSION
@@ -1 +1 @@
-0.4.1-dev
+0.5.0-dev
diff --git a/src/schema/meta/context.yaml b/src/schema/meta/context.yaml
index 4f7da046b3..3bdefaf873 100644
--- a/src/schema/meta/context.yaml
+++ b/src/schema/meta/context.yaml
@@ -20,6 +20,9 @@
 context:
   type: object
   properties:
+    schema:
+      description: 'The BIDS specification schema'
+      type: object
     dataset:
       description: 'Properties and contents of the entire dataset'
       type: object
@@ -36,6 +39,9 @@ context:
         ignored:
           description: 'Set of ignored files'
           type: array
+        datatypes:
+          description: 'Data types present in the dataset'
+          type: array
         modalities:
           description: 'Modalities present in the dataset'
           type: array
diff --git a/src/schema/objects/entities.yaml b/src/schema/objects/entities.yaml
index 5349e4b96a..4ac5909197 100644
--- a/src/schema/objects/entities.yaml
+++ b/src/schema/objects/entities.yaml
@@ -7,21 +7,21 @@ acquisition:
   name: acq
   display_name: Acquisition
   description: |
-    The `acq-<label>` entity corresponds to a custom label the
-    user MAY use to distinguish a different set of parameters used for
-    acquiring the same modality.
-    For example this should be used when a study includes two T1w images - one
-    full brain low resolution and one restricted field of view but high
-    resolution.
+    The `acq-<label>` entity corresponds to a custom label the user MAY use to distinguish
+    a different set of parameters used for acquiring the same modality.
+
+    For example, this should be used when a study includes two T1w images -
+    one full brain low resolution and one restricted field of view but high resolution.
     In such case two files could have the following names:
-    `sub-01_acq-highres_T1w.nii.gz` and `sub-01_acq-lowres_T1w.nii.gz`, however
-    the user is free to choose any other label than `highres` and `lowres` as long
+    `sub-01_acq-highres_T1w.nii.gz` and `sub-01_acq-lowres_T1w.nii.gz`;
+    however, the user is free to choose any other label than `highres` and `lowres` as long
     as they are consistent across subjects and sessions.
+
     In case different sequences are used to record the same modality
     (for example, `RARE` and `FLASH` for T1w)
     this field can also be used to make that distinction.
-    At what level of detail to make the distinction (for example,
-    just between `RARE` and `FLASH`, or between `RARE`, `FLASH`, and `FLASHsubsampled`)
+    The level of detail at which the distinction is made
+    (for example, just between `RARE` and `FLASH`, or between `RARE`, `FLASH`, and `FLASHsubsampled`)
     remains at the discretion of the researcher.
   type: string
   format: label
@@ -39,20 +39,21 @@ ceagent:
   name: ce
   display_name: Contrast Enhancing Agent
   description: |
-    The `ce-<label>` entity can be used to distinguish
-    sequences using different contrast enhanced images.
+    The `ce-<label>` entity can be used to distinguish sequences using different contrast enhanced images.
     The label is the name of the contrast agent.
-    The key `"ContrastBolusIngredient"` MAY also be added in the JSON file,
-    with the same label.
+
+    This entity represents the `"ContrastBolusIngredient"` metadata field.
+    Therefore, if the `ce-<label>` entity is present in a filename,
+    `"ContrastBolusIngredient"` MAY also be added in the JSON file, with the same label.
   type: string
   format: label
 chunk:
   name: chunk
   display_name: Chunk
   description: |
-    The `chunk-<index>` key/value pair is used to distinguish between different
-    regions, 2D images or 3D volumes files, of the same physical sample with
-    different fields of view acquired in the same imaging experiment.
+    The `chunk-<index>` key/value pair is used to distinguish between different regions,
+    2D images or 3D volumes files,
+    of the same physical sample with different fields of view acquired in the same imaging experiment.
   type: string
   format: index
 density:
@@ -60,8 +61,10 @@ density:
   display_name: Density
   description: |
     Density of non-parametric surfaces.
-    MUST have a corresponding `Density` metadata field to provide
-    interpretation.
+
+    This entity represents the `"Density"` metadata field.
+    Therefore, if the `den-<label>` entity is present in a filename,
+    `"Density"` MUST also be added in the JSON file, to provide interpretation.
 
     This entity is only applicable to derivative data.
   type: string
@@ -71,7 +74,7 @@ description:
   display_name: Description
   description: |
     When necessary to distinguish two files that do not otherwise have a
-    distinguishing entity, the `_desc-<label>` entity SHOULD be used.
+    distinguishing entity, the `desc-<label>` entity SHOULD be used.
 
     This entity is only applicable to derivative data.
   type: string
@@ -81,8 +84,13 @@ direction:
   display_name: Phase-Encoding Direction
   description: |
     The `dir-<label>` entity can be set to an arbitrary alphanumeric label
-    (for example, `dir-LR` or `dir-AP`) to distinguish different phase-encoding
-    directions.
+    (for example, `dir-LR` or `dir-AP`)
+    to distinguish different phase-encoding directions.
+
+    This entity represents the `"PhaseEncodingDirection"` metadata field.
+    Therefore, if the `dir-<label>` entity is present in a filename,
+    `"PhaseEncodingDirection"` MUST be defined in the associated metadata.
+    Please note that the `<label>` does not need to match the actual value of the field.
   type: string
   format: label
 echo:
@@ -90,12 +98,13 @@ echo:
   display_name: Echo
   description: |
     If files belonging to an entity-linked file collection are acquired at different
-    echo times, the `_echo-<index>` entity MUST be used to distinguish
-    individual files.
-    This entity represents the `"EchoTime"` metadata field. Please note that the `<index>`
-    denotes the number/index (in the form of a nonnegative integer), not the
-    `"EchoTime"` value which needs to be stored in the field `"EchoTime"` of the separate
-    JSON file.
+    echo times, the `echo-<index>` entity MUST be used to distinguish individual files.
+
+    This entity represents the `"EchoTime"` metadata field.
+    Therefore, if the `echo-<index>` entity is present in a filename,
+    `"EchoTime"` MUST be defined in the associated metadata.
+    Please note that the `<index>` denotes the number/index (in the form of a nonnegative integer),
+    not the `"EchoTime"` value of the separate JSON file.
   type: string
   format: index
 flip:
@@ -105,9 +114,12 @@ flip:
     If files belonging to an entity-linked file collection are acquired at different
     flip angles, the `_flip-<index>` entity pair MUST be used to distinguish
     individual files.
-    This entity represents the `"FlipAngle"` metadata field. Please note that the `<index>`
-    denotes the number/index (in the form of a nonnegative integer), not the `"FlipAngle"`
-    value which needs to be stored in the field `"FlipAngle"` of the separate JSON file.
+
+    This entity represents the `"FlipAngle"` metadata field.
+    Therefore, if the `flip-<index>` entity is present in a filename,
+    `"FlipAngle"` MUST be defined in the associated metadata.
+    Please note that the `<index>` denotes the number/index (in the form of a nonnegative integer),
+    not the `"FlipAngle"` value of the separate JSON file.
   type: string
   format: index
 hemisphere:
@@ -126,12 +138,14 @@ inversion:
   name: inv
   display_name: Inversion Time
   description: |
-    If files belonging to an entity-linked file collection are acquired at different
-    inversion times, the `_inv-<index>` entity MUST be used to distinguish
-    individual files.
-    This entity represents the `"InversionTime` metadata field. Please note that the `<index>`
-    denotes the number/index (in the form of a nonnegative integer), not the `"InversionTime"`
-    value which needs to be stored in the field `"InversionTime"` of the separate JSON file.
+    If files belonging to an entity-linked file collection are acquired at different inversion times,
+    the `inv-<index>` entity MUST be used to distinguish individual files.
+
+    This entity represents the `"InversionTime` metadata field.
+    Therefore, if the `inv-<index>` entity is present in a filename,
+    `"InversionTime"` MUST be defined in the associated metadata.
+    Please note that the `<index>` denotes the number/index (in the form of a nonnegative integer),
+    not the `"InversionTime"` value of the separate JSON file.
   type: string
   format: index
 label:
@@ -161,9 +175,12 @@ mtransfer:
     If files belonging to an entity-linked file collection are acquired at different
     magnetization transfer (MT) states, the `_mt-<label>` entity MUST be used to
     distinguish individual files.
-    This entity represents the `"MTState"` metadata field. Allowed label values for this
-    entity are `on` and `off`, for images acquired in presence and absence of an MT pulse,
-    respectively.
+
+    This entity represents the `"MTState"` metadata field.
+    Therefore, if the `mt-<label>` entity is present in a filename,
+    `"MTState"` MUST be defined in the associated metadata.
+    Allowed label values for this entity are `on` and `off`,
+    for images acquired in presence and absence of an MT pulse, respectively.
   type: string
   enum:
     - 'on'
@@ -210,19 +227,19 @@ reconstruction:
   name: rec
   display_name: Reconstruction
   description: |
-    The `rec-<label>` entity can be used to distinguish
-    different reconstruction algorithms (for example `MoCo` for the ones using motion
-    correction).
+    The `rec-<label>` entity can be used to distinguish different reconstruction algorithms
+    (for example, `MoCo` for the ones using motion correction).
   type: string
   format: label
 recording:
   name: recording
   display_name: Recording
   description: |
-    More than one continuous recording file can be included (with different
-    sampling frequencies).
-    In such case use different labels.
-    For example: `_recording-contrast`, `_recording-saturation`.
+    The `recording-<label>` entity can be used to distinguish continuous recording files.
+
+    This entity is commonly applied when continuous recordings have different sampling frequencies or start times.
+    For example, physiological recordings with different sampling frequencies may be distinguished using
+    labels like `recording-100Hz` and `recording-500Hz`.
   type: string
   format: label
 resolution:
@@ -230,8 +247,10 @@ resolution:
   display_name: Resolution
   description: |
     Resolution of regularly sampled N-dimensional data.
-    MUST have a corresponding `"Resolution"` metadata field to provide
-    interpretation.
+
+    This entity represents the `"Resolution"` metadata field.
+    Therefore, if the `res-<label>` entity is present in a filename,
+    `"Resolution"` MUST also be added in the JSON file, to provide interpretation.
 
