Go: Agent Framework implementation (Phases 1-2)

[juliomenendez]

Summary

• Phase 1 — Hello Agent: Core types (Message, Content, Role), ChatClient interface, BaseAgent with functional options, OpenAI provider implementation
• Phase 2 — Middleware + Observability: Three-level middleware pipeline (agent, chat, function), OpenTelemetry tracing & metrics middleware, slog logging middleware

What's included

22 new files, 1,784 lines of Go code under go/:

Package	What
agentframework (root)	Core types, interfaces, agent, middleware pipeline
agentframework/openai	OpenAI ChatClient implementation
agentframework/observability	OTel tracing, metrics, slog logging middleware

15 test functions (38 subtests) — all passing. go vet clean.

Stacked PRs — Complete Go Implementation

This is the first in a series of stacked PRs implementing the full Go Agent Framework:

PR	Phase	What
#5131	1-2	Hello Agent + Middleware & Observability
juliomenendez#1	3	Streaming (scanner pattern)
juliomenendez#2	4	Tools (reflection schema, invocation loop)
juliomenendez#3	5	Multi-Turn (sessions, history, context providers)
juliomenendez#4	6	Compaction (truncation, sliding window, summarization)
juliomenendez#5	7	Workflows (graph DAG, executors, fan-out/in, checkpoints)
juliomenendez#6	8+12	Multi-Agent Patterns + HTTP Hosting
juliomenendez#7	9+10	MCP Integration + Skills
juliomenendez#8	11	Evaluation Framework

10 packages, 12 phases, all tests passing across the full stack.

Design

See docs/superpowers/specs/2026-04-06-golang-implementation-design.md (not committed) for the full design spec.

Test plan

• go test ./... -count=1 — all tests pass
• go vet ./... — no issues
• go mod tidy — module is clean
• Manual integration test with real OpenAI API key (not in CI)

🤖 Generated with Claude Code