feat: agent loop harness with Claude Code plugin support

Generator-evaluator architecture with iterative context-reset for long-running coding tasks. Ships as a Claude Code plugin — install with /plugin and use /agent-loop:init, /agent-loop:plan, /agent-loop:run.
2026-03-27 08:03:18 -04:00
commit 17e5eb707f
29 changed files with 2546 additions and 0 deletions
--- a/lib/prompt.sh
+++ b/lib/prompt.sh
@@ -0,0 +1,95 @@
+#!/bin/bash
+# Prompt assembly — composes the final prompt from base + mode overlay.
+# Injects runtime variables (scope budgets, current story, iteration count).
+
+# Build the complete prompt for a given agent role and mode.
+# Usage: build_prompt "generator" "implement"
+#        build_prompt "evaluator" "implement"
+build_prompt() {
+    local role="$1"    # generator | evaluator
+    local mode="$2"    # implement | explore | fix
+
+    local base_file="$LOOP_DIR/prompts/${role}/_base.md"
+    local mode_file="$LOOP_DIR/prompts/${role}/${mode}.md"
+
+    local prompt=""
+
+    # Start with base prompt
+    if [ -f "$base_file" ]; then
+        prompt=$(cat "$base_file")
+    else
+        log "WARNING: Missing base prompt: $base_file"
+        return 1
+    fi
+
+    # Append mode-specific overlay
+    if [ -f "$mode_file" ]; then
+        prompt="${prompt}
+
+---
+
+$(cat "$mode_file")"
+    else
+        log "WARNING: Missing mode prompt: $mode_file"
+    fi
+
+    # Inject runtime variables
+    prompt=$(inject_variables "$prompt" "$mode")
+
+    printf '%s\n' "$prompt"
+}
+
+# Replace template variables in prompt text
+inject_variables() {
+    local text="$1"
+    local mode="$2"
+
+    # Scope budgets from config
+    local max_read max_write max_modify
+    max_read=$(get_config_value ".scopeBudgets.${mode}.maxFilesToRead" "50")
+    max_write=$(get_config_value ".scopeBudgets.${mode}.maxLinesToWrite" "500")
+    max_modify=$(get_config_value ".scopeBudgets.${mode}.maxFilesToModify" "10")
+
+    text="${text//\{\{MAX_FILES_TO_READ\}\}/$max_read}"
+    text="${text//\{\{MAX_LINES_TO_WRITE\}\}/$max_write}"
+    text="${text//\{\{MAX_FILES_TO_MODIFY\}\}/$max_modify}"
+    text="${text//\{\{MODE\}\}/$mode}"
+    text="${text//\{\{ITERATION\}\}/$ITERATION}"
+    text="${text//\{\{MAX_ITERATIONS\}\}/$MAX_ITERATIONS}"
+    text="${text//\{\{LOOP_DIR\}\}/$LOOP_DIR}"
+    text="${text//\{\{PROJECT_ROOT\}\}/$PROJECT_ROOT}"
+    text="${text//\{\{CURRENT_STORY_ID\}\}/${CURRENT_STORY_ID:-unknown}}"
+    text="${text//\{\{PRE_GENERATOR_SHA\}\}/${PRE_GENERATOR_SHA:-HEAD~1}}"
+
+    printf '%s\n' "$text"
+}
+
+# Read a value from config.json with a default fallback
+get_config_value() {
+    local path="$1"
+    local default="$2"
+    local config="$LOOP_DIR/config.json"
+
+    [ -f "$config" ] || { echo "$default"; return; }
+
+    if command -v jq &>/dev/null; then
+        local val
+        val=$(jq -r "$path // empty" "$config" 2>/dev/null)
+        echo "${val:-$default}"
+    else
+        LOOP_CONFIG="$config" LOOP_PATH="$path" LOOP_DEFAULT="$default" python3 -c "
+import json, os
+d = json.load(open(os.environ['LOOP_CONFIG']))
+keys = os.environ['LOOP_PATH'].lstrip('.').split('.')
+for k in keys:
+    d = d.get(k) if isinstance(d, dict) else None
+    if d is None:
+        break
+val = d if d is not None and d != {} else os.environ['LOOP_DEFAULT']
+# Normalize Python booleans to lowercase for shell compatibility
+if isinstance(val, bool):
+    val = str(val).lower()
+print(val, end='')
+"
+    fi
+}