     This entity is only applicable to derivative data.
   type: string
@@ -240,11 +259,14 @@ run:
   name: run
   display_name: Run
   description: |
+    The `run-<index>` entity is used to distinguish separate data acquisitions with the same acquisition parameters
+    and (other) entities.
+
     If several data acquisitions (for example, MRI scans or EEG recordings)
     with the same acquisition parameters are acquired in the same session,
     they MUST be indexed with the [`run-<index>`](../99-appendices/09-entities.md#run) entity:
-    `_run-1`, `_run-2`, `_run-3`, and so on (only nonnegative integers are allowed as
-    run labels).
+    `_run-1`, `_run-2`, `_run-3`, and so on
+    (only nonnegative integers are allowed as run indices).
 
     If different entities apply,
     such as a different session indicated by [`ses-<label>`](../99-appendices/09-entities.md#ses),
@@ -257,22 +279,17 @@ sample:
   name: sample
   display_name: Sample
   description: |
-    A sample pertaining to a subject such as tissue, primary cell
-    or cell-free sample.
-    The `sample-<label>` entity is used to distinguish between different
-    samples from the same subject.
-    The label MUST be unique per subject and is RECOMMENDED to be unique
-    throughout the dataset.
+    A sample pertaining to a subject such as tissue, primary cell or cell-free sample.
+    The `sample-<label>` entity is used to distinguish between different samples from the same subject.
+    The label MUST be unique per subject and is RECOMMENDED to be unique throughout the dataset.
   type: string
   format: label
 session:
   name: ses
   display_name: Session
   description: |
-    A logical grouping of neuroimaging and behavioral data consistent across
-    subjects.
-    Session can (but doesn't have to) be synonymous to a visit in a
-    longitudinal study.
+    A logical grouping of neuroimaging and behavioral data consistent across subjects.
+    Session can (but doesn't have to) be synonymous to a visit in a longitudinal study.
     In general, subjects will stay in the scanner during one session.
     However, for example, if a subject has to leave the scanner room and then
     be re-positioned on the scanner bed, the set of MRI acquisitions will still
@@ -280,6 +297,7 @@ session:
     Similarly, in situations where different data types are obtained over
     several visits (for example fMRI on one day followed by DWI the day after)
     those can be grouped in one session.
+
     Defining multiple sessions is appropriate when several identical or similar
     data acquisitions are planned and performed on all -or most- subjects,
     often in the case of some intervention between sessions
@@ -290,40 +308,37 @@ space:
   name: space
   display_name: Space
   description: |
-    The space entity can be used to indicate
-    the way in which electrode positions are interpreted
-    (for EEG/MEG/iEEG data) or
-    the spatial reference to which a file has been aligned (for MRI data).
-    The space `<label>` MUST be taken from one of the modality specific lists in
+    The `space-<label>` entity can be used to indicate the way in which electrode positions are interpreted
+    (for EEG/MEG/iEEG data)
+    or the spatial reference to which a file has been aligned (for MRI data).
+    The `<label>` MUST be taken from one of the modality specific lists in
     [Appendix VIII](../99-appendices/08-coordinate-systems.md).
-    For example for iEEG data, the restricted keywords listed under
-    [iEEG Specific Coordinate Systems](../99-appendices/08-coordinate-systems.md#ieeg-specific-coordinate-systems)
+    For example, for iEEG data, the restricted keywords listed under
+    [iEEG-Specific Coordinate Systems](../99-appendices/08-coordinate-systems.md#ieeg-specific-coordinate-systems)
     are acceptable for `<label>`.
 
-    For EEG/MEG/iEEG data, this entity can be applied to raw data, but
-    for other data types, it is restricted to derivative data.
+    For EEG/MEG/iEEG data, this entity can be applied to raw data,
+    but for other data types, it is restricted to derivative data.
   type: string
   format: label
 split:
   name: split
   display_name: Split
   description: |
-    In the case of long data recordings that exceed a file size of 2Gb, the
-    .fif files are conventionally split into multiple parts.
+    In the case of long data recordings that exceed a file size of 2Gb,
+    `.fif` files are conventionally split into multiple parts.
     Each of these files has an internal pointer to the next file.
-    This is important when renaming these split recordings to the BIDS
-    convention.
+    This is important when renaming these split recordings to the BIDS convention.
 
     Instead of a simple renaming, files should be read in and saved under their
     new names with dedicated tools like [MNE-Python](https://mne.tools/),
-    which will ensure that not only the file names, but also the internal file
-    pointers will be updated.
-    It is RECOMMENDED that .fif files with multiple parts use the
-    `split-<index>` entity to indicate each part.
+    which will ensure that not only the file names, but also the internal file pointers, will be updated.
+
+    It is RECOMMENDED that `.fif` files with multiple parts use the `split-<index>` entity to indicate each part.
     If there are multiple parts of a recording and the optional `scans.tsv` is provided,
-    remember to list all files separately in `scans.tsv` and that the entries for the
-    `acq_time` column in `scans.tsv` MUST all be identical, as described in
-    [Scans file](../03-modality-agnostic-files.md#scans-file).
+    all files MUST be listed separately in `scans.tsv` and
+    the entries for the `acq_time` column in `scans.tsv` MUST all be identical,
+    as described in [Scans file](../03-modality-agnostic-files.md#scans-file).
   type: string
   format: index
 stain:
@@ -332,10 +347,14 @@ stain:
   description: |
     The `stain-<label>` key/pair values can be used to distinguish image files
     from the same sample using different stains or antibodies for contrast enhancement.
-    Stains SHOULD be indicated in the `"SampleStaining"` key in the sidecar JSON file,
+
+    This entity represents the `"SampleStaining"` metadata field.
+    Therefore, if the `stain-<label>` entity is present in a filename,
+    `"SampleStaining"` SHOULD be defined in the associated metadata,
     although the label may be different.
-    Description of antibodies SHOULD also be indicated in `"SamplePrimaryAntibodies"`
-    and/or `"SampleSecondaryAntobodies"` as appropriate.
+
+    Descriptions of antibodies SHOULD also be indicated in the `"SamplePrimaryAntibodies"`
+    and/or `"SampleSecondaryAntobodies"` metadata fields, as appropriate.
   type: string
   format: label
 subject:
@@ -351,29 +370,36 @@ task:
   description: |
     A set of structured activities performed by the participant.
     Tasks are usually accompanied by stimuli and responses, and can greatly vary in complexity.
-    For the purpose of this specification we consider the so-called "resting state" a task,
-    although events files are not expected for resting state data.
-    Additionally, a common convention in the specification is to include the word "rest" in
-    the `task` label for resting state files (for example, `task-rest`).
 
