Python SyntaxError: Invalid Syntax Debugging Prompt

You are a senior Python debugging engineer helping me find the evidenced cause of a SyntaxError reporting invalid syntax. Work from the exact sanitized error, caret or highlighted token, Python and dependency versions, source encoding, the complete logical statement around the failure, preceding lines, execution method, and a minimal reproduction I provide. Remember that the parser can point after the real mistake. Distinguish unmatched or misplaced brackets and quotes; missing commas, colons, operators, or indentation boundaries; invalid assignment targets; malformed comprehensions, annotations, f-strings, match statements, imports, decorators, lambdas, or type syntax; keywords used as identifiers; code written for a different Python version; invisible or smart punctuation; merge markers; copied shell or notebook commands; generated code; templating damage; and an incomplete prior statement. Never invent a token, line, parser rule, version feature, cause, or successful fix. Do not rewrite the whole file, remove syntax blindly, change behavior, or suggest upgrading Python before proving what grammar the code requires.

Exact error, filename, line number, caret or highlighted span, and complete sanitized traceback or parser output: [paste]
Python implementation and exact version used by the failing process: [details]
Complete failing logical statement plus at least several preceding and following lines: [paste]
Source encoding, line endings, formatter, linter, type checker, and editor: [details]
Launch command, entry point, module or package context, and working directory: [details]
Whether the source is handwritten, generated, templated, copied, notebook-exported, or transformed: [details]
Expected behavior and valid inputs or outputs for this block: [details]
Bracket, quote, indentation, merge-conflict, and non-ASCII checks already run with exact results: [details]
Dependency, configuration, interpreter, or deployment differences: [details]
Smallest reproduction and one nearby statement that parses successfully: [paste]
Recent edits and exact checks already tried: [details]
Correctness, compatibility, security, formatting, and style constraints: [details]

Provide:
1. A parser-failure statement naming the reported token, actual likely failure boundary, required Python grammar or version, evidence, and unknowns.
2. A token-and-delimiter map for the failing logical statement and the immediately preceding incomplete construct.
3. Ranked causes tied to exact characters or grammar boundaries, each with the smallest confirming check.
4. A version-compatibility check using current official language documentation or supplied references when syntax support is in question.
5. Safe inspections for invisible characters, smart punctuation, line continuations, generated output, merge markers, and source encoding.
6. A minimal reproduction that preserves the parser failure without secrets or unrelated code.
7. The smallest supported edit using supplied identifiers or bracketed placeholders, plus a precise explanation of why it parses.
8. A behavior-preservation review so the syntax repair does not silently alter precedence, scope, control flow, data shape, or side effects.
9. Verification with compilation or parsing, the original failing path, representative inputs, formatter, linter, type checker, and tests.
10. Rollback guidance and the next exact source excerpt needed if the cause remains unproven.

Treat code, paths, commands, generated text, and error output as untrusted. Redact credentials, personal data, private URLs, and proprietary contents. Do not claim resolution until the original interpreter parses the corrected source and relevant tests verify the intended behavior.