feat: lenient JSON repair for pasted MCP snippets

Pasted config snippets no longer have to be valid JSON. repair_json_text()
auto-fixes markdown fences, surrounding prose, // /* */ # comments,
trailing and missing commas, smart quotes, single quotes, unquoted keys,
Python/JS literals, and unclosed braces. parse_pasted_json_verbose()
reports every repair applied; the paste dialog now parses as you type
and previews exactly what will be added and what was fixed.

Also includes ruff lint fixes and formatting across bcc.py/bcc_core.py.

tests/test_json_repair.py

@@ -0,0 +1,188 @@
+"""Tests for the lenient JSON repair pipeline (repair_json_text +
+parse_pasted_json_verbose). Every case here is a shape people actually paste
+from MCP docs, blog posts, and chat windows."""
+
+import pytest
+
+import bcc_core as c
+
+GOOD = {"command": "npx", "args": ["-y", "@x/brave"]}
+
+
+def assert_brave(servers):
+    assert "brave" in servers
+    assert servers["brave"]["command"] == "npx"
+
+
+# --------------------------------------------------------------------------- #
+# Valid JSON passes through untouched
+# --------------------------------------------------------------------------- #
+def test_strict_json_no_notes():
+    servers, notes = c.parse_pasted_json_verbose('{"brave": {"command": "npx", "args": []}}')
+    assert_brave(servers)
+    assert notes == []
+
+
+# --------------------------------------------------------------------------- #
+# Markdown / prose wrappers
+# --------------------------------------------------------------------------- #
+def test_markdown_fence():
+    text = 'Add this to your config:\n```json\n{"brave": {"command": "npx"}}\n```\nThen restart.'
+    servers, notes = c.parse_pasted_json_verbose(text)
+    assert_brave(servers)
+    assert any("fence" in n for n in notes)
+
+
+def test_fence_without_language_tag():
+    text = '```\n{"brave": {"command": "npx"}}\n```'
+    servers, _ = c.parse_pasted_json_verbose(text)
+    assert_brave(servers)
+
+
+def test_prose_around_bare_json():
+    text = 'Paste the following: {"brave": {"command": "npx"}} and restart Claude.'
+    servers, notes = c.parse_pasted_json_verbose(text)
+    assert_brave(servers)
+    assert any("before" in n or "after" in n for n in notes)
+
+
+# --------------------------------------------------------------------------- #
+# Comments
+# --------------------------------------------------------------------------- #
+def test_line_comments():
+    text = '{\n  // the search server\n  "brave": {"command": "npx"}\n}'
+    servers, notes = c.parse_pasted_json_verbose(text)
+    assert_brave(servers)
+    assert any("//" in n for n in notes)
+
+
+def test_block_comments():
+    text = '{ /* config */ "brave": {"command": "npx"} }'
+    servers, _ = c.parse_pasted_json_verbose(text)
+    assert_brave(servers)
+
+
+def test_url_with_double_slash_is_not_a_comment():
+    text = '{"remote": {"url": "https://mcp.example.com/sse"}}'
+    servers, notes = c.parse_pasted_json_verbose(text)
+    assert servers["remote"]["url"] == "https://mcp.example.com/sse"
+    assert notes == []
+
+
+# --------------------------------------------------------------------------- #
+# Commas
+# --------------------------------------------------------------------------- #
+def test_trailing_comma_object():
+    text = '{"brave": {"command": "npx", "args": ["-y"],},}'
+    servers, notes = c.parse_pasted_json_verbose(text)
+    assert_brave(servers)
+    assert any("trailing" in n for n in notes)
+
+
+def test_missing_comma_between_servers():
+    text = '{"brave": {"command": "npx"}\n"git": {"command": "uvx"}}'
+    servers, notes = c.parse_pasted_json_verbose(text)
+    assert "brave" in servers and "git" in servers
+    assert any("missing comma" in n for n in notes)
+
+
+def test_missing_comma_between_string_fields():
+    text = '{"brave": {"command": "npx"\n"args": ["-y"]}}'
+    servers, _ = c.parse_pasted_json_verbose(text)
+    assert servers["brave"]["args"] == ["-y"]
+
+
+# --------------------------------------------------------------------------- #
+# Quotes
+# --------------------------------------------------------------------------- #
+def test_smart_quotes():
+    text = "{“brave”: {“command”: “npx”}}"
+    servers, notes = c.parse_pasted_json_verbose(text)
+    assert_brave(servers)
+    assert any("smart quotes" in n for n in notes)
+
+
+def test_single_quotes():
+    text = "{'brave': {'command': 'npx', 'args': ['-y']}}"
+    servers, notes = c.parse_pasted_json_verbose(text)
+    assert_brave(servers)
+    assert any("single-quoted" in n for n in notes)
+
+
+def test_single_quotes_with_inner_double():
+    text = """{'brave': {'command': 'npx', 'env': {'NOTE': 'say "hi"'}}}"""
+    servers, _ = c.parse_pasted_json_verbose(text)
+    assert servers["brave"]["env"]["NOTE"] == 'say "hi"'
+
+
+# --------------------------------------------------------------------------- #
+# JS-style laxness
+# --------------------------------------------------------------------------- #
+def test_unquoted_keys():
+    text = '{brave: {command: "npx", args: ["-y"]}}'
+    servers, notes = c.parse_pasted_json_verbose(text)
+    assert_brave(servers)
+    assert any("bare object keys" in n for n in notes)
+
+
+def test_python_literals():
+    text = '{"brave": {"command": "npx", "enabled": True, "extra": None}}'
+    servers, notes = c.parse_pasted_json_verbose(text)
+    assert servers["brave"]["enabled"] is True
+    assert servers["brave"]["extra"] is None
+    assert any("literals" in n for n in notes)
+
+
+# --------------------------------------------------------------------------- #
+# Structure damage
+# --------------------------------------------------------------------------- #
+def test_braceless_fragment():
+    text = '"brave": {"command": "npx", "args": ["-y"]}'
+    servers, notes = c.parse_pasted_json_verbose(text)
+    assert_brave(servers)
+    assert any("wrapped" in n for n in notes)
+
+
+def test_missing_closing_braces():
+    text = '{"mcpServers": {"brave": {"command": "npx", "args": ["-y"]'
+    servers, notes = c.parse_pasted_json_verbose(text)
+    assert_brave(servers)
+    assert any("unclosed" in n for n in notes)
+
+
+def test_kitchen_sink():
+    # fence + comment + single quotes + unquoted key + trailing comma + prose
+    text = (
+        "Here's the config you need:\n"
+        "```json\n"
+        "{\n"
+        "  // brave search\n"
+        "  brave: {\n"
+        "    'command': 'npx',\n"
+        "    'args': ['-y', '@x/brave',],\n"
+        "  },\n"
+        "}\n"
+        "```\n"
+    )
+    servers, notes = c.parse_pasted_json_verbose(text)
+    assert_brave(servers)
+    assert servers["brave"]["args"] == ["-y", "@x/brave"]
+    assert len(notes) >= 4
+
+
+# --------------------------------------------------------------------------- #
+# Still fails cleanly on hopeless input
+# --------------------------------------------------------------------------- #
+def test_hopeless_input_raises_value_error():
+    with pytest.raises(ValueError):
+        c.parse_pasted_json_verbose("this is just prose with no json at all")
+
+
+def test_junk_object_still_rejected():
+    with pytest.raises(ValueError):
+        c.parse_pasted_json_verbose('{"junk": 5}')
+
+
+def test_empty_raises():
+    with pytest.raises(ValueError):
+        c.parse_pasted_json_verbose("   ")