> ## Documentation Index
> Fetch the complete documentation index at: https://docs.instructorphp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# V1.20.0

## Breaking Changes

### Renames

* `ReverbAgentEventAdapter` → `AgentEventEnvelopeAdapter`
* `ToolRegistryContract` → `ToolRegistryInterface`
* `DeterministicDriver` → `DeterministicAgentDriver`

## Agent

* `AgentState` now implements `CanMarkExecutionStarted`, `CanMarkStepStarted`, `CanTrackExecutionTime`
* Added `AgentState::recordStep()`, `AgentState::failWith()`, `AgentState::withAddedExecutionTime()`
* `Agent::applyStep()` and `Agent::handleError()` delegate to `AgentState` methods

## StepByStep / Continuation

* New `CanProvideStopReason` interface for criteria to provide explicit stop reasons
* All continuation criteria implement `CanProvideStopReason`:
  * `StepsLimit` → `StopReason::StepsLimitReached`
  * `TokenUsageLimit` → `StopReason::TokenLimitReached`
  * `ExecutionTimeLimit`, `CumulativeExecutionTimeLimit` → `StopReason::TimeLimitReached`
  * `ErrorPolicyCriterion` → `StopReason::ErrorForbade`
  * `FinishReasonCheck` → `StopReason::FinishReasonReceived`
  * `ErrorPresenceCheck`, `RetryLimit` → `StopReason::GuardForbade`
* `ContinuationEvaluation` includes `stopReason` field
* Removed `ContinuationCriteria::inferStopReason()` (stop reasons now come from criteria directly)
* New state contracts: `CanMarkExecutionStarted`, `CanMarkStepStarted`, `CanTrackExecutionTime`

## Command Builders (agent-ctrl)

`ClaudeCommandBuilder`, `CodexCommandBuilder`, `OpenCodeCommandBuilder`:

* `stdbuf -o0` prefix now conditional (checks availability)
* Skipped on Windows
* Skipped when `stdbuf` not found on PATH (fixes macOS)
* Override via `COGNESY_STDBUF` env var: `0` = disable, `1` = force

## Polyglot / Inference

* `InferenceExecution::usage()`: fixed double-counting of current attempt
* `InferenceResponse`: added `<think>...</think>` tag parsing for reasoning content fallback
* New `ReasoningContentSplit` data class
* `AnthropicBodyFormat`: cache marking applies only to last message in sequence (was all messages)
* `DeepseekResponseAdapter`: supports `reasoning`, `analysis` fields as alternatives to `reasoning_content`
* `Inference::with()`: parameters now nullable (pass `null` to skip, was required empty values)
* `PendingInference::asJson()`, `asJsonData()`: use proper JSON extraction with output mode

## HTTP Client

* `CurlHandle::close()`: removed `curl_close()` call (no-op since PHP 8.0, deprecated in PHP 8.5)

## Instructor

* `StructuredOutputStream`: fixed execution reference update during streaming to capture accumulated usage