Skip to main content
Glama

Set Keyframe

set_keyframe

Create or update a keyframe on a Cinema 4D parameter at a specified frame, with automatic track creation and support for scalar and vector values.

Instructions

Create or update a single keyframe on a resolved entity's parameter. Supports scalar (real/long/bool) and vector (x/y/z component) parameters; the bridge infers the dtype from the entity's description, or you can override it explicitly. Creates the CTrack automatically on first use.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
fpsNoTime base override (default: doc fps).
dtypeNoOverride the dtype when description lookup fails (rare).
frameYesFrame number.
valueYesValue at this frame (rotations in radians; bools coerce to 0/1).
handleYesEntity whose parameter gets the keyframe.
interpNoKey interpolation (default "spline").
param_idYesTop-level description id (e.g. c4d.ID_BASEOBJECT_REL_ROTATION = 904).
componentNoSub-component for Vector params. For C4D rotation (HPB) use "x" for H, "y" for P, "z" for B.

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

  1. Changed1 schema field changedv0.4.3
    • changedInput schema / definitions / __schema0 / anyOf
      Previous value: -[
      -  {
      -    "properties": {
      -      "kind": {
      -        "const": "object",
      -        "type": "string"
      -      },
      -      "name": {
      -        "type": "string"
      -      },
      -      "path": {
      -        "type": "string"
      -      }
      -    },
      -    "required": [
      -      "kind"
      -    ],
      -    "type": "object"
      -  },
      -  {
      -    "properties": {
      -      "kind": {
      -        "const": "render_data",
      -        "type": "string"
      -      },
      -      "name": {
      -        "type": "string"
      -      }
      -    },
      -    "required": [
      -      "kind",
      -      "name"
      -    ],
      -    "type": "object"
      -  },
      -  {
      -    "properties": {
      -      "kind": {
      -        "const": "take",
      -        "type": "string"
      -      },
      -      "name": {
      -        "type": "string"
      -      }
      -    },
      -    "required": [
      -      "kind",
      -      "name"
      -    ],
      -    "type": "object"
      -  },
      -  {
      -    "properties": {
      -      "kind": {
      -        "const": "material",
      -        "type": "string"
      -      },
      -      "name": {
      -        "type": "string"
      -      }
      -    },
      -    "required": [
      -      "kind",
      -      "name"
      -    ],
      -    "type": "object"
      -  },
      -  {
      -    "properties": {
      -      "kind": {
      -        "const": "tag",
      -        "type": "string"
      -      },
      -      "object": {
      -        "type": "string"
      -      },
      -      "object_path": {
      -        "type": "string"
      -      },
      -      "tag_name": {
      -        "type": "string"
      -      },
      -      "type_id": {
      -        "maximum": 9007199254740991,
      -        "minimum": -9007199254740991,
      -        "type": "integer"
      -      }
      -    },
      -    "required": [
      -      "kind"
      -    ],
      -    "type": "object"
      -  },
      -  {
      -    "properties": {
      -      "kind": {
      -        "const": "video_post",
      -        "type": "string"
      -      },
      -      "render_data": {
      -        "type": "string"
      -      },
      -      "type_id": {
      -        "maximum": 9007199254740991,
      -        "minimum": -9007199254740991,
      -        "type": "integer"
      -      }
      -    },
      -    "required": [
      -      "kind",
      -      "render_data",
      -      "type_id"
      -    ],
      -    "type": "object"
      -  },
      -  {
      -    "properties": {
      -      "index": {
      -        "maximum": 9007199254740991,
      -        "minimum": 0,
      -        "type": "integer"
      -      },
      -      "kind": {
      -        "const": "shader",
      -        "type": "string"
      -      },
      -      "name": {
      -        "type": "string"
      -      },
      -      "owner": {
      -        "allOf": [
      -          {
      -            "$ref": "#/definitions/__schema0"
      -          }
      -        ]
      -      }
      -    },
      -    "required": [
      -      "kind",
      -      "owner"
      -    ],
      -    "type": "object"
      -  },
      -  {
      -    "properties": {
      -      "id": {
      -        "type": "string"
      -      },
      -      "kind": {
      -        "const": "gv_node",
      -        "type": "string"
      -      },
      -      "name": {
      -        "type": "string"
      -      },
      -      "tag": {
      -        "allOf": [
      -          {
      -            "$ref": "#/definitions/__schema0"
      -          }
      -        ]
      -      }
      -    },
      -    "required": [
      -      "kind",
      -      "tag"
      -    ],
      -    "type": "object"
      -  },
      -  {
      -    "properties": {
      -      "kind": {
      -        "const": "plugin_options",
      -        "type": "string"
      -      },
      -      "plugin_id": {
      -        "anyOf": [
      -          {
      -            "maximum": 9007199254740991,
      -            "minimum": -9007199254740991,
      -            "type": "integer"
      -          },
      -          {
      -            "type": "string"
      -          }
      -        ]
      -      },
      -      "plugin_type": {
      -        "enum": [
      -          "command",
      -          "object",
      -          "tag",
      -          "material",
      -          "shader",
      -          "video_post",
      -          "scene_loader",
