pub const STEP_CTX_KEY: &str = "step_ctx";Expand description
ctx.meta.runtime key that carries the GH #21 Phase 2 Step tier’s
resolved context bundle (TaskSpec.step_ctx, threaded through by
Engine::dispatch_attempt_with on every attempt — same insertion
site as RUN_ID_KEY). Consumed by
crate::middleware::agent_context::AgentContextMiddleware, which
unpacks the bundle’s keys and applies them with the same
only-if-absent mechanics as the Agent / BP-global tiers, ordered
FIRST (Step outranks Agent and BP-global — see that middleware’s
module doc for the full precedence narrative). The bundle itself
(this key’s raw value) stays in the runtime bag verbatim — only its
individual keys are folded into AgentContextView::extra.