(WIP) Redesign agentic-kit core around structured streams and add minimal agent runtime

[yyyyaaa]

This PR rewrites agentic-kit from a thin text-generation adapter layer into a structured provider portability layer, and introduces a separate @agentic-kit/agent runtime package for
sequential tool execution.

The new architecture is based on the redesign decisions captured in REDESIGN_DECISIONS.md. It preserves a compatibility path for the existing AgentKit.generate() flow while establishing the
new long-term API around:

• provider-independent model descriptors
• structured message/content types
• event-based streaming
• model/provider registries
• cross-provider message normalization
• a minimal stateful agent loop as a separate package

Why

The repo was previously too thin to serve as a serious provider-agnostic foundation in Constructive.

Before this PR, the library mostly offered:

• provider switching
• prompt/messages passthrough
• plain text streaming via chunk callbacks

It did not have:

• a normalized message/content model
• tool call protocol
• reasoning/thinking content
• usage/cost metadata
• abort/stop semantics
• cross-provider replay/handoff rules
• a distinct agent runtime layer

This PR addresses those gaps systematically.

What Changed

Core agentic-kit redesign

Added new core modules in packages/agentic-kit/src/:

• types.ts
• event-stream.ts
• messages.ts
• model-registry.ts
• provider-registry.ts
• transform-messages.ts

These introduce:

• ModelDescriptor
• Context
• Message / AssistantMessage / ToolResultMessage
• content blocks for text, image, thinking, and toolCall
• Usage and StopReason
• structured AssistantMessageEvent streaming
• model and provider registration APIs
• cross-provider message normalization and synthetic tool-result insertion

New top-level core API

packages/agentic-kit/src/index.ts now exposes structured primitives:

• stream(model, context, options)
• complete(model, context, options)
• completeText(model, context, options)
• model/provider registry helpers

The old AgentKit class remains as a transition-layer compatibility wrapper.

Compatibility wrapper retained

The legacy prompt-oriented API still works for one transition release through:

• AgentKit
• createOpenAIKit
• createAnthropicKit
• createOllamaKit
• createMultiProviderKit

That wrapper now delegates into the structured event-stream architecture instead of being the primary abstraction.

OpenAI-compatible adapter rewrite

packages/openai/src/index.ts was rewritten around the new contract.

It now supports:

• provider/model descriptors
• structured streaming events
• partial JSON parsing for tool calls
• usage tracking from streaming chunks
• reasoning-aware request shaping
• generalized OpenAI-compatible behavior rather than a brand-specific text adapter

Anthropic adapter rewrite

packages/anthropic/src/index.ts was rewritten to the same structured protocol.

It now supports:

• message/tool schema translation
• SSE event parsing into structured events
• Anthropic tool-use streaming
• thinking block streaming
• usage tracking and stop reasons

Ollama adapter rewrite

packages/ollama/src/index.ts now includes:

• retained OllamaClient functionality for model listing, pull/delete, and embeddings
• a structured OllamaAdapter
• streaming through the new assistant event model
• updated tests that validate the new API shape

New @agentic-kit/agent package

Added a new package at packages/agent/.

This package provides a minimal v1 runtime:

• sequential tool execution
• lifecycle events
• abort and continue support
• pluggable context transforms
• lightweight JSON Schema validation

This intentionally does not yet include richer steering/follow-up orchestration. The goal is to keep the first runtime layer minimal and validate the architecture first.

Docs and design record

Added:

• REDESIGN_DECISIONS.md

Updated:

• root README.md
• packages/agentic-kit/README.md
• packages/ollama/README.md

This also removes stale Ollama documentation that referenced methods no longer present in code.

Test coverage refresh

Replaced old tests that assumed string-only adapter behavior with new tests covering:

• structured OpenAI-compatible streaming
• Anthropic tool-use streaming
• Ollama structured streaming
• cross-provider message transforms
• legacy compatibility wrapper behavior
• minimal agent runtime loop

Migration Notes

This PR changes the architectural center of gravity, but keeps a compatibility path.

The intended migration path is:

• old style: kit.generate({ model, prompt }, { onChunk })
• new style: stream(model, context, options) or complete(model, context, options)

Legacy usage still works, but the structured API is now the primary contract.

Verification

Executed successfully:

• pnpm install
• pnpm -r build
• pnpm -r test

Additional smoke checks performed:

• required CJS dist output from packages/agentic-kit/dist/index.js
• imported ESM dist output from packages/agentic-kit/dist/esm/index.js
• imported ESM dist output from packages/agent/dist/esm/index.js

Infra / Packaging Notes

I found and fixed one real infra issue during this work:

• ESM output initially emitted extensionless relative imports, which Node could not load from dist/esm.

Fix applied:

• internal source imports/exports in the core and agent packages now use .js specifiers
• Jest config was updated to map those .js relative imports back to TS sources during tests

Current remaining caveat:

• importing dist/esm/*.js by file path triggers Node’s MODULE_TYPELESS_PACKAGE_JSON warning because the generated dist/package.json is not marked "type": "module"
• this does not break builds, tests, or ESM loading, but it is still worth tightening in a follow-up if we want cleaner Node ESM ergonomics

Follow-ups

Recommended next follow-ups after this PR:

• expand the curated built-in model registry
• add richer provider compatibility handling beyond the initial set
• add optional schema helpers for TypeBox/Zod
• decide how to package ESM more cleanly to eliminate the remaining Node warning
• add richer @agentic-kit/agent orchestration only after the lower-level protocol proves stable

Files of Interest

Core:

• packages/agentic-kit/src/index.ts
• packages/agentic-kit/src/types.ts
• packages/agentic-kit/src/event-stream.ts
• packages/agentic-kit/src/messages.ts
• packages/agentic-kit/src/model-registry.ts
• packages/agentic-kit/src/provider-registry.ts
• packages/agentic-kit/src/transform-messages.ts

Adapters:

• packages/openai/src/index.ts
• packages/anthropic/src/index.ts
• packages/ollama/src/index.ts

Agent runtime:

• packages/agent/src/agent.ts
• packages/agent/src/types.ts
• packages/agent/src/validation.ts

Design record:

• REDESIGN_DECISIONS.md

[yyyyaaa]

added live ollama tests