      -          "scene_saver",
      -          "bitmap_loader",
      -          "bitmap_saver",
      -          "tool",
      -          "preference",
      -          "node",
      -          "sculpt_brush"
      -        ],
      -        "type": "string"
      -      }
      -    },
      -    "required": [
      -      "kind",
      -      "plugin_id"
      -    ],
      -    "type": "object"
      -  }
      -]New value: +[
      +  {
      +    "properties": {
      +      "kind": {
      +        "const": "object",
      +        "type": "string"
      +      },
      +      "name": {
      +        "type": "string"
      +      },
      +      "path": {
      +        "type": "string"
      +      }
      +    },
      +    "required": [
      +      "kind"
      +    ],
      +    "type": "object"
      +  },
      +  {
      +    "properties": {
      +      "kind": {
      +        "const": "render_data",
      +        "type": "string"
      +      },
      +      "name": {
      +        "type": "string"
      +      }
      +    },
      +    "required": [
      +      "kind",
      +      "name"
      +    ],
      +    "type": "object"
      +  },
      +  {
      +    "properties": {
      +      "kind": {
      +        "const": "take",
      +        "type": "string"
      +      },
      +      "name": {
      +        "type": "string"
      +      }
      +    },
      +    "required": [
      +      "kind",
      +      "name"
      +    ],
      +    "type": "object"
      +  },
      +  {
      +    "properties": {
      +      "kind": {
      +        "const": "material",
      +        "type": "string"
      +      },
      +      "name": {
      +        "type": "string"
      +      }
      +    },
      +    "required": [
      +      "kind",
      +      "name"
      +    ],
      +    "type": "object"
      +  },
      +  {
      +    "properties": {
      +      "kind": {
      +        "const": "layer",
      +        "type": "string"
      +      },
      +      "name": {
      +        "type": "string"
      +      }
      +    },
      +    "required": [
      +      "kind",
      +      "name"
      +    ],
      +    "type": "object"
      +  },
      +  {
      +    "properties": {
      +      "kind": {
      +        "const": "tag",
      +        "type": "string"
      +      },
      +      "object": {
      +        "type": "string"
      +      },
      +      "object_path": {
      +        "type": "string"
      +      },
      +      "tag_name": {
      +        "type": "string"
      +      },
      +      "type_id": {
      +        "maximum": 9007199254740991,
      +        "minimum": -9007199254740991,
      +        "type": "integer"
      +      }
      +    },
      +    "required": [
      +      "kind"
      +    ],
      +    "type": "object"
      +  },
      +  {
      +    "properties": {
      +      "kind": {
      +        "const": "video_post",
      +        "type": "string"
      +      },
      +      "render_data": {
      +        "type": "string"
      +      },
      +      "type_id": {
      +        "maximum": 9007199254740991,
      +        "minimum": -9007199254740991,
      +        "type": "integer"
      +      }
      +    },
      +    "required": [
      +      "kind",
      +      "render_data",
      +      "type_id"
      +    ],
      +    "type": "object"
      +  },
      +  {
      +    "properties": {
      +      "index": {
      +        "maximum": 9007199254740991,
      +        "minimum": 0,
      +        "type": "integer"
      +      },
      +      "kind": {
      +        "const": "shader",
      +        "type": "string"
      +      },
      +      "name": {
      +        "type": "string"
      +      },
      +      "owner": {
      +        "allOf": [
      +          {
      +            "$ref": "#/definitions/__schema0"
      +          }
      +        ]
      +      }
      +    },
      +    "required": [
      +      "kind",
      +      "owner"
      +    ],
      +    "type": "object"
      +  },
      +  {
      +    "properties": {
      +      "id": {
      +        "type": "string"
      +      },
      +      "kind": {
      +        "const": "gv_node",
      +        "type": "string"
      +      },
      +      "name": {
      +        "type": "string"
      +      },
      +      "tag": {
      +        "allOf": [
      +          {
      +            "$ref": "#/definitions/__schema0"
      +          }
      +        ]
      +      }
      +    },
      +    "required": [
      +      "kind",
      +      "tag"
      +    ],
      +    "type": "object"
      +  },
      +  {
      +    "properties": {
      +      "kind": {
      +        "const": "plugin_options",
      +        "type": "string"
      +      },
      +      "plugin_id": {
      +        "anyOf": [
      +          {
      +            "maximum": 9007199254740991,
      +            "minimum": -9007199254740991,
      +            "type": "integer"
      +          },
      +          {
      +            "type": "string"
      +          }
      +        ]
      +      },
      +      "plugin_type": {
      +        "enum": [
      +          "command",
      +          "object",
      +          "tag",
      +          "material",
      +          "shader",
      +          "video_post",
      +          "scene_loader",
      +          "scene_saver",
      +          "bitmap_loader",
      +          "bitmap_saver",
      +          "tool",
      +          "preference",
      +          "node",
      +          "sculpt_brush"
      +        ],
      +        "type": "string"
      +      }
      +    },
      +    "required": [
      +      "kind",
      +      "plugin_id"
      +    ],
      +    "type": "object"
      +  }
      +]
  2. First observedv0.3.1