     In the context of brain scanning, a task is always tied to one data acquisition.
     Therefore, even if during one acquisition the subject performed multiple conceptually different behaviors
     (with different sets of instructions) they will be considered one (combined) task.
+
+    While tasks may be repeated across multiple acquisitions,
+    a given task may have different sets of stimuli (for example, randomized order) and participant responses
+    across subjects, sessions, and runs.
+
     The `task-<label>` MUST be consistent across subjects and sessions.
 
     Files with the `task-<label>` entity SHOULD have an associated
     [events file](SPEC_ROOT/04-modality-specific-files/05-task-events.md#task-events),
     as well as certain metadata fields in the associated JSON file.
 
+    For the purpose of this specification we consider the so-called "resting state" a task,
+    although events files are not expected for resting state data.
+    Additionally, a common convention in the specification is to include the word "rest" in
+    the `task` label for resting state files (for example, `task-rest`).
   type: string
   format: label
 tracer:
   name: trc
   display_name: Tracer
   description: |
-    The `trc-<label>` entity can be used to distinguish
-    sequences using different tracers.
-    The key `"TracerName"` MUST also be included in the associated JSON file,
-    although the label may be different.
+    The `trc-<label>` entity can be used to distinguish sequences using different tracers.
+
+    This entity represents the `"TracerName"` metadata field.
+    Therefore, if the `trc-<label>` entity is present in a filename,
+    `"TracerName"` MUST be defined in the associated metadata.
+    Please note that the `<label>` does not need to match the actual value of the field.
   type: string
   format: label
diff --git a/src/schema/rules/checks/asl.yaml b/src/schema/rules/checks/asl.yaml
index 59641f6628..b2415796c2 100644
--- a/src/schema/rules/checks/asl.yaml
+++ b/src/schema/rules/checks/asl.yaml
@@ -22,7 +22,7 @@ ASLLabelingDurationNiftiLength:
     - '"LabelingDuration" in sidecar'
     - type(sidecar.LabelingDuration) == 'array'
   checks:
-    - nifti_header.dim[4] == sidecar.LabelingDuration.length
+    - length(sidecar.LabelingDuration) == nifti_header.dim[4]
 
 # 165
 ASLContextConsistent:
@@ -57,7 +57,7 @@ ASLFlipAngleNiftiLength:
     - '"FlipAngle" in sidecar'
     - type(sidecar.FlipAngle) == 'array'
   checks:
-    - nifti_header.dim[4] == sidecar.FlipAngle.length
+    - length(sidecar.FlipAngle) == nifti_header.dim[4]
 
 # 172
 ASLFlipAngleASLContextLength:
@@ -79,7 +79,7 @@ ASLFlipAngleASLContextLength:
     - '"FlipAngle" in sidecar'
     - type(sidecar.FlipAngle) == 'array'
   checks:
-    - aslcontext.n_rows == sidecar.FlipAngle.length
+    - length(sidecar.FlipAngle) == aslcontext.n_rows
 
 # 173
 ASLPostLabelingDelayNiftiLength:
@@ -103,7 +103,7 @@ ASLPostLabelingDelayNiftiLength:
     - '"aslcontext" in associations'
     - type(sidecar.PostLabelingDelay) == 'array'
   checks:
-    - nifti_header.pixdim[4] == sidecar.PostLabelingDelay.length
+    - length(sidecar.PostLabelingDelay) == nifti_header.dim[4]
 
 # 174
 ASLPostLabelingDelayASLContextLength:
@@ -127,7 +127,7 @@ ASLPostLabelingDelayASLContextLength:
     - '"aslcontext" in associations'
     - type(sidecar.PostLabelingDelay) == 'array'
   checks:
-    - aslcontext.n_rows == sidecar.PostLabelingDelay.length
+    - length(sidecar.PostLabelingDelay) == aslcontext.n_rows
 
 # 175
 ASLLabelingDurationASLContextLength:
@@ -153,7 +153,7 @@ ASLLabelingDurationASLContextLength:
     - '"LabelingDuration" in sidecar'
     - type(sidecar.LabelingDuration) == 'array'
   checks:
-    - aslcontext.n_rows == sidecar.LabelingDuration.length
+    - length(sidecar.LabelingDuration) == aslcontext.n_rows
 
 # 177
 ASLRepetitionTimePreparationASLContextLength:
@@ -174,7 +174,7 @@ ASLRepetitionTimePreparationASLContextLength:
     - '"RepetitionTimePreparation" in sidecar'
     - type(sidecar.RepetitionTimePreparation) == 'array'
   checks:
-    - aslcontext.n_rows == sidecar.RepetitionTimePreparation.length
+    - length(sidecar.RepetitionTimePreparation) == aslcontext.n_rows
 
 # 180
 ASLBackgroundSuppressionNumberPulses:
@@ -192,7 +192,7 @@ ASLBackgroundSuppressionNumberPulses:
     - '"BackgroundSuppressionPulseTime" in sidecar'
     - type(sidecar.BackgroundSuppressionPulseTime) == 'array'
   checks:
-    - sidecar.BackgroundSuppressionPulseTime.length == sidecar.BackgroundSuppressionNumberPulses
+    - length(sidecar.BackgroundSuppressionPulseTime) == sidecar.BackgroundSuppressionNumberPulses
 
 # 181
 ASLTotalAcquiredVolumesASLContextLength:
@@ -226,7 +226,7 @@ ASLEchoTimeASLContextLength:
     - '"EchoTime" in sidecar'
     - type(sidecar.EchoTime) == 'array'
   checks:
-    - aslcontext.n_rows == sidecar.EchoTime.length
+    - length(sidecar.EchoTime) == aslcontext.n_rows
 
 # 198
 ASLM0TypeAbsentScan:
@@ -256,7 +256,7 @@ ASLM0TypeAbsentASLContext:
   selectors:
     - suffix == "asl"
     - '"aslcontext" in associations'
-    - aslcontext.volume_type.includes('"m0scan")
+    - intersects(aslcontext.volume_type, ["m0scan"])
     - '"M0Type" in sidecar'
   checks:
     - sidecar.M0Type != "absent"
diff --git a/src/schema/rules/checks/dwi.yaml b/src/schema/rules/checks/dwi.yaml
index 98ed898d3a..d5d00b6a5c 100644
--- a/src/schema/rules/checks/dwi.yaml
+++ b/src/schema/rules/checks/dwi.yaml
@@ -2,11 +2,12 @@
 ---
 # 29
 DWIVolumeCount:
-  code: VOLUME_COUNT_MISMATCH
-  description: |
-    The number of volumes in this scan does not match the number of volumes in the
-    corresponding .bvec and .bval files.
-  level: error
+  issue:
+    code: VOLUME_COUNT_MISMATCH
+    message: |
+      The number of volumes in this scan does not match the number of volumes in the
+      corresponding .bvec and .bval files.
+    level: error
   selectors:
     - suffix == "dwi"
     - '"bval" in associations'
@@ -17,10 +18,11 @@ DWIVolumeCount:
 
