fix(harness): harden Claude Code + OpenAI taps and span tracing

adk/docs/harness.md

@@ -198,3 +198,9 @@ result = await emitter.auto_send_turn(turn, created_at=workflow.now())
 # result.final_text — last text segment
 # result.usage     — TurnUsage (tokens, cost, ...)
 ```
+
+---
+
+## Migration
+
+- [Migrating to `agentex-client` 0.16.0 / `agentex-sdk` 0.15.0](./migration-0.16.0.md) — removed LangGraph/Pydantic-AI tracing handlers (tracing is now derived from the canonical stream), private `_modules` path moves, the OpenAI harness facade relocation, and the new `run_turn` Temporal entry point.

adk/docs/migration-0.16.0.md

@@ -0,0 +1,272 @@
+# Migration Guide — `agentex-client` 0.16.0 / `agentex-sdk` 0.15.0
+
+This release consolidates the LangGraph, Pydantic-AI, and OpenAI Agents harnesses
+onto the **unified harness surface** (`UnifiedEmitter` + `SpanDeriver`), introduces
+`run_turn` as the single Temporal entry point for OpenAI Agents, renders
+hosted/server-side tool calls in the Temporal streaming model, and ships new CLI
+init templates.
+
+Most consumers only need to act on **section 1** (removed tracing handlers).
+Sections 2–3 only matter if you import private modules. Section 4 lists the new,
+opt-in capabilities. Section 5 documents the defect fixes shipped on top of the
+release.
+
+---
+
+## 1. Tracing handlers removed (LangGraph + Pydantic-AI) — **action required**
+
+The bespoke tracing callback handlers are **gone** from the public
+`agentex.lib.adk` surface:
+
+| Removed | |
+|---|---|
+| `agentex.lib.adk.create_langgraph_tracing_handler` | + class `AgentexLangGraphTracingHandler` |
+| `agentex.lib.adk.create_pydantic_ai_tracing_handler` | + class `AgentexPydanticAITracingHandler` |
+
+Span tracing is now **derived automatically** from the canonical
+`StreamTaskMessage*` stream by `UnifiedEmitter`. You no longer construct or pass a
+callback handler — you wrap the run in the harness `*Turn` and drive delivery
+through the emitter, and spans fall out of the stream.
+
+### LangGraph
+
+**Before**
+
+```python
+from agentex.lib import adk
+
+handler = adk.create_langgraph_tracing_handler(
+    trace_id=trace_id,
+    parent_span_id=parent_span_id,
+)
+result = await graph.ainvoke(state, config={"callbacks": [handler]})
+```
+
+**After**
+
+```python
+from agentex.lib.adk import stream_langgraph_events  # facade name unchanged
+
+# Streaming delivery + tracing are handled for you; no callbacks wiring.
+async for event in stream_langgraph_events(graph, state, ...):
+    ...
+```
+
+or, when you own the emitter directly:
+
+```python
+from agentex.lib.adk import LangGraphTurn
+from agentex.lib.core.harness import UnifiedEmitter
+
+emitter = UnifiedEmitter(...)
+await emitter.auto_send_turn(LangGraphTurn(...))   # or: emitter.yield_turn(...)
+```
+
+### Pydantic-AI
+
+**Before**
+
+```python
+handler = adk.create_pydantic_ai_tracing_handler(trace_id=..., parent_span_id=...)
+```
+
+**After**
+
+```python
+from agentex.lib.adk import PydanticAITurn, stream_pydantic_ai_events
+from agentex.lib.core.harness import UnifiedEmitter
+
+# Wrap in PydanticAITurn and drive UnifiedEmitter.yield_turn / auto_send_turn.
+await UnifiedEmitter(...).auto_send_turn(PydanticAITurn(...))
+```
+
+The `agentex init` templates were migrated to this pattern. If you scaffolded
+from an older template, regenerate (or diff against a fresh template) for the
+canonical shape.
