fix: implement native Ollama thinking semantics

Model Ollama chat thinking separately from final content, preserve it only across assistant tool-call continuation, and keep private reasoning out of user results, session context, and logs.

Accept native boolean and low/medium/high/max think values, normalize YAML booleans, and serialize explicit overrides using the native top-level chat field.

Stop forcing think=false for structured planning, skill selection, and context summaries; corrected retries now retain the configured thinking mode.

Update the specification, design, audit report, and requirement traceability for OLL-14.

Add request/response, configuration, observability, retry, and tool-continuation coverage. Verified with 92 passing Agent.Core tests and a deepseek-v4-flash:cloud think:true MCP operational run.

1 files changed, 3 insertions, 5 deletions

diff --git a/src/Agent.Core/Runtime/PlannerService.cs b/src/Agent.Core/Runtime/PlannerService.cs
index bc96ec7..3591259 100644
--- a/src/Agent.Core/Runtime/PlannerService.cs
+++ b/src/Agent.Core/Runtime/PlannerService.cs
@@ -218,8 +218,7 @@ public sealed class PlannerService(IOllamaClient ollama, AgentRuntimeSettings se
             OllamaResult? result = null;
             try
             {
-                bool? thinkOverride = attempt == 0 ? null : false;
-                result = await _ollama.ChatStructuredAsync(attemptMessages, temperature, formatDoc.RootElement.Clone(), thinkOverride, cancellationToken).ConfigureAwait(false);
+                result = await _ollama.ChatStructuredAsync(attemptMessages, temperature, formatDoc.RootElement.Clone(), null, cancellationToken).ConfigureAwait(false);
                 if (!TryParseSelectedSkills(result.Content, out IReadOnlyList<AgentSkill> selected))
                     throw new PlannerValidationException("Ollama returned an invalid skill selection object.");
                 observeAttempt?.Invoke("skill_selection", attemptMessages, result, null);
@@ -250,8 +249,7 @@ public sealed class PlannerService(IOllamaClient ollama, AgentRuntimeSettings se
             OllamaResult? result = null;
             try
             {
-                bool? thinkOverride = attempt == 0 ? null : false;
-                result = await _ollama.ChatStructuredAsync(attemptMessages, temperature, PlanSchema.Element, thinkOverride, cancellationToken).ConfigureAwait(false);
+                result = await _ollama.ChatStructuredAsync(attemptMessages, temperature, PlanSchema.Element, null, cancellationToken).ConfigureAwait(false);
                 PlanResult? plan = ParsePlan(result.Content);
                 if (plan is null || plan.Tasks.Count == 0)
                     throw new PlannerValidationException("Ollama returned an empty or invalid structured plan.");
@@ -274,7 +272,7 @@ public sealed class PlannerService(IOllamaClient ollama, AgentRuntimeSettings se
                 }
             }
         }
-        throw new PlannerValidationException($"Structured {phase} failed after think=false retry: {lastFailure?.Message}");
+        throw new PlannerValidationException($"Structured {phase} failed after one corrected retry: {lastFailure?.Message}");
     }
 
     private bool TryParseSelectedSkills(string content, out IReadOnlyList<AgentSkill> selected)