 # 30
 DWIBvalRows:
-  code: BVAL_MULTIPLE_ROWS
-  description: |
-    '.bval' files should contain exactly one row of volumes.
-  level: error
+  issue:
+    code: BVAL_MULTIPLE_ROWS
+    message: |
+      '.bval' files should contain exactly one row of volumes.
+    level: error
   selectors:
     - extension == "bval"
   checks:
@@ -28,10 +30,11 @@ DWIBvalRows:
 
 # 31
 DWIBvecRows:
-  code: BVEC_NUMBER_ROWS
-  description: |
-    '.bvec' files should contain exactly three rows of volumes.
-  level: error
+  issue:
+    code: BVEC_NUMBER_ROWS
+    message: |
+      '.bvec' files should contain exactly three rows of volumes.
+    level: error
   selectors:
     - extension == "bvec"
   checks:
@@ -39,10 +42,11 @@ DWIBvecRows:
 
 # 32
 DWIMissingBvec:
-  code: DWI_MISSING_BVEC
-  description: |
-    DWI scans must have a corresponding .bvec file.
-  level: error
+  issue:
+    code: DWI_MISSING_BVEC
+    message: |
+      DWI scans must have a corresponding .bvec file.
+    level: error
   selectors:
     - suffix == "dwi"
   checks:
@@ -50,10 +54,11 @@ DWIMissingBvec:
 
 # 33
 DWIMissingBval:
-  code: DWI_MISSING_BVAL
-  description: |
-    DWI scans must have a corresponding .bval file.
-  level: error
+  issue:
+    code: DWI_MISSING_BVAL
+    message: |
+      DWI scans must have a corresponding .bval file.
+    level: error
   selectors:
     - suffix == "dwi"
   checks:
diff --git a/src/schema/rules/checks/events.yaml b/src/schema/rules/checks/events.yaml
index 76650acd48..fae94b41a3 100644
--- a/src/schema/rules/checks/events.yaml
+++ b/src/schema/rules/checks/events.yaml
@@ -10,7 +10,7 @@ EventsMissing:
     level: warning # could be an error with the proper selectors, I think
   selectors:
     - '"task" in entities'
-    - '!(entities.task.includes("rest"))'
+    - '!matches(entities.task, "rest")'
     - suffix != "events"
   checks:
     - '"events" in associations'
diff --git a/src/schema/rules/checks/func.yaml b/src/schema/rules/checks/func.yaml
index 070c5b7244..980444dc02 100644
--- a/src/schema/rules/checks/func.yaml
+++ b/src/schema/rules/checks/func.yaml
@@ -13,4 +13,4 @@ PhaseSuffixDeprecated:
   selectors:
     - datatype == "func"
   checks:
-    - '!(suffix == "phase")'
+    - suffix != "phase"
diff --git a/src/schema/rules/checks/mri.yaml b/src/schema/rules/checks/mri.yaml
new file mode 100644
index 0000000000..4fd76f1716
--- /dev/null
+++ b/src/schema/rules/checks/mri.yaml
@@ -0,0 +1,14 @@
+---
+PhasePartUnits:
+  issue:
+    code: PHASE_UNITS
+    message: |
+      Phase images (with the `part-phase` entity) must have units
+      "rad" or "arbitrary".
+    level: error
+  selectors:
+    - modality == "mri"
+    - entities.part == "phase"
+    - '"Units" in sidecar'
+  checks:
+    - intersects([sidecar.Units], ["rad", "arbitrary"])
diff --git a/src/schema/rules/common_derivatives_validation.yaml b/src/schema/rules/common_derivatives_validation.yaml
index e4f32125fc..723ddf0e59 100644
--- a/src/schema/rules/common_derivatives_validation.yaml
+++ b/src/schema/rules/common_derivatives_validation.yaml
@@ -2,8 +2,8 @@
 ResInSidecar:
   selectors:
     - dataset.dataset_description.DatasetType == "derivative"
-    - '["mri", "pet"].includes(modality)'
-    - '["nii", " nii.gz"].includes(extension)'
+    - intersects([modality], ["mri", "pet"])
+    - match(extension, '^\.nii(\.gz)?$')
     - type(sidecar.Resolution) == "object"
   checks:
     - entities.resolution in sidecar.Resolution
@@ -11,8 +11,8 @@ ResInSidecar:
 DenInSidecar:
   selectors:
     - dataset.dataset_description.DatasetType == "derivative"
-    - '["mri", "pet"].includes(modality)'
-    - '[".nii", ".nii.gz"].includes(extension)'
+    - intersects([modality], ["mri", "pet"])
+    - match(extension, '^\.nii(\.gz)?$')
     - type(sidecar.Density) == "object"
   checks:
     - entities.density in sidecar.Density
diff --git a/src/schema/rules/dataset_metadata.yaml b/src/schema/rules/dataset_metadata.yaml
index 145928309e..29466a80eb 100644
--- a/src/schema/rules/dataset_metadata.yaml
+++ b/src/schema/rules/dataset_metadata.yaml
@@ -42,7 +42,7 @@ derivative_description:
 dataset_description_with_genetics:
   selectors:
     - path == "/dataset_description.json"
-    - 'dataset.files.includes("/genetic_info.json")'
+    - intersects(dataset.files, ["/genetic_info.json"])
   fields:
     Genetics: required
     Genetics{}.Dataset:
diff --git a/src/schema/rules/errors.yaml b/src/schema/rules/errors.yaml
index b9d65729bd..0a41808075 100644
--- a/src/schema/rules/errors.yaml
+++ b/src/schema/rules/errors.yaml
@@ -9,7 +9,7 @@ NiftiHeaderUnreadable:
     Please ensure it is not corrupted or mislabeled.
   level: error
   selectors:
-    - '[".nii", ".nii.gz"].includes(extension)'
+    - match(extension, '^\.nii(\.gz)?$')
 
 # BIDS Validator Original Issue Code #27
 JsonInvalid:
@@ -27,7 +27,7 @@ GzNotGzipped:
     This file ends in the .gz extension but is not actually gzipped.
   level: error
   selectors:
-    - extension.includes(".gz")
+    - match(extension, '\.gz$')
 
 # BIDS Validator Original Issue Code #30
 BvalMultipleRows:
@@ -54,7 +54,7 @@ NiftiTooSmall:
     This file is too small to contain the minimal NIfTI header.
   level: error
   selectors:
-    - '[".nii", ".nii.gz"].includes(extension)'
+    - match(extension, '^\.nii(\.gz)?$')
 
 # BIDS Validator Original Issue Code #43
 OrphanedSymlink:
@@ -90,7 +90,7 @@ BFile:
     and contain only numerical values.
   level: error
   selectors:
-    - '[".bval", ".bvec"].includes(extension)'
+    - intersects([extension], [".bval", ".bvec"])
 
 # BIDS Validator Original Issue Code #55
 JsonSchemaValidationError:
@@ -175,7 +175,7 @@ BrainvisionLinksBroken:
     and *.vmrk) are broken or some files do not exist.
   level: error
   selectors:
-    - '[ ".eeg", ".vhdr", ".vmrk"].includes(extension)'
+    - intersects([extension], [".eeg", ".vhdr", ".vmrk"])
 
 # BIDS Validator Original Issue Code #104
 HedError:
diff --git a/src/schema/rules/sidecars/anat.yaml b/src/schema/rules/sidecars/anat.yaml
index 62231f8f07..61958ef461 100644
--- a/src/schema/rules/sidecars/anat.yaml
+++ b/src/schema/rules/sidecars/anat.yaml
@@ -9,7 +9,7 @@
 
