onebusaway-mcp-server: Instructions file for Claude Code

Developer Protocol

Server: onebusaway-mcp-server Version: 0.1.14 Package: @cyanheads/onebusaway-mcp-server Framework: @cyanheads/mcp-ts-core ^0.12.3 Engines: Bun ≥1.3.0, Node ≥24.0.0 MCP SDK: @modelcontextprotocol/server ^2.0.0 Zod: ^4.4.3

Read the framework docs first: node_modules/@cyanheads/mcp-ts-core/CLAUDE.md contains the full API reference — builders, Context, error codes, exports, patterns. This file covers server-specific conventions only.

Core Rules

• Logic throws, framework catches. Tool/resource handlers are pure — throw on failure, no try/catch. Plain Error is fine; the framework catches, classifies, and formats. Use error factories (notFound(), validationError(), etc.) when the error code matters.
• Use ctx.log for request-scoped logging. No console calls.
• Use ctx.state for tenant-scoped storage. Never access persistence directly.
• Need input the caller didn't supply? return ctx.requestInput(...) and read ctx.inputs when the handler is re-entered. Never await for user input mid-handler.
• Secrets in env vars only — never hardcoded.
• Close the loop on issues. When implementing work tracked by a GitHub issue, comment on the issue with what landed and close it. Do both — a comment without a close leaves stale issues open; a close without a comment leaves no record of what shipped. The comment is for future readers — state the concrete changes, not the conversation that produced them.

Patterns

Tool

import { tool, z } from '@cyanheads/mcp-ts-core';
import { JsonRpcErrorCode } from '@cyanheads/mcp-ts-core/errors';
import { getOneBusAwayService } from '@/services/onebusaway/onebusaway-service.js';

export const getStop = tool('onebusaway_get_stop', {
  title: 'Get Stop Details',
  description: 'Fetch details for a specific stop by ID.',
  annotations: { readOnlyHint: true },
  input: z.object({
    stopId: z.string().min(1).describe('Agency-prefixed stop ID (e.g. "1_75403").'),
  }),
  output: z.object({
    id: z.string().describe('Agency-prefixed stop ID.'),
    name: z.string().describe('Stop name.'),
    routeIds: z.array(z.string()).describe('IDs of routes that serve this stop.'),
  }),
  errors: [
    {
      reason: 'stop_not_found',
      code: JsonRpcErrorCode.NotFound,
      when: 'Stop ID does not exist on this instance.',
      recovery: 'Search for the stop with onebusaway_find_stops or onebusaway_search_stops to get a valid ID.',
    },
  ],

  async handler(input, ctx) {
    const stop = await getOneBusAwayService().getStop(input.stopId, ctx);
    ctx.log.info('getStop completed', { stopId: input.stopId });
    return stop;
  },

  format: (result) => [{
    type: 'text',
    text: `## ${result.name}\n**ID:** ${result.id}\n**Routes:** ${result.routeIds.join(', ')}`,
  }],
});