## TL;DR
Find the callable named just before the traceback, then give autodoc a parseable signature. Unwrap or annotate the decorator, add an explicit __signature__, or exclude the member. Rebuild and confirm the page renders.

## The exact error
```text
ValueError: invalid signature
```

## Steps
1. **Identify the callable**
   Read the traceback above the ValueError; autodoc names the module and object it was processing when it failed.
   Success check: You have the module path and object name of the failing callable.
2. **Inspect the signature**
   Import the object in a Python shell and call inspect.signature on it. Decorators that hide __wrapped__ and C functions without __text_signature__ are the usual culprits.
   Success check: inspect.signature raises the same ValueError, confirming the source.
3. **Give it a parseable signature**
   For decorated functions, set functools.wraps or assign __wrapped__. For dynamic callables, attach an explicit __signature__ object. As a last resort, exclude the member with :exclude-members:.
   Success check: inspect.signature returns a valid signature and the object imports cleanly.
4. **Rebuild the affected page**
   Run sphinx-build -b html on the project and open the rendered API page.
   Success check: The page renders with the correct parameter list and the build log shows no ValueError.

## When to use
- Use when autodoc dies on ValueError: invalid signature during a docs build.
- Use when an agent generates API reference for a codebase with heavy decorators or C extensions.

## When not to use
- Not for ImportError or ModuleNotFoundError in autodoc (different failure family).
- Not for signature mismatches between docs and code (that is doc drift, not a build crash).

## Why it happens
Autodoc calls inspect.signature on every documented callable. Objects whose signatures are constructed dynamically, hidden by decorators without __wrapped__, or implemented in C without signature metadata make that call raise ValueError, which aborts the page.

## Edge cases
napoleon and autodoc-typehints change how signatures are processed, so a signature that builds under plain autodoc can fail with extensions enabled. Mocking the module with autodoc_mock_imports can hide the real signature; prefer fixing the signature over mocking when the object is importable.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_BROodA3W42dXhQCcqGIjFw