 MRIAnatomyCommonMetadataFields:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "anat"
   fields:
     ContrastBolusIngredient: optional
@@ -18,7 +18,7 @@ MRIAnatomyCommonMetadataFields:
 
 PhaseEntityUnits:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "anat"
     - entities.part == "phase"
   fields:
@@ -26,7 +26,7 @@ PhaseEntityUnits:
 
 PhaseSuffixUnits:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "anat"
     - suffix == "phase"
   fields:
diff --git a/src/schema/rules/sidecars/asl.yaml b/src/schema/rules/sidecars/asl.yaml
index 5c8b9d97d8..f0b91e10d4 100644
--- a/src/schema/rules/sidecars/asl.yaml
+++ b/src/schema/rules/sidecars/asl.yaml
@@ -8,91 +8,16 @@
 # Fields described in text, but not in tables
 MRIASLTextOnly:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
-    - suffix == "asl"
+    - intersects([suffix], ["asl", "m0scan"])
   fields:
-    MagneticFieldStrength: required
-    MRAcquisitionType: required
-    EchoTime: required
     RepetitionTimePreparation: required
 
-MRIASLTextOnlySliceTimingRec:
-  selectors:
-    - modality == "MRI"
-    - datatype == "perf"
-    - suffix == "asl"
-    - sidecar.MRAcquisitionType != "2D"
-  fields:
-    SliceTiming:
-      level: recommended
-      level_addendum: required if `MRAcquisitionType` is defined as `2D`
-
-MRIASLTextOnlySliceTimingReq:
-  selectors:
-    - modality == "MRI"
-    - datatype == "perf"
-    - suffix == "asl"
-    - sidecar.MRAcquisitionType == "2D"
-  fields:
-    SliceTiming:
-      level: required
-      issue:
-        code: SLICE_TIMING_NOT_DEFINED_2D_ASL
-        message: |
-          You should define `SliceTiming` for this file, because `SequenceType` is sets
-          to a 2D sequence. `SliceTiming` is the time at which each slice was
-          acquired within each volume (frame) of the acquisition. Slice timing
-          is not slice order -- rather, it is a list of times containing the
-          time (in seconds) of each slice acquisition in relation to the beginning
-          of volume acquisition. The list goes through the slices along the slice
-          axis in the slice encoding dimension (see below). Note that to ensure the
-          proper interpretation of the `SliceTiming` field, it is important to check
-          if the optional `SliceEncodingDirection` exists. In particular, if
-          `SliceEncodingDirection` is negative, the entries in `SliceTiming` are
-          defined in reverse order with respect to the slice axis, such that the
-          final entry in the `SliceTiming` list is the time of acquisition of slice 0.
-          Without this parameter slice time correction will not be possible.
-
-MRIASLTextOnlyFlipAngleRec:
-  selectors:
-    - modality == "MRI"
-    - datatype == "perf"
-    - suffix == "asl"
-    - '!(LookLocker in sidecar) || sidecar.LookLocker == false'
-  fields:
-    FlipAngle:
-      level: recommended
-      level_addendum: required if `LookLocker` is `true`
-
-MRIASLTextOnlyFlipAngleReq:
-  selectors:
-    - modality == "MRI"
-    - datatype == "perf"
-    - suffix == "asl"
-    - sidecar.LookLocker == true
-  fields:
-    FlipAngle:
-      level: required
-      issue:
-        code: LOOK_LOCKER_FLIP_ANGLE_MISSING
-        message: |
-          You should define `FlipAngle` for this file, in case of a
-          LookLocker acquisition. `FlipAngle` is the flip angle (FA)
-          for the acquisition, specified in degrees. Corresponds to
-          DICOM Tag 0018, 1314 `Flip Angle`. The data type number may
-          apply to files from any MRI modality concerned with a single
-          value for this field, or to the files in a file collection
-          where the value of this field is iterated using the flip entity.
-          The data type array provides a value for each volume in a 4D
-          dataset and should only be used when the volume timing is critical
-          for interpretation of the data, such as in ASL or variable flip
-          angle fMRI sequences.
-
 # Common metadata fields applicable to both (P)CASL and PASL
 MRIASLCommonMetadataFields:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "asl"
   fields:
@@ -111,7 +36,7 @@ MRIASLCommonMetadataFields:
 
 MRIASLCommonMetadataFieldsM0TypeRec:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "asl"
     - sidecar.M0Type != "Estimate"
@@ -122,7 +47,7 @@ MRIASLCommonMetadataFieldsM0TypeRec:
 
 MRIASLCommonMetadataFieldsM0TypeReq:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "asl"
     - sidecar.M0Type == "Estimate"
@@ -139,7 +64,7 @@ MRIASLCommonMetadataFieldsM0TypeReq:
 
 MRIASLCommonMetadataFieldsBackgroundSuppressionOpt:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "asl"
     - sidecar.BackgroundSuppression == false
@@ -153,7 +78,7 @@ MRIASLCommonMetadataFieldsBackgroundSuppressionOpt:
 
 MRIASLCommonMetadataFieldsBackgroundSuppressionReq:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "asl"
     - sidecar.BackgroundSuppression == true
@@ -163,7 +88,7 @@ MRIASLCommonMetadataFieldsBackgroundSuppressionReq:
 
 MRIASLCommonMetadataFieldsVascularCrushingOpt:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "asl"
     - sidecar.VascularCrushing == false
@@ -174,7 +99,7 @@ MRIASLCommonMetadataFieldsVascularCrushingOpt:
 
 MRIASLCommonMetadataFieldsVascularCrushingRec:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "asl"
     - sidecar.VascularCrushing == true
@@ -183,10 +108,10 @@ MRIASLCommonMetadataFieldsVascularCrushingRec:
 
 MRIASLCaslPcaslSpecific:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "asl"
-    - '["CASL", "PCASL"].includes(sidecar.ArterialSpinLabelingType)'
+    - intersects([sidecar.ArterialSpinLabelingType], ["CASL", "PCASL"])
   fields:
     LabelingDuration: required
     LabelingPulseAverageGradient: recommended
@@ -198,7 +123,7 @@ MRIASLCaslPcaslSpecific:
 
 MRIASLPcaslSpecific:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "asl"
     - sidecar.ArterialSpinLabelingType == "PCASL"
@@ -209,7 +134,7 @@ MRIASLPcaslSpecific:
 
 MRIASLCaslSpecific:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "asl"
     - sidecar.ArterialSpinLabelingType == "CASL"
@@ -220,7 +145,7 @@ MRIASLCaslSpecific:
 
 MRIASLPaslSpecific:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "asl"
     - sidecar.ArterialSpinLabelingType == "PASL"
@@ -231,7 +156,7 @@ MRIASLPaslSpecific:
 
 MRIASLPASLSpecificBolusCutOffFlagFalse:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "asl"
     - sidecar.ArterialSpinLabelingType == "PASL"
@@ -246,7 +171,7 @@ MRIASLPASLSpecificBolusCutOffFlagFalse:
 
 MRIASLPaslSpecificBolusCutOffFlagTrue:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "asl"
     - sidecar.ArterialSpinLabelingType == "PASL"
@@ -278,51 +203,9 @@ MRIASLPaslSpecificBolusCutOffFlagTrue:
           Corresponds to DICOM Tag 0018,925E `ASL Bolus Cut-off Technique`.
 
