AppSignal MCP Server

Implementation Reference

• src/mcp/server.ts:144-172 (registration)

  Registration of the 'getIncidentSample' MCP tool, including input schema and thin wrapper handler that delegates to AppSignalClient.getIncidentSample and returns JSON.

  this.server.tool(
    'getIncidentSample',
    {
      incidentNumber: z.number().int().positive(),
      sampleId: z.string().optional(),
    },
    async ({ incidentNumber, sampleId }) => {
      try {
        const sample = await this.client.getIncidentSample(incidentNumber, sampleId);
        return {
          content: [{
            type: 'text',
            text: JSON.stringify(sample, null, 2),
          }],
        };
      } catch (error) {
        if (error instanceof Error) {
          return {
            content: [{
              type: 'text',
              text: `Error fetching incident sample: ${error.message}`,
            }],
            isError: true,
          };
        }
        throw error;
      }
    }
  );

• src/appsignal/client.ts:143-203 (handler)

  Primary handler logic in AppSignalClient that executes GraphQL query to retrieve the incident sample from AppSignal API.

  async getIncidentSample(incidentNumber: number, sampleId?: string): Promise<Sample> {
    const query = `
      query IncidentSampleQuery($appId: String!, $incidentNumber: Int!, $sampleId: String) {
        app(id: $appId) {
          id
          incident(incidentNumber: $incidentNumber) {
            ... on ExceptionIncident {
              sample(id: $sampleId) {
                id
                appId
                time
                revision
                action
                namespace
                overview {
                  key
                  value
                }
                exception {
                  name
                  message
                  backtrace {
                    original
                    line
                    column
                    path
                    method
                    url
                    type
                    code {
                      line
                      source
                    }
                    error {
                      class
                      message
                    }
                  }
                }
              }
            }
          }
        }
      }
    `;
  
    const result = await this.executeQuery<{
      app: {
        id: string;
        incident: {
          sample: Sample;
        };
      };
    }>(query, {
      appId: this.appId,
      incidentNumber,
      sampleId,
    });
  
    return result.app.incident.sample;
  }

• src/appsignal/client.ts:22-54 (schema)

  Zod schema defining the structure of Sample data used for typing the response from getIncidentSample.

  export const SampleSchema = z.object({
    id: z.string(),
    appId: z.string(),
    time: z.string(),
    revision: z.string().optional(),
    action: z.string(),
    namespace: z.string(),
    overview: z.array(z.object({
      key: z.string(),
      value: z.string(),
    })),
    exception: z.object({
      name: z.string(),
      message: z.string(),
      backtrace: z.array(z.object({
        original: z.string().optional(),
        line: z.number().optional(),
        column: z.number().optional(),
        path: z.string().optional(),
        method: z.string().optional(),
        url: z.string().optional(),
        type: z.string().optional(),
        code: z.object({
          line: z.number().optional(),
          source: z.string().optional(),
        }).optional(),
        error: z.object({
          class: z.string().optional(),
          message: z.string().optional(),
        }).optional(),
      })),
    }),
  });

• src/mcp/server.ts:146-149 (schema)

  Input schema (Zod) for the getIncidentSample MCP tool parameters: incidentNumber (required positive int) and optional sampleId.

  {
    incidentNumber: z.number().int().positive(),
    sampleId: z.string().optional(),
  },