> ## 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.

# V2.8.4

v2.8.4 makes Tell’s programmable runtime and operator boundaries available as
a supported 2.x surface. It also fixes Tell construction with the released
`cognesy/agents` v2.8.3 package when an application supplies its own driver.

## Modular Tell Runtime

Tell now provides a static, host-scoped composition model for applications that
need to configure its runtime before boot. `TellHostBuilder` and the standard
profile assemble typed capabilities without exposing a mutable service
container. The public SDK adds catalogue and direct-tool access, typed
reasoning controls, deterministic testing, controlled cancellation, and a
one-run `tell agent --rpc` protocol for external supervisors.

Project workspaces gain named branches, branch-local secret-free configuration,
and inspectable durable child-agent runs. Shell jobs are confined to an
explicit resource host with bounded output, lifetime, concurrency, approval,
and cleanup behavior.

## Runtime Compatibility and Tooling

Tell now attaches an injected `ToolCallingDriver` after creating its definition
loop. This preserves custom-driver integrations with the published Agents
v2.8.3 constructor contract.

Hub can execute Markdown-backed examples by materializing their PHP fence in a
temporary sibling file, preserving `__DIR__` behavior and cleaning the file up
after execution. Polyglot now advertises reasoning-effort support for matching
DeepSeek V4 and Qwen 3 models.

## Upgrade Notes

Existing Tell facade calls, CLI routes, persisted workspace schemas, and event
envelopes remain compatible. No migration is required. Applications that
provide a custom Tell driver can upgrade directly; the driver is now applied
through the supported `AgentLoop::withDriver()` path.