ADR — ACS Failure & Expansion Policy (v0)

Decision

• On provider timeout/errors, do not auto fallback to L1.
• First, retry within per-provider time slice, possibly with reduced top_k.
• If project data is missing/insufficient, emit warning and propose explicit L1 expansion.
• Return structured error to the agent with options; agent decides next step.

Context

• Priorities: Quality > Strict token budget > Latency (comfort).
• Streaming disabled in v0; batch replies.

Consequences

• Predictable token spend; avoids silent scope creep via hidden L1.
• Slightly higher perceived latency in error cases, but transparent control.

Record

• Errors contain: code, message, retriable, attempt/max_attempts, suggested options.
• Provider API adds warnings[]; L1 expansion requires expansion:true.