imf-mcp-server: Instructions file for Claude Code

Developer Protocol

Server: imf-mcp-server Version: 0.5.0 Framework: @cyanheads/mcp-ts-core ^0.13.18 Engines: Bun ≥1.4.0, Node ≥24.0.0 MCP SDK: @modelcontextprotocol/server ^2.4.0 Zod: ^4.6.7

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.

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Server Overview

imf-mcp-server wraps the IMF SDMX 3.0 public portal. No API key required.

Surface area: 6 tools, 1 resource, 0 prompts, plus the published agent skill imf-guide (skill://imf-guide/SKILL.md).

Workflow: imf_list_databases → imf_get_database → imf_query_dataset. Large result sets spill to DataCanvas — imf_dataframe_describe then imf_dataframe_query for SQL access.

Key constraints:

• Country codes are ISO 3-letter (USA, GBR, DEU — not US, GB, DE)
• Key format is dot-separated DSD dimension order (e.g. USA.NGDP_RPCH.A for WEO)
• DataCanvas is on by default (CANVAS_PROVIDER_TYPE=duckdb); none disables canvas spill and the dataframe tools

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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.
• Cut noise. Add only what earns its place: no speculative generality, no guards for states the framework already prevents (Zod-validated params, classified errors), no abstraction until a third caller proves it, no option nothing sets.
• 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.