remotion-dev/remotion · error · Error

Composition not found.

Error message

Composition ${compositionName} not found.

What it means

The Web MCP selectSequence tool validates sequenceId at runtime: it must be a non-empty string. Numbers, null, or '' throw this error.

Solutions

1. Pass a non-empty string sequenceId matching a <Sequence id> in the current composition
2. Give your <Sequence> components explicit ids so they can be addressed

if (typeof sequenceId !== 'string' || sequenceId.length === 0) { /* reject */ }

const isNonEmptyString = (v: unknown): v is string => typeof v === 'string' && v.length > 0;

When it happens

Trigger: Calling the selectSequence MCP tool with sequenceId: '' or a non-string value.

Common situations: LLM MCP clients passing an empty id or a numeric id from timeline metadata.

Related errors

• assetPath must be a non-empty public-folder path, or an…
• frame must be an integer.
• No composition is currently selected.
• Sequence not found in the current composition.
• Studio sequence selection is unavailable.

AI-assisted analysis of remotion-dev/remotion@46a3a6bf13 (2026-08-28). Data as JSON: /api/errors/5ff2f20d3a9a4a86. Report an issue: GitHub.

Appendix: source

Thrown at packages/studio/src/components/WebMcp.tsx:912

							compositionName: {
								type: 'string',
								description: 'The name of the composition to open.',
							},
						},
						required: ['compositionName'],
						additionalProperties: false,
					},
					annotations: {readOnlyHint: false},
					execute: ({compositionName}) => {
						if (typeof compositionName !== 'string') {
							throw new Error('compositionName must be a string.');
						}

						const composition = compositionsRef.current.find(
							(candidate) => candidate.id === compositionName,
						);
						if (!composition) {
							throw new Error(`Composition ${compositionName} not found.`);
						}

						selectComposition(composition, true);
						return Promise.resolve({
							currentContent: {
								type: 'composition',
								compositionId: composition.id,
							},
						});
					},
				},
				{signal: controller.signal},
			),
			modelContext.registerTool(
				{
					name: 'get_sequences',
					title: 'Get Studio sequences',
					description:

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