Phase 7a: Configuration & Platform Primitives

[Wahbeh-Mohammad]

Ship Configuration and the shared platform primitives several earlier phases were about to duplicate.

Scope

• Configuration model + validation (CFG-*), proxy options (ProxyOptions, including the challengeHandler
  slot whose protocol lands in 8a), timeouts, connection settings.
• config/clock.ts — the real injectable Clock/random determinism seam that replaces 5a's ad hoc one.
• config/http-date.ts — shared RFC 1123 parser and formatter; 5a's private parser becomes an import.
• config/retryable.ts — one shared retryable-status definition (408, 429, 5xx except 501/505) so RETRY-1 and
  CFG-35 cannot drift.
• CFG-36 build/runtime descriptor — version via build-time codegen, never a runtime placeholder — plus
  clientIdentityStep() (RECOV-33: Append/Replace token composition, blank-line suppression), closing
  NFR-15.

Spec refs

Product spec §16 (CFG-*), appendix C RECOV-33, NFR-15. sdk-design: §8.

Dependencies

Phases 0–4c. Must run before 5a — 5a Task 8 consumes Clock, and its parser/retryable-status modules are
sourced from here. Leads 7b (OBS-35's log-level resolution wants Configuration).

Docs

• Design: docs/superpowers/specs/2026-07-28-phase7a-configuration-design.md
• Plan: docs/superpowers/plans/2026-07-28-phase7a-configuration.md
• Segmentation: docs/superpowers/specs/2026-07-28-phase7-segmentation-design.md
• Validation prompt: docs/validation-prompts/phase7a-configuration-validation-prompt.md

Notes

clientIdentityStep is not installed by standardResilience() by default — callers install it explicitly.
The User-Agent actually reaching the wire is verified in 8a.