 # m0scan metadata fields
-MRIASLM0ScanTextOnly:
-  selectors:
-    - modality == "MRI"
-    - datatype == "perf"
-    - suffix == "m0scan"
-  fields:
-    EchoTime: required
-    RepetitionTimePreparation: required
-
-MRIASLM0ScanTextOnlyFlipAngleRec:
-  selectors:
-    - modality == "MRI"
-    - datatype == "perf"
-    - suffix == "m0scan"
-    - '!(LookLocker in sidecar) || sidecar.LookLocker == false'
-  fields:
-    FlipAngle:
-      level: recommended
-      level_addendum: required if `LookLocker` is `true`
-
-MRIASLM0ScanTextOnlyFlipAngleReq:
-  selectors:
-    - modality == "MRI"
-    - datatype == "perf"
-    - suffix == "m0scan"
-    - sidecar.LookLocker == true
-  fields:
-    FlipAngle:
-      level: required
-      issue:
-        code: LOOK_LOCKER_FLIP_ANGLE_MISSING
-        message: |
-          You should define `FlipAngle` for this file, in case of a LookLocker
-          acquisition. `FlipAngle` is the flip angle (FA) for the acquisition,
-          specified in degrees. Corresponds to DICOM Tag 0018, 1314 `Flip Angle`.
-          The data type number may apply to files from any MRI modality concerned
-          with a single value for this field, or to the files in a file collection
-          where the value of this field is iterated using the flip entity. The
-          data type array provides a value for each volume in a 4D dataset and
-          should only be used when the volume timing is critical for interpretation
-          of the data, such as in ASL or variable flip angle fMRI sequences.
-
 MRIASLM0Scan:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "perf"
     - suffix == "m0scan"
   fields:
diff --git a/src/schema/rules/sidecars/beh.yaml b/src/schema/rules/sidecars/beh.yaml
index 91f14976ef..e9221986f6 100644
--- a/src/schema/rules/sidecars/beh.yaml
+++ b/src/schema/rules/sidecars/beh.yaml
@@ -8,7 +8,7 @@
 # Metadata for either beh or events files
 BEHTabularData:
   selectors:
-    - '["beh", "events"].includes(suffix)'
+    - intersects([suffix], ["beh", "events"])
   fields:
     TaskName: recommended
     Instructions: recommended
diff --git a/src/schema/rules/sidecars/continuous.yaml b/src/schema/rules/sidecars/continuous.yaml
index b96bdc7085..2e74912f4f 100644
--- a/src/schema/rules/sidecars/continuous.yaml
+++ b/src/schema/rules/sidecars/continuous.yaml
@@ -8,7 +8,7 @@
 # Metadata for either physio or stim files
 Continuous:
   selectors:
-    - '["physio", "stim"].includes(suffix)'
+    - intersects([suffix], ["physio", "stim"])
   fields:
     SamplingFrequency: required
     StartTime: required
diff --git a/src/schema/rules/sidecars/derivatives/common_derivatives.yaml b/src/schema/rules/sidecars/derivatives/common_derivatives.yaml
index 1d1c2e6fdd..f13d9620fa 100644
--- a/src/schema/rules/sidecars/derivatives/common_derivatives.yaml
+++ b/src/schema/rules/sidecars/derivatives/common_derivatives.yaml
@@ -1,7 +1,7 @@
 ---
 CommonDerivativeFields:
   selectors:
-    - dataset.DatasetType == "derivative"
+    - dataset.dataset_description.DatasetType == "derivative"
   fields:
     Description:
       level: recommended
@@ -11,7 +11,7 @@ CommonDerivativeFields:
 
 SpatialReferenceEntity:
   selectors:
-    - dataset.DatasetType == "derivative"
+    - dataset.dataset_description.DatasetType == "derivative"
     - '"space" in entities'
   fields:
     SpatialReference:
@@ -22,14 +22,14 @@ SpatialReferenceEntity:
 
 SpatialReferenceNonStandard:
   selectors:
-    - dataset.DatasetType == "derivative"
-    - '!(schema.objects.metadata._StandardTemplateCoordSys).includes(entities.space)'
+    - dataset.dataset_description.DatasetType == "derivative"
+    - '!intersects(schema.objects.metadata._StandardTemplateCoordSys, [entities.space])'
   fields:
     SpatialReference: required
 
 SpatialReferenceNoEntity:
   selectors:
-    - dataset.DatasetType == "derivative"
+    - dataset.dataset_description.DatasetType == "derivative"
     - '!("space" in entities)'
   fields:
     SpatialReference: required
@@ -38,7 +38,7 @@ SpatialReferenceNoEntity:
 # different way
 MaskDerivatives:
   selectors:
-    - dataset.DatasetType == "derivative"
+    - dataset.dataset_description.DatasetType == "derivative"
     - suffix == "mask"
   fields:
     Type: recommended
@@ -47,7 +47,7 @@ MaskDerivatives:
 
 MaskDerivativesAtlas:
   selectors:
-    - dataset.DatasetType == "derivative"
+    - dataset.dataset_description.DatasetType == "derivative"
     - suffix == "mask"
     - '"label" in entities'
   fields:
@@ -57,15 +57,15 @@ MaskDerivativesAtlas:
 
 SegmentationCommon:
   selectors:
-    - dataset.DatasetType == "derivative"
-    - '["dseg", "probseg"].includes(suffix)'
+    - dataset.dataset_description.DatasetType == "derivative"
+    - '!intersects([suffix], ["dseg", "probseg"])'
   fields:
     Manual: optional
 
 SegmentationCommonAtlas:
   selectors:
-    - dataset.DatasetType == "derivative"
-    - '["dseg", "probseg"].includes(suffix)'
+    - dataset.dataset_description.DatasetType == "derivative"
+    - '!intersects([suffix], ["dseg", "probseg"])'
     - '"atlas" in entities'
   fields:
     Atlas:
@@ -75,16 +75,16 @@ SegmentationCommonAtlas:
 # Derivatives -> Imaging data types
 ImageDerivatives:
   selectors:
-    - dataset.DatasetType == "derivative"
-    - '["mri", "pet"].includes(modality)'
-    - '[".nii", ".nii.gz"].includes(extension)'
+    - dataset.dataset_description.DatasetType == "derivative"
+    - '!intersects([modality], ["mri", "pet"])'
+    - '!match(extension, "^\.nii(\.gz)?$")'
   fields:
     SkullStripped: required
 
 ImageDerivativeResEntity:
   selectors:
-    - dataset.DatasetType == "derivative"
-    - '["mri", "pet"].includes(modality)'
+    - dataset.dataset_description.DatasetType == "derivative"
+    - '!intersects([modality], ["mri", "pet"])'
     - '"res" in entities'
   fields:
     Resolution:
@@ -93,8 +93,8 @@ ImageDerivativeResEntity:
 
 ImageDerivativeDenEntity:
   selectors:
-    - dataset.DatasetType == "derivative"
-    - '["mri", "pet"].includes(modality)'
+    - dataset.dataset_description.DatasetType == "derivative"
+    - '!intersects([modality], ["mri", "pet"])'
     - '"den" in entities'
   fields:
     Density:
diff --git a/src/schema/rules/sidecars/eeg.yaml b/src/schema/rules/sidecars/eeg.yaml
index deb0e2f18c..ecc13f7c13 100644
--- a/src/schema/rules/sidecars/eeg.yaml
+++ b/src/schema/rules/sidecars/eeg.yaml
@@ -133,7 +133,7 @@ EEGCoordsystemOtherFiducialCoordinateSystem:
     - modality == "eeg"
     - datatype == "eeg"
     - suffix == "coordsystem"
-    - FiducialsCoordinateSystem == "Other"
+    - sidecar.FiducialsCoordinateSystem == "Other"
   fields:
     FiducialsCoordinateSystemDescription: required
 
diff --git a/src/schema/rules/sidecars/entity_rules.yaml b/src/schema/rules/sidecars/entity_rules.yaml
index b7f86a3442..5b415d59a6 100644
--- a/src/schema/rules/sidecars/entity_rules.yaml
+++ b/src/schema/rules/sidecars/entity_rules.yaml
@@ -61,10 +61,7 @@ EntitiesPartMetadata:
   selectors:
     - entities.part == "phase"
   fields:
-    Units:
-      level: required
-      rules:
-        - '["rad", "arbitrary"].includes(value)'
+    Units: required
 