+
+---
+
+## 2. Private `_modules` import paths changed — **only if you import privates**
+
+Each harness now exposes exactly `_<harness>_sync.py` + `_<harness>_turn.py` under
+`agentex.lib.adk._modules`. Several private modules were deleted and their
+functions relocated. If you imported the **public facade names** from
+`agentex.lib.adk`, **nothing changes**. Repoint only if you reached into the
+private modules directly:
+
+| Old (deleted) private import | New location | Public facade (unchanged) |
+|---|---|---|
+| `_modules._langgraph_async.stream_langgraph_events` | `_modules._langgraph_turn` | `adk.stream_langgraph_events` |
+| `_modules._langgraph_messages.emit_langgraph_messages` | `_modules._langgraph_sync` | `adk.emit_langgraph_messages` |
+| `_modules._langgraph_tracing.*` | **removed** (see §1) | — |
+| `_modules._pydantic_ai_async.stream_pydantic_ai_events` | `_modules._pydantic_ai_turn` | `adk.stream_pydantic_ai_events` |
+| `_modules._pydantic_ai_tracing.*` | **removed** (see §1) | — |
+
+✅ These facade names are unchanged and keep working:
+`stream_langgraph_events`, `emit_langgraph_messages`,
+`convert_langgraph_to_agentex_events`, `LangGraphTurn`,
+`stream_pydantic_ai_events`, `convert_pydantic_ai_to_agentex_events`,
+`PydanticAITurn`.
+
+---
+
+## 3. OpenAI harness moved into `adk/_modules` + facade export
+
+The OpenAI Agents harness now lives alongside the others:
+
+- `OpenAITurn`, `openai_usage_to_turn_usage` → `agentex.lib.adk._modules._openai_turn`
+- `convert_openai_to_agentex_events` → `agentex.lib.adk._modules._openai_sync`
+
+New **public** facade exports (prefer these):
+
+```python
+from agentex.lib.adk import (
+    OpenAITurn,
+    convert_openai_to_agentex_events,
+    openai_usage_to_turn_usage,
+)
+```
+
+Back-compat shims remain at
+`agentex.lib.adk.providers._modules.{openai_turn,sync_provider}` **for one
+release** — migrate to the facade names before the next minor.
+
+---
+
+## 4. New capabilities (opt-in, no migration required)
+
+- **`run_turn` — unified Temporal entry point for OpenAI Agents.**
+
+  ```python
+  from agentex.lib.core.temporal.plugins.openai_agents import run_turn, OpenAIAgentsTurnResult
+
+  result = await run_turn(
+      agent, input,
+      task_id=task_id,
+      trace_id=trace_id,
+      parent_span_id=parent_span_id,
+  )
+  result.final_output   # raw SDK final_output
+  result.usage          # normalized TurnUsage for the turn span
+  ```
+
+  It emits each tool call exactly once (the streaming model is the sole
+  tool-**request** emitter; hooks emit tool **responses**), traces per-tool spans,
+  normalizes token usage, and drains orphaned tool spans in a `finally` block if
+  the run terminates mid-tool. Existing `TemporalStreamingHooks` callers keep
+  working — `run_turn` is additive. If you pass your own `hooks` subclass, also
+  set `emit_tool_requests=False` and forward `trace_id` / `parent_span_id`
+  yourself (they are only auto-applied to the default hooks).
+
+- **Hosted / server-side tool rendering** in `TemporalStreamingModel`:
+  web_search, file_search, code_interpreter, image_generation, server-side mcp,
+  computer, and local_shell calls now surface as ToolRequest/ToolResponse pairs.
+
+- **New CLI init templates:** `default` / `sync` / `temporal` flavors of
+  `claude-code` and `codex`, plus `default-openai-agents`.
+
+---
+
+## 5. Defect fixes shipped with this migration
+
+These fixes harden the newly-added sync OpenAI converter
+(`convert_openai_to_agentex_events` / `OpenAITurn`) and the Temporal hosted-tool
+path. No API change — behavior only.
+
+1. **Malformed tool arguments no longer abort the turn.** The converter now
+   parses raw tool-call arguments through a defensive helper
+   (`_safe_parse_arguments`): a non-decodable string is preserved under `raw`
+   and a non-dict JSON value under `value`, instead of raising `JSONDecodeError`
+   and killing the run before later output is delivered. This matches the
+   Temporal streaming model's existing fallback.
+
+2. **Reasoning messages are closed.** Completed reasoning content/summary items
+   now emit a matching `StreamTaskMessageDone`. Previously the `Done` was
+   skipped, so `UnifiedEmitter.auto_send` never released the context and the
+   reasoning span could be marked incomplete (reasoning-model output appeared to
+   hang).
