Preserve every fetched search source within observation budget

tests/test_search_observation_budget.py

@@ -0,0 +1,37 @@
+from src.clean_agent_preview import preview_tool_result_text
+
+
+def test_all_fetched_sources_survive_observation_budget():
+    sources = '```sources\n' + '\n'.join(
+        f'[{i}] Page {i}\nhttps://example.org/{i}' for i in range(1, 6)
+    ) + '\n```\nQuery: example research\n'
+    report = sources
+    for i in range(1, 6):
+        report += (f'\n[CONTENT {i}] From: https://example.org/{i}\n'
+                   f'Title: Page {i}\n------------------------------\n'
+                   + f'Evidence from page {i}. ' * 200
+                   + '\nTL;DR:\n' + 'Repeated summary. ' * 200)
+    output = preview_tool_result_text({'output': report, 'exit_code': 0}, 'web_search', {})
+    assert len(output) <= 8000
+    for i in range(1, 6):
+        assert f'[CONTENT {i}] From: https://example.org/{i}' in output
+        assert f'Evidence from page {i}.' in output
+    assert 'Repeated summary.' not in output
+    assert 'full details' in output
+
+
+def test_short_search_results_are_unchanged():
+    text = 'No matching sources were found.'
+    assert preview_tool_result_text({'output': text}, 'web_search', {}) == text
+
+
+def test_failure_status_is_not_lost_to_search_compaction():
+    result = {'output': 'Partial evidence. ' * 1000, 'error': 'fetch failed', 'exit_code': 1}
+    output = preview_tool_result_text(result, 'web_search', {})
+    assert 'fetch failed' in output[:100]
+
+
+def test_other_tool_observations_keep_existing_budget():
+    output = preview_tool_result_text({'output': 'x' * 9000}, 'bash', {})
+    assert output.startswith('x' * 8000)
+    assert 'truncated at 8000' in output