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hda

hda

MCP tool wrappers for Houdini Digital Asset (HDA) operations.

Each tool delegates to the corresponding handler running inside Houdini via the HTTP bridge.

Functions:

Name Description
create_hda

Create a new HDA from an existing subnet node.
edit_hda_interface

Edit an HDA's EXISTING Type Properties interface in one atomic call:
get_hda_info

Get detailed information about an HDA definition.
get_hda_section_content

Read the content of a specific section in an HDA definition.
get_hda_sections

List all sections in an HDA definition.
install_hda

Install an HDA file into the current session.
list_hda_versions

Every installed definition of an HDA node's type: version, file, which is current.
list_installed_hdas

List installed HDA definitions, grouped by library file.
reload_hda

Reload an HDA file from disk.
set_hda_interface

Author an HDA's Type Properties interface in one call.
set_hda_section_content

Write content to a specific section in an HDA definition.
uninstall_hda

Uninstall an HDA file from the current session.
update_hda

Save the current node contents back to its HDA definition.

Functions:

create_hda async 

create_hda(
    ctx: Context,
    node_path: str,
    hda_file: str,
    type_name: str,
    label: str,
    version: str = "1.0",
) -> dict

Create a new HDA from an existing subnet node.

Parameters:

Name Type Description Default
ctx
Context

MCP context.

 required
node_path
str

Subnet node path.

 required
hda_file
str

Destination HDA file path.

 required
type_name
str

Operator type name.

 required
label
str

Human-readable label.

 required
version
str

Version string.

 '1.0'

edit_hda_interface async 

edit_hda_interface(
    ctx: Context, node_path: str, ops: list[dict], dry_run: bool = False
) -> dict

Edit an HDA's EXISTING Type Properties interface in one atomic call: insert at a position, remove, hide/show, replace, modify, move.

set_hda_interface only appends. Every op here works on the definition's parameter group; all ops are applied to a copy, the result is checked for component-name collisions, and it is written once — a failing op changes nothing. Read the interface first with get_parm_template_tree.

Ops (dicts, applied in order): {"op": "insert", "spec": {...}, "after": name | "before": name | "in_folder": label or [labels]} — omit the position to append. spec is a set_hda_interface spec, plus types button (with "callback", Python by default), separator, label, vector, color, file, oppath; and fields naming_scheme (base1|xyzw|rgba|minmax| startend|uvw), default_expression (+ default_expression_language), hidden, join_with_next, callback, tags; folder_type "multiparm" for a multiparm block (children named "item#"). {"op": "remove", "name": name_or_folder_label} {"op": "hide" | "show", "name": ...} {"op": "replace", "name": ..., "spec": {...}} {"op": "modify", "name": ...,

Names are template names (t, not tx; stud_count); folders are addressed by label ("Controls"). Built-in parameters of the node type (an Object's Transform) cannot be removed — Houdini re-adds them at the top level and the reply says so in reinstated_by_houdini; hide them.

default_expression_language is "hscript" (Houdini's default) or "python"; given alone in a modify, it changes the language of the expression already there. stored reads both back, and instance_expression_errors names a default expression that does not evaluate on the instance.

Parameters:

Name Type Description Default
ctx
Context

MCP context.

 required
node_path
str

An instance of the HDA whose definition is edited.

 required
ops
list[dict]

Operations, in order.

 required
dry_run
bool

Validate and report the plan without writing.

 False

get_hda_info async 

get_hda_info(
    ctx: Context,
    node_path: str | None = None,
    hda_file: str | None = None,
    type_name: str | None = None,
) -> dict

Get detailed information about an HDA definition.

Parameters:

Name Type Description Default
ctx
Context

MCP context.

 required
node_path
str | None

Node path.

 None
hda_file
str | None

HDA file path.

 None
type_name
str | None

HDA type name.

 None

get_hda_section_content async 

get_hda_section_content(
    ctx: Context, node_path: str, section_name: str
) -> dict

Read the content of a specific section in an HDA definition.

Parameters:

Name Type Description Default
ctx
Context

MCP context.

 required
node_path
str

Node path.

 required
section_name
str

Section name.

 required

get_hda_sections async 

get_hda_sections(ctx: Context, node_path: str) -> dict

List all sections in an HDA definition.

