e1c17e047fAdd four new example servers demonstrating different SEP-2053 variant patterns: - model-optimized (same tools, different descriptions per LLM family) - trading (API versioning with deprecation lifecycle) - research (context budget management) - Refactor the existing variants-http example into a GitHub-style server with custom ranking. Signed-off-by: Kurt Degiorgio <kdegiorgio@bloomberg.net>
118 lines
3.1 KiB
Markdown
118 lines
3.1 KiB
Markdown
# Model-Optimized Weather Service
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A variant-aware MCP server that exposes the same tools (`get_weather`, `get_forecast`) with different descriptions optimized for different LLM families. This is the primary use case described in SEP-2053.
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**Pattern demonstrated:** Same tools, different descriptions per variant.
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## Variants
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| Variant | Description Style | Target |
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|---|---|---|
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| `claude-optimized` | Verbose, structured with explicit usage guidance | Anthropic Claude models |
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| `gpt-optimized` | Concise, function-style with JSON Schema emphasis | OpenAI GPT models |
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| `compact` | Minimal, bare-minimum descriptions | Context-constrained environments |
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All three variants expose the same two tools with the same behavior — only the tool descriptions differ.
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## Custom Ranking
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Clients send a `"modelFamily"` hint (e.g., `"anthropic"`, `"openai"`). The ranking function matches the hint to the variant's `modelFamily`, falling back to priority order.
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## Run
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```bash
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go run ./examples/server/model-optimized
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```
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The server listens on `http://localhost:8080`.
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Connect any MCP client to `http://localhost:8080`.
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## Try It
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### 1. Initialize without hints (default ranking)
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```bash
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curl -s -X POST http://localhost:8080/mcp \
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-H 'Content-Type: application/json' \
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-d '{
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"jsonrpc": "2.0", "id": 1,
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"method": "initialize",
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"params": {
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"protocolVersion": "2025-03-26",
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"clientInfo": {"name": "test", "version": "1.0"},
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"capabilities": {}
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}
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}'
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```
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The first variant in the response is the **default** — clients that don't specify a variant in subsequent requests will use it. Without hints, `claude-optimized` is the default:
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```json
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{
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"availableVariants": [
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{
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"id": "claude-optimized",
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"hints": { "contextSize": "verbose", "modelFamily": "anthropic" },
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"status": "stable"
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},
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{
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"id": "gpt-optimized",
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"hints": { "contextSize": "standard", "modelFamily": "openai" },
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"status": "stable"
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},
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{
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"id": "compact",
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"hints": { "contextSize": "compact", "modelFamily": "any" },
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"status": "stable"
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}
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]
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}
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```
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### 2. Initialize with an OpenAI hint (ranking changes)
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```bash
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curl -s -X POST http://localhost:8080/mcp \
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-H 'Content-Type: application/json' \
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-d '{
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"jsonrpc": "2.0", "id": 1,
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"method": "initialize",
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"params": {
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"protocolVersion": "2025-03-26",
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"clientInfo": {"name": "test", "version": "1.0"},
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"capabilities": {
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"experimental": {
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"io.modelcontextprotocol/server-variants": {
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"variantHints": {
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"hints": {"modelFamily": "openai"}
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}
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}
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}
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}
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}
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}'
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```
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Now `gpt-optimized` is ranked first and becomes the default:
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```json
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{
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"availableVariants": [
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{
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"id": "gpt-optimized",
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"hints": { "contextSize": "standard", "modelFamily": "openai" },
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"status": "stable"
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},
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{
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"id": "claude-optimized",
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"hints": { "contextSize": "verbose", "modelFamily": "anthropic" },
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"status": "stable"
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},
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{
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"id": "compact",
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"hints": { "contextSize": "compact", "modelFamily": "any" },
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"status": "stable"
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}
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]
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}
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```
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