TDQS

A4.4/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Discloses key behavioral traits beyond what annotations provide: creates the CTrack automatically on first use, infers dtype from entity description with explicit override, supports scalar and vector components, rotations are in radians, bools coerce to 0/1. The description is transparent about mutation behavior even without annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, dense with value, no wasted words; front-loads the main behavior then details the dtype inference and auto-creation behavior. Under 300 characters and each sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the absence of annotations and output schema, the description covers the essential behavioral surface: what it does, the dtype mechanism, auto-creation, units for values. It doesn't state default interpolation behavior for the 'interp' parameter (that's in the schema: default spline), which is a minor gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the schema already documents parameters. The description adds context: dtype inference behavior for the 'dtype' parameter, the fact that 'value' uses radians, and the component mapping for rotation (HPB) for the 'component' parameter. This adds meaning beyond empty parameter naming.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('Create or update'), a precise resource ('single keyframe on a resolved entity's parameter'), and the scope is clear: scalar and vector parameters, with auto-creation of the CTrack. This distinguishes it from siblings like get_keyframes and delete_keyframe, and from set_params.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies its use case: setting keyframes on animated parameters over time, and mentions when dtype override is needed. It does not explicitly list when to prefer this over set_params, delete_keyframe, etc., but the context as keyframe creation is clear enough.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Latest Blog Posts

MCP directory API

We provide all the information about MCP servers via our MCP API.

curl -X GET 'https://glama.ai/api/mcp/v1/servers/kumoproductions/mcp-cinema4d'

If you have feedback or need assistance with the MCP directory API, please join our Discord server