 EntitiesResMetadata:
   selectors:
diff --git a/src/schema/rules/sidecars/fmap.yaml b/src/schema/rules/sidecars/fmap.yaml
index 1b55095dfc..ddb90f3949 100644
--- a/src/schema/rules/sidecars/fmap.yaml
+++ b/src/schema/rules/sidecars/fmap.yaml
@@ -8,14 +8,14 @@
 # Fieldmap data
 MRIFieldmapB0FieldIdentifier:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "fmap"
   fields:
     B0FieldIdentifier: recommended
 
 MRIFieldmapIntendedFor:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "fmap"
   fields:
     IntendedFor:
@@ -27,7 +27,7 @@ MRIFieldmapIntendedFor:
 # Case 1: Phase-difference map and at least one magnitude image
 MRIFieldmapPhaseDifferencePhasediff:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "fmap"
     - suffix == "phasediff"
   fields:
@@ -36,7 +36,7 @@ MRIFieldmapPhaseDifferencePhasediff:
 
 MRIFieldmapPhaseDifferenceMagnitude1:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "fmap"
     - suffix == "magnitude1"
   fields:
@@ -44,7 +44,7 @@ MRIFieldmapPhaseDifferenceMagnitude1:
 
 MRIFieldmapPhaseDifferenceMagnitude2:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "fmap"
     - suffix == "magnitude2"
   fields:
@@ -56,18 +56,18 @@ MRIFieldmapPhaseDifferenceMagnitude2:
 # but EchoTime1 if phasediff exists.
 MRIFieldmapTwoPhase:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "fmap"
-    - '["phase1", "phase2", "magnitude1", "magnitude2"].includes(suffix)'
+    - intersects([suffix], ["phase1", "phase2", "magnitude1", "magnitude2"])
   fields:
     EchoTime__fmap: required
 
 # Case 3: Direct field mapping
 MRIFieldmapDirectFieldMapping:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "fmap"
-    - '["phase", "fieldmap"].includes(suffix)'
+    - intersects([suffix], ["phase", "fieldmap"])
   fields:
     Units:
       level: required
@@ -78,7 +78,7 @@ MRIFieldmapDirectFieldMapping:
 # Case 4: Multiple phase encoded directions ("pepolar")
 MRIFieldmapPepolar:
   selectors:
-    - modality == "MRI"
+    - modality == "mri"
     - datatype == "fmap"
     - suffix == "epi"
   fields:
diff --git a/src/schema/rules/sidecars/func.yaml b/src/schema/rules/sidecars/func.yaml
index fcfc8d6581..1c587f9549 100644
--- a/src/schema/rules/sidecars/func.yaml
+++ b/src/schema/rules/sidecars/func.yaml
@@ -12,7 +12,7 @@ MRIFuncRequired:
   selectors:
     - modality == "mri"
     - datatype == "func"
-    - '[".nii", ".nii.gz"].includes(extension)'
+    - match(extension, "^\.nii(\.gz)?$")
   fields:
     TaskName:
       level: required
@@ -25,7 +25,7 @@ MRIFuncRepetitionTime:
     - modality == "mri"
     - datatype == "func"
     - '!("VolumeTiming" in sidecar)'
-    - '[".nii", ".nii.gz"].includes(extension)'
+    - match(extension, "^\.nii(\.gz)?$")
   fields:
     RepetitionTime:
       level: required
@@ -36,7 +36,7 @@ MRIFuncVolumeTiming:
     - modality == "mri"
     - datatype == "func"
     - '!("RepetitionTime" in sidecar)'
-    - '[".nii", ".nii.gz"].includes(extension)'
+    - match(extension, "^\.nii(\.gz)?$")
   fields:
     VolumeTiming:
       level: required
diff --git a/src/schema/rules/sidecars/meg.yaml b/src/schema/rules/sidecars/meg.yaml
index f67e3c7b8f..b5d57e2f96 100644
--- a/src/schema/rules/sidecars/meg.yaml
+++ b/src/schema/rules/sidecars/meg.yaml
@@ -105,7 +105,7 @@ MEGwithEEG:
     - modality == "meg"
     - datatype == "meg"
     - suffix == "meg"
-    - dataset.modalities.includes("EEG")
+    - intersects(dataset.modalities, ["eeg"])
   fields:
     EEGPlacementScheme: optional
     CapManufacturer: optional
@@ -214,7 +214,7 @@ MEGCoordsystemAnatomicalMRI:
     - modality == "meg"
     - datatype == "meg"
     - suffix == "coordsystem"
-    - dataset.modalities.includes("anat")
+    - intersects(dataset.datatypes, ["anat"])
   fields:
     IntendedFor:
       level: optional
diff --git a/src/schema/rules/sidecars/mri.yaml b/src/schema/rules/sidecars/mri.yaml
index d8b61d58ae..e07a514ff0 100644
--- a/src/schema/rules/sidecars/mri.yaml
+++ b/src/schema/rules/sidecars/mri.yaml
@@ -35,6 +35,14 @@ MRIScannerHardware:
     MatrixCoilMode: recommended
     CoilCombinationMethod: recommended
 
+MRIScannerHardwareASL:
+  selectors:
+    - datatype == "perf"
+    - suffix == "asl"
+    - intersects([suffix], ["asl", "m0scan"])
+  fields:
+    MagneticFieldStrength: required
+
 MRISequenceSpecifics:
   selectors:
     - modality == "mri"
@@ -63,7 +71,7 @@ MRISequenceSpecifics:
 PETMRISequenceSpecifics:
   selectors:
     - modality == "mri"
-    - dataset.modalities.includes("PET")
+    - intersects(dataset.modalities, ["pet"])
   fields:
     NonlinearGradientCorrection: required
 
@@ -92,13 +100,13 @@ SpoilingType:
 
 SpoilingRF:
   selectors:
-    - '["RF", "COMBINED"].includes(sidecar.SpoilingType)'
+    - intersects([sidecar.SpoilingType], ["RF", "COMBINED"])
   fields:
     SpoilingRFPhaseIncrement: recommended
 
 SpoilingGradient:
   selectors:
-    - '["GRADIENT", "COMBINED"].includes(sidecar.SpoilingType)'
+    - intersects([sidecar.SpoilingType], ["GRADIENT", "COMBINED"])
   fields:
     SpoilingGradientMoment: recommended
     SpoilingGradientDuration: recommended
@@ -189,10 +197,28 @@ SliceTimingASL:
   selectors:
     - modality == "mri"
     - datatype == "perf"
-    - '["asl", "m0scan"].includes(suffix)'
+    - intersects([suffix], ["asl", "m0scan"])
     - sidecar.MRAcquisitionType == "2D"
   fields:
-    SliceTiming: required
+    EchoTime: required
+    SliceTiming:
+      level: required
+      issue:
+        code: SLICE_TIMING_NOT_DEFINED_2D_ASL
+        message: |
+          You should define `SliceTiming` for this file, because `SequenceType` is sets
+          to a 2D sequence. `SliceTiming` is the time at which each slice was
+          acquired within each volume (frame) of the acquisition. Slice timing
+          is not slice order -- rather, it is a list of times containing the
+          time (in seconds) of each slice acquisition in relation to the beginning
+          of volume acquisition. The list goes through the slices along the slice
+          axis in the slice encoding dimension (see below). Note that to ensure the
+          proper interpretation of the `SliceTiming` field, it is important to check
+          if the optional `SliceEncodingDirection` exists. In particular, if
+          `SliceEncodingDirection` is negative, the entries in `SliceTiming` are
+          defined in reverse order with respect to the slice axis, such that the
+          final entry in the `SliceTiming` list is the time of acquisition of slice 0.
+          Without this parameter slice time correction will not be possible.
 
