Anthropic publishes long-running agent harness playbook
Anthropic’s November 26, 2025 engineering post explains why long-running coding agents fail across context windows and proposes a two-agent harness (initializer plus coding agent) that preserves continuity with artifacts like `init.sh`, feature lists, progress logs, and git commits. The guidance is grounded in Claude Agent SDK and Claude Code workflows, arguing that execution structure matters more than adding tools blindly.
Harness engineering is becoming the real moat: better session design can outperform model-only upgrades on long, branching tasks.
- –Breaking work into small feature increments helps avoid one-shot builds that collapse mid-context.
- –Persistent handoff artifacts (progress file, feature JSON, git history) let new sessions recover state fast.
- –Session discipline (run `init.sh`, verify core flows, then implement) catches regressions before new code piles on.
- –External community projects and plugins are already operationalizing Anthropic’s pattern, which suggests broad practical demand.
DISCOVERED
71d ago
2026-03-17
PUBLISHED
71d ago
2026-03-17
RELEVANCE
AUTHOR
Prompt Engineering