+
+3. **Text no longer collides with reasoning.** Every new text `item_id` now
+   reserves a fresh message index (matching the increment-then-use convention of
+   the reasoning/tool paths). Previously the first text item reused the current
+   index, so on reasoning-model streams the final answer could overwrite the
+   reasoning message, duplicate a `Start`, or route deltas into the wrong context.
+
+4. **Hosted-tool response shape aligned.** Hosted/server-side tool responses in
+   `TemporalStreamingModel` now emit `content` as a plain string, matching the
+   function-tool response path (`on_tool_end`) so hosted and function tools
+   render identically within the same flow.
+
+5. **Reasoning text now appears in derived spans.** `SpanDeriver` opened reasoning
+   spans with empty input and closed them with `output=None`, so reasoning/thinking
+   text never reached the trace (spans showed blank — read as "0 reasoning traces").
+   It now accumulates the `ReasoningContentDelta` / `ReasoningSummaryDelta` text (and
+   any text seeded on the Start content) and records it as the span output. Affects
+   every harness that streams reasoning, including the Claude Code tap.
+
+6. **Claude Code: no more duplicate text messages.** The `stream-json` converter
+   deduped streamed-vs-materialized blocks by numeric block index and reset that
+   state after every materialized `assistant` envelope. A single streamed message
+   that materializes as several envelopes (thinking, then text) lost the dedup
+   marker between envelopes and re-emitted the text. Dedup is now **content-based**
+   (match the streamed block's text, consume once), which a numeric index cannot do
+   reliably.
+
+> Action: if you adopted `OpenAITurn` for **reasoning models** (o1/o3/gpt-5) on
+> the sync path before these fixes, upgrade — fixes 2 and 3 are required for
+> correct reasoning rendering. Claude Code agents on the unified harness tap should
+> upgrade for fixes 5 and 6.
+
+---
+
+## 6. Legacy Temporal `claude_agents` plugin → unified harness tap
+
+`agentex.lib.core.temporal.plugins.claude_agents` (`run_claude_agent_activity`,
+`create_streaming_hooks`, `TemporalStreamingHooks`, `ClaudeMessageHandler`) is the
+**original** Claude Code integration: it drives the Python `claude-agent-sdk`
+directly and hand-rolls its own streaming + tracing. It is **superseded** by the
+unified harness tap and slated for removal in a future release. It still works
+today, so this migration is **recommended, not yet required** — but new Claude Code
+agents should use the tap, and existing ones should plan to move.
+
+Why migrate: the tap routes Claude Code through the same canonical
+`StreamTaskMessage*` stream as every other harness, so it gets central span
+derivation (tool **and** reasoning spans), the single delivery path
+(`UnifiedEmitter`), and fixes like the two above for free. The legacy plugin does
+not derive reasoning spans at all and duplicates the streaming/tracing logic.
+
+**Before — legacy plugin activity:**
+
+```python
+from agentex.lib.core.temporal.plugins.claude_agents import run_claude_agent_activity
+
+# In the workflow:
+result = await workflow.execute_activity(
+    run_claude_agent_activity,
+    args=[prompt, workspace_path, allowed_tools, ...],
+    start_to_close_timeout=...,
+)
+```
+
+**After — unified harness tap.** Run the CLI yourself (`claude -p --output-format
+stream-json --include-partial-messages`), wrap its stdout in `ClaudeCodeTurn`, and
+deliver through `UnifiedEmitter`:
+
+```python
+from agentex.lib.adk import ClaudeCodeTurn, UnifiedEmitter
+
+# `stdout_lines` is an async iterator of the CLI's stdout lines (raw JSON strings
+# or pre-parsed dicts) — e.g. read from sandbox.exec() / a subprocess.
+turn = ClaudeCodeTurn(stdout_lines)
+
+emitter = UnifiedEmitter(task_id=task_id, trace_id=trace_id, parent_span_id=parent_span_id)
+result = await emitter.auto_send_turn(turn, created_at=workflow.now())
+# result.final_text — last text segment
+# result.usage      — TurnUsage (tokens, cost, num_reasoning_blocks, ...)
+```
+
+The golden agent is the reference implementation
+(`teams/sgp/agents/golden_agent/project/harness/`): it spawns the CLI in a sandbox,
+yields stdout lines into `ClaudeCodeTurn`, and drives `auto_send_turn`. Known
+remaining consumers to migrate: the `090_claude_agents_sdk_mvp` tutorial and the
+`eval_dashboard_agent`.