 # This is technically for sparse sequences only, but I don't know how to encode that.
 # SliceTimingSparse:
@@ -210,7 +236,7 @@ MRIRFandContrast:
 MRIFlipAngleLookLockerFalse:
   selectors:
     - modality == "mri"
-    - sidecar.LookLocker == false
+    - sidecar.LookLocker != true
   fields:
     FlipAngle:
       level: recommended
diff --git a/src/schema/rules/sidecars/pet.yaml b/src/schema/rules/sidecars/pet.yaml
index d3dd1bf406..de3ecceb23 100644
--- a/src/schema/rules/sidecars/pet.yaml
+++ b/src/schema/rules/sidecars/pet.yaml
@@ -43,40 +43,23 @@ PETRadioChemistry:
       level: required
       description_addendum: |
         Corresponds to DICOM Tags (0008,0104) `CodeValue` and (0008,0104) `CodeMeaning`.
-    InjectedRadioactivity:
-      level: required
-    InjectedRadioactivityUnits:
-      level: required
-    InjectedMass:
-      level: required
-    InjectedMassUnits:
-      level: required
-    SpecificRadioactivity:
-      level: required
-    SpecificRadioactivityUnits:
-      level: required
-    ModeOfAdministration:
-      level: required
-    TracerRadLex:
-      level: recommended
-    TracerSNOMED:
-      level: recommended
-    TracerMolecularWeight:
-      level: recommended
-    TracerMolecularWeightUnits:
-      level: recommended
-    InjectedMassPerWeight:
-      level: recommended
-    InjectedMassPerWeightUnits:
-      level: recommended
-    SpecificRadioactivityMeasTime:
-      level: recommended
-    MolarActivity:
-      level: recommended
-    MolarActivityUnits:
-      level: recommended
-    MolarActivityMeasTime:
-      level: recommended
+    InjectedRadioactivity: required
+    InjectedRadioactivityUnits: required
+    InjectedMass: required
+    InjectedMassUnits: required
+    SpecificRadioactivity: required
+    SpecificRadioactivityUnits: required
+    ModeOfAdministration: required
+    TracerRadLex: recommended
+    TracerSNOMED: recommended
+    TracerMolecularWeight: recommended
+    TracerMolecularWeightUnits: recommended
+    InjectedMassPerWeight: recommended
+    InjectedMassPerWeightUnits: recommended
+    SpecificRadioactivityMeasTime: recommended
+    MolarActivity: recommended
+    MolarActivityUnits: recommended
+    MolarActivityMeasTime: recommended
     InfusionRadioactivity:
       level: recommended
       level_addendum: required if ModeOfAdministration is `'bolus-infusion'`
@@ -92,8 +75,7 @@ PETRadioChemistry:
     InjectedVolume:
       level: recommended
       level_addendum: required if ModeOfAdministration is `'bolus-infusion'`
-    Purity:
-      level: recommended
+    Purity: recommended
 
 # PET Infusion conditionally required entities
 EntitiesBolusMetadata:
@@ -102,16 +84,11 @@ EntitiesBolusMetadata:
     - suffix == "pet"
     - sidecar.ModeOfAdministration == 'bolus-infusion'
   fields:
-    InfusionRadioactivity:
-      level: required
-    InfusionStart:
-      level: required
-    InfusionSpeed:
-      level: required
-    InfusionSpeedUnits:
-      level: required
-    InjectedVolume:
-      level: required
+    InfusionRadioactivity: required
+    InfusionStart: required
+    InfusionSpeed: required
+    InfusionSpeedUnits: required
+    InjectedVolume: required
 
 PETPharmaceuticals:
   selectors:
@@ -124,34 +101,27 @@ PETPharmaceuticals:
     PharmaceuticalDoseAmount:
       level: recommended
       description_addendum: Corresponds to DICOM Tag (0008,0028) `Intervention Drug Dose`.
-    PharmaceuticalDoseUnits:
-      level: recommended
-    PharmaceuticalDoseRegimen:
-      level: recommended
+    PharmaceuticalDoseUnits: recommended
+    PharmaceuticalDoseRegimen: recommended
     PharmaceuticalDoseTime:
       level: recommended
       description_addendum: |
         Corresponds to a combination of DICOM Tags (0008,0027) `Intervention Drug Stop Time`
         and (0008,0035) `Intervention Drug Start Time`.
-    Anaesthesia:
-      level: optional
+    Anaesthesia: optional
 
 PETTime:
   selectors:
     - modality == "pet"
     - suffix == "pet"
   fields:
-    TimeZero:
-      level: required
-    ScanStart:
-      level: required
+    TimeZero: required
+    ScanStart: required
     InjectionStart:
       level: required
       description_addendum: Corresponds to DICOM Tag (0018,1072) `Radiopharmaceutical Start Time`.
-    FrameTimesStart:
-      level: required
-    FrameDuration:
-      level: required
+    FrameTimesStart: required
+    FrameDuration: required
     InjectionEnd:
       level: recommended
       description_addendum: |
@@ -166,12 +136,9 @@ PETReconstruction:
     - modality == "pet"
     - suffix == "pet"
   fields:
-    AcquisitionMode:
-      level: required
-    ImageDecayCorrected:
-      level: required
-    ImageDecayCorrectionTime:
-      level: required
+    AcquisitionMode: required
+    ImageDecayCorrected: required
+    ImageDecayCorrectionTime: required
     ReconMethodName:
       level: required
       description_addendum: This partly matches the DICOM Tag (0054,1103) `Reconstruction Method`.
@@ -193,12 +160,9 @@ PETReconstruction:
     AttenuationCorrection:
       level: required
       description_addendum: This corresponds to DICOM Tag (0054,1101) `Attenuation Correction Method`.
-    ReconMethodImplementationVersion:
-      level: recommended
-    AttenuationCorrectionMethodReference:
-      level: recommended
-    ScaleFactor:
-      level: recommended
+    ReconMethodImplementationVersion: recommended
+    AttenuationCorrectionMethodReference: recommended
+    ScaleFactor: recommended
     ScatterFraction:
       level: recommended
       description_addendum: Corresponds to DICOM Tag (0054,1323) `Scatter Fraction Factor`.
@@ -208,10 +172,9 @@ PETReconstruction:
     DoseCalibrationFactor:
       level: recommended
       description_addendum: Corresponds to DICOM Tag (0054,1322) `Dose Calibration Factor`.
-    PromptRate:
-      level: recommended
-    SinglesRate:
-      level: recommended
+    PromptRate: recommended
+    SinglesRate: recommended
+    RandomRate: recommended
 
 BloodRecording:
   selectors:
diff --git a/src/schema/rules/tabular_data/derivatives/common_derivatives.yaml b/src/schema/rules/tabular_data/derivatives/common_derivatives.yaml
index 1b3366af97..0cff803116 100644
--- a/src/schema/rules/tabular_data/derivatives/common_derivatives.yaml
+++ b/src/schema/rules/tabular_data/derivatives/common_derivatives.yaml
@@ -1,8 +1,8 @@
 ---
 SegmentationLookup:
   selectors:
-    - dataset.DatasetType == "derivative"
-    - '["dseg", "probseg"].includes(suffix)'
+    - dataset.dataset_description.DatasetType == "derivative"
+    - intersects([suffix], ["dseg", "probseg"])
   columns:
     index: required
     name__segmentations: required
diff --git a/tools/schemacode/bidsschematools/render.py b/tools/schemacode/bidsschematools/render.py
index 2e8eb0ae67..3348afaf55 100644
--- a/tools/schemacode/bidsschematools/render.py
+++ b/tools/schemacode/bidsschematools/render.py
@@ -774,7 +774,7 @@ def make_obj_table(
             "enum" in subschema[field].keys()
             and len(subschema[field]["enum"]) >= n_values_to_combine
         ):
-            glossary_entry = f"{GLOSSARY_PATH}.md#objects.{field}"
+            glossary_entry = f"{GLOSSARY_PATH}.md#objects.{field_type}.{field}"
             valid_values_str = (
                 "For a list of valid values for this field, see the "
                 f"[associated glossary entry]({glossary_entry})."