blender-python-api-verification

Verify Blender Python APIs

The visible host Blender process is the source of truth. This installation also provides the official Blender 5.1 Python API under:

/sandbox/reference/blender-python-api-5.1

Use scripts/search_blender_api.py with sandbox terminal tools to find relevant official documentation. The docs cover Blender itself, not OVRTX, OVPhysX, or other add-ons.

Required workflow

Before an uncertain Blender mutation:

1. Search the version-matched reference for the type or operator.
2. Make a separate, non-mutating mcp_blender_execute_blender_code call to inspect the running object, RNA properties, enum items, or operator RNA.
3. Check every uncertain property and enum value. Do not infer API availability from an older Blender example.
4. Only then make the mutation in a second Blender MCP call.
5. Return a compact receipt. Do not dump complete RNA schemas into chat.

Do not import bpy with sandbox Python. Blender MCP code runs inside Blender on the host; sandbox code does not.

Runtime inspection patterns

Inspect an RNA object:

target = bpy.context.scene.display.shading
props = target.bl_rna.properties
name = "type"
result = {
    "blender": bpy.app.version_string,
    "rna_type": target.bl_rna.identifier,
    "property_exists": name in props,
    "readonly": props[name].is_readonly if name in props else None,
    "enum_values": [item.identifier for item in props[name].enum_items]
        if name in props and props[name].type == "ENUM" else [],
}
print(result)

Inspect an operator before calling it:

operator = bpy.ops.wm.usd_import
rna = operator.get_rna_type()
print({
    "operator": rna.identifier,
    "properties": [p.identifier for p in rna.properties if p.identifier != "rna_type"],
    "poll": operator.poll(),
})

For non-RNA Python objects, use narrowly filtered dir() or hasattr(). Prefer direct data API operations over context-sensitive bpy.ops calls. If an operator is required, inspect poll() and establish its context explicitly.

Failure behavior

If the requested API is absent, read-only, has different enum values, or fails operator polling, stop before mutation and report the observed Blender version and API shape. Do not retry guessed property names or execute a long script that mixes discovery with destructive changes.