You're adding comprehensive tests to a legacy service in phases. In phase one, a subagent mapped the module structure and identified the high-risk billing paths. In phase two you spawn new subagents to write tests for each area, but they repeat the structural exploration and sometimes target low-impact code. What change best fixes this?

Answer: C — Summarize the key findings from phase one, including module map, high-risk paths, and priorities, and inject that summary into each phase-two subagent's initial prompt.

Subagents don't inherit context automatically, so summarizing one phase's key findings and injecting the summary into the next phase's subagents gives them what they need without repeating exploration (task 5.4). No setting gives subagents another agent's transcript by default (a). That's the isolated-context misconception, and a raw transcript would be verbose anyway. Merging everything into one long subagent (b) brings back context exhaustion and degradation. Writing tests from function names only (d) gives up the understanding needed for meaningful tests.