YT · YOUTUBE// 25d agoTUTORIAL

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.

// ANALYSIS

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.

// TAGS

claude-codeagentai-codingprompt-engineeringtestingdevtool

DISCOVERED

25d ago

2026-03-17

PUBLISHED

25d ago

2026-03-17

RELEVANCE

8/ 10

AUTHOR

Prompt Engineering