Parameters:

Name Type Description Default
ctx
Context

MCP context.

 required
node_path
str

Node path.

 required

install_hda async 

install_hda(ctx: Context, file_path: str, force: bool = False) -> dict

Install an HDA file into the current session.

Parameters:

Name Type Description Default
ctx
Context

MCP context.

 required
file_path
str

HDA file path.

 required
force
bool

Force reinstall even if already loaded.

 False

list_hda_versions async 

list_hda_versions(ctx: Context, node_path: str) -> dict

Every installed definition of an HDA node's type: version, file, which is current.

Parameters:

Name Type Description Default
ctx
Context

MCP context.

 required
node_path
str

An HDA instance.

 required

list_installed_hdas async 

list_installed_hdas(
    ctx: Context, filter: str | None = None, limit: int = 100
) -> dict

List installed HDA definitions, grouped by library file.

A stock install loads thousands; pass a filter (namespace, name or path fragment). truncated says when limit cut the list.

Parameters:

Name Type Description Default
ctx
Context

MCP context.

 required
filter
str | None

Substring filter for type names or file paths.

 None
limit
int

Maximum definitions returned.

 100

reload_hda async 

reload_hda(ctx: Context, file_path: str) -> dict

Reload an HDA file from disk.

Parameters:

Name Type Description Default
ctx
Context

MCP context.

 required
file_path
str

HDA file path.

 required

set_hda_interface async 

set_hda_interface(
    ctx: Context,
    node_path: str,
    parameters: list[dict],
    replace: bool = False,
    dry_run: bool = False,
) -> dict

Author an HDA's Type Properties interface in one call.

Use this for the asset's TYPE interface — tab folders, strict ranges, ordered menus, Hide/Disable When. create_spare_parameter is a different thing: it adds parameters to one node instance and never reaches the type.

Each entry of parameters is a dict: name, label, type (int|float|string|toggle|menu|folder), default, min, max, min_strict, max_strict, components, menu_items ([value, label] pairs or plain strings), folder_type (tabs|simple|collapsible|radio) + children for folders, hide_when / disable_when (Houdini conditionals), help.

Example — a Controls tab whose Bevel disappears for a single stud: [{"name": "controls", "label": "Controls", "type": "folder", "children": [ {"name": "stud_count", "type": "int", "default": 4, "min": 1, "max": 8, "min_strict": True, "max_strict": True}, {"name": "bevel", "type": "float", "default": 0.02, "min": 0.0, "max": 0.1, "hide_when": "{ stud_count == 1 }"}, {"name": "material", "type": "menu", "menu_items": [["plastic", "Plastic"], ["metal", "Metal"]]}]}]

It is edit_hda_interface with one insert per entry: names already in the interface are refused before anything is written, and the reply is read back off the definition — ops[].stored, renamed_by_houdini (a tab folder joins the existing tab set's naming series), not_found_after_write, instance_parms_missing and instance_expression_errors.

Parameters:

Name Type Description Default
ctx
Context

MCP context.

 required
node_path
str

An instance of the HDA whose definition is edited.

 required
parameters
list[dict]

Interface spec (see above). create_spare_parameters' spelling (parm_name, parm_type, default_value) is accepted too.

 required
replace
bool

Start from an empty interface. Built-in parameters of the node type cannot be removed: Houdini puts them back (reinstated_by_houdini).

 False
dry_run
bool

Validate and report the plan without writing.

 False

set_hda_section_content async 

set_hda_section_content(
    ctx: Context, node_path: str, section_name: str, content: str
) -> dict

Write content to a specific section in an HDA definition.

Parameters:

Name Type Description Default
ctx
Context

MCP context.

 required
node_path
str

Node path.

 required
section_name
str

Section name.

 required
content
str

Section content.

 required

uninstall_hda async 

uninstall_hda(ctx: Context, file_path: str) -> dict

Uninstall an HDA file from the current session.

Parameters:

Name Type Description Default
ctx
Context

MCP context.

 required
file_path
str

HDA file path.

 required

update_hda async 

update_hda(ctx: Context, node_path: str) -> dict

Save the current node contents back to its HDA definition.

The definition's library file is written by this call: saved_to_disk and library_file_mtime say so, so no separate save is needed. An embedded definition lives in the hip file and is kept when the scene is saved.

Parameters:

Name Type Description Default
ctx
Context

MCP context.

 required
node_path
str

Node path.

 required