🤖 I have created a release *beep* *boop*
---


##
[0.16.0](hugr-py-v0.15.4...hugr-py-v0.16.0)
(2026-04-01)

This release changes the default text serialization format from JSON to
`MODEL_WITH_EXTS` (the JSON format is now deprecated).
It also adds the ability to link packages and modules from Python,
renders operation type arguments in HUGR visualizations, introduces a
new `debug_info` module for attaching source-level debug metadata to
nodes,
and introduces multi-version support in `ExtensionRegistry`, allowing
different versions of the same extension to coexist in the same
registry.


### ⚠ BREAKING CHANGES

* `ExtensionRegistry` may now contain multiple versions of the same
extension. `.extensions` is now an iterator of the latest versions
instead of a dictionary. `.register_updated` and `.add_extension` have
been replaced with a singular `.register`.
* Default `EnvelopeConfig` changed from `EnvelopeFormat.JSON` to
`EnvelopeFormat.MODEL_WITH_EXTS`.
* Substituted `hugr-py/src/hugr/tys.py::_type_str` with
`hugr-py/src/hugr/utils.py::name_w_args`.

### Features

* Add debug info metadata specification in `hugr-py`
([#2971](#2971))
([a4da8ef](a4da8ef))
* Allow multiple versions of an extension in an ExtensionRegistry
([#3005](#3005))
([ee90cd1](ee90cd1))
* Deprecate JSON serialization format
([#2991](#2991))
([0f7a880](0f7a880))
* Operation parameter rendering in HUGR visualizations
([#2995](#2995))
([d619148](d619148))
* Allow linking packages and modules from Python
([#2947](#2947))
([329c243](329c243))
* Make `_composable_pass` and `_scope` public modules
([#2962](#2962))
([1d6af9a](1d6af9a)),
closes [#2961](#2961)
* Allow missing ext versions ExtensionDesc metadata
([#2979](#2979))
([bc1c445](bc1c445))
* Allow dfg conversion in to TrackedDfg
([#2993](#2993))
([3bd7a88](3bd7a88))


### Bug Fixes

* Allow both _composable_pass and composable_pass imports
([#2965](#2965))
([0a5664d](0a5664d))
* Allow both _scope and scope imports
([#3003](#3003))
([de0458c](de0458c))
* Always do extension resolution when loading packages and hugrs
([#2953](#2953))
([0086d2a](0086d2a))
* Correct pyo3 module definitions and add missing exception class export
([#2964](#2964))
([3df73f4](3df73f4))
* Include extensions during link serialization
([#2992](#2992))
([9236e89](9236e89))
* Prefix names with underscores during serialization
([#2989](#2989))
([8aab636](8aab636))
* Use valid identifiers when constructing AST model
([#2973](#2973))
([8750a6b](8750a6b))

---
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Please](https://github.com/googleapis/release-please). See
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---------

Co-authored-by: Agustín Borgna <[email protected]>