feat: deliver v1.8.0 harness reliability and parity updates

skills/agent-harness-construction/SKILL.md

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+---
+name: agent-harness-construction
+description: Design and optimize AI agent action spaces, tool definitions, and observation formatting for higher completion rates.
+origin: ECC
+---
+
+# Agent Harness Construction
+
+Use this skill when you are improving how an agent plans, calls tools, recovers from errors, and converges on completion.
+
+## Core Model
+
+Agent output quality is constrained by:
+1. Action space quality
+2. Observation quality
+3. Recovery quality
+4. Context budget quality
+
+## Action Space Design
+
+1. Use stable, explicit tool names.
+2. Keep inputs schema-first and narrow.
+3. Return deterministic output shapes.
+4. Avoid catch-all tools unless isolation is impossible.
+
+## Granularity Rules
+
+- Use micro-tools for high-risk operations (deploy, migration, permissions).
+- Use medium tools for common edit/read/search loops.
+- Use macro-tools only when round-trip overhead is the dominant cost.
+
+## Observation Design
+
+Every tool response should include:
+- `status`: success|warning|error
+- `summary`: one-line result
+- `next_actions`: actionable follow-ups
+- `artifacts`: file paths / IDs
+
+## Error Recovery Contract
+
+For every error path, include:
+- root cause hint
+- safe retry instruction
+- explicit stop condition
+
+## Context Budgeting
+
+1. Keep system prompt minimal and invariant.
+2. Move large guidance into skills loaded on demand.
+3. Prefer references to files over inlining long documents.
+4. Compact at phase boundaries, not arbitrary token thresholds.
+
+## Architecture Pattern Guidance
+
+- ReAct: best for exploratory tasks with uncertain path.
+- Function-calling: best for structured deterministic flows.
+- Hybrid (recommended): ReAct planning + typed tool execution.
+
+## Benchmarking
+
+Track:
+- completion rate
+- retries per task
+- pass@1 and pass@3
+- cost per successful task
+
+## Anti-Patterns
+
+- Too many tools with overlapping semantics.
+- Opaque tool output with no recovery hints.
+- Error-only output without next steps.
+- Context overloading with irrelevant references.