compare_variants_same_gene

Instructions

Implementation Reference

• scripts/alphagenome_bridge.py:552-577 (handler)

  Core handler function that executes the tool logic: processes list of variants, predicts effects using AlphaGenome API via predict_variant_effect helper, ranks by absolute expression fold change, returns ranked results with gene context.

  def compare_variants_same_gene(client, params: Dict[str, Any]) -> Dict[str, Any]:
      """Compare multiple variants in the same gene."""
      variants_data = params.get('variants', [])
      gene = params.get('gene', 'unknown')
  
      results = []
      for v in variants_data:
          try:
              result = predict_variant_effect(client, v)
              results.append({
                  'variant': result['variant'],
                  'impact': result['interpretation']['impact_level'],
                  'expression_fc': result['predictions'].get('rna_seq', {}).get('fold_change', 0),
                  'clinical_sig': result['interpretation']['clinical_significance']
              })
          except Exception as e:
              print(f"Warning: Failed: {e}", file=sys.stderr)
              continue
  
      results.sort(key=lambda x: abs(x['expression_fc']), reverse=True)
      return {
          'gene': gene,
          'total_variants': len(results),
          'ranked_variants': results
      }

• src/index.ts:235-240 (handler)

  MCP server request handler case for the tool: validates (implicitly), calls client proxy, formats result as JSON text content.

  case 'compare_variants_same_gene': {
    const result = await getClient().compareVariantsSameGene(args);
    return {
      content: [{ type: 'text', text: JSON.stringify(result, null, 2) }],
    };
  }

• src/tools.ts:547-580 (schema)

  Input schema definition for the tool: requires array of at least 2 variants (each with chr, pos, ref, alt), optional gene_name.

  export const COMPARE_VARIANTS_SAME_GENE_TOOL: Tool = {
    name: 'compare_variants_same_gene',
    description: `Compare multiple variants within the same gene.
  
  Ranks variants by impact within a single gene context.
  
  Perfect for: gene-level analysis, compound heterozygote analysis.
  
  Example: "Compare 5 BRCA1 variants"`,
    inputSchema: {
      type: 'object',
      properties: {
        variants: {
          type: 'array',
          items: {
            type: 'object',
            properties: {
              chromosome: { type: 'string' },
              position: { type: 'number' },
              ref: { type: 'string' },
              alt: { type: 'string' },
            },
            required: ['chromosome', 'position', 'ref', 'alt'],
          },
          minItems: 2,
        },
        gene_name: {
          type: 'string',
          description: 'Optional: gene name for context',
        },
      },
      required: ['variants'],
    },
  };

• src/index.ts:235-240 (registration)

  Tool dispatch registration in MCP CallToolRequestSchema handler switch statement.

  case 'compare_variants_same_gene': {
    const result = await getClient().compareVariantsSameGene(args);
    return {
      content: [{ type: 'text', text: JSON.stringify(result, null, 2) }],
    };
  }

• src/tools.ts:724-724 (registration)

  Tool registration in ALL_TOOLS export array used by ListToolsRequestSchema handler.

  COMPARE_VARIANTS_SAME_GENE_TOOL,

• src/alphagenome-client.ts:400-407 (handler)

  Client proxy method that spawns Python bridge subprocess with action='compare_variants_same_gene' and params, handles errors.

  async compareVariantsSameGene(params: any): Promise<any> {
    try {
      return await this.callPythonBridge('compare_variants_same_gene', params);
    } catch (error) {
      if (error instanceof ApiError) throw error;
      throw new ApiError(`Same-gene variant comparison failed: ${error}`, 500);
    }
  }