agents: forbid compatibility logic for older Bazel versions

.agents/rules/rules_python.md

@@ -15,3 +15,9 @@ description: rules_python-specific Bzlmod, PyPI, and rule usage invariants
   analysis when `<pkg>` is absent from their `pip.parse()` lockfiles. Package
   names in `pip.dep(name = "...")` are normalized (hyphens and underscores map
   to the same name).
+
+## Minimum Supported Bazel Version
+* `//:version.bzl` defines `MINIMUM_BAZEL_VERSION`. Do not add compatibility
+  logic, feature guards, or comments for older Bazel versions.
+* When guarding a feature added after `MINIMUM_BAZEL_VERSION`, verify and
+  comment the exact Bazel version that introduced it.

.agents/skills/review-code/SKILL.md

@@ -65,10 +65,9 @@ file from `.agents/skills/review-code/`:
 8. **`rules_python` Usage Sub-Agent** (`Role: "rules_python Usage Auditor"`):
    - Prompt file:
      `.agents/skills/review-code/review-rules-python-prompt.md`
-   - Focus: Audits changes against `.agents/rules/rules_python.md` and
-     `rules_python`-specific Bzlmod and rule usage invariants (e.g., `pip.dep()`
-     declarations in `MODULE.bazel` for `@pypi//<pkg>` references under
-     `python/**`).
+   - Focus: Audits changes against `.agents/rules/rules_python.md` (e.g.,
+     `pip.dep()` declarations in `MODULE.bazel` and `MINIMUM_BAZEL_VERSION`
+     bounds).
 
 9. **News Entry Sub-Agent** (`Role: "News Entry Auditor"`):
    - Prompt file:

.agents/skills/review-code/review-rules-python-prompt.md

@@ -1,12 +1,15 @@
 You are a specialized `rules_python` Usage Auditor sub-agent.
 Your sole task is to audit all changes in `git diff` against `rules_python`
-Bzlmod and rule usage invariants:
+Bzlmod, Bazel version support, and rule usage invariants:
 
-1. Read and strictly enforce `.agents/rules/rules_python.md` and `AGENTS.md`.
+1. Read and strictly enforce `.agents/rules/rules_python.md`, `version.bzl`, and
+   `AGENTS.md`.
 2. Verify that every `@pypi//<pkg>` target referenced by non-test rules,
    macros, or `BUILD` files under `python/**` (including default attribute
    values and `alias` targets) has a corresponding `pip.dep(name = "<pkg>")`
    declaration on the non-dev `pip` extension in `MODULE.bazel` (with `"pypi"`
    in `use_repo(pip, ...)`).
+3. Verify no compatibility logic, feature guards, or comments target Bazel
+   versions older than `MINIMUM_BAZEL_VERSION` in `//:version.bzl`.
 
 @.agents/skills/review-code/review-report-format.md

.agents/skills/review-code/review-starlark-prompt.md

@@ -19,5 +19,7 @@ in `git diff` against the project's Starlark coding rules and conventions:
 9. Verify `config_setting` names start with `is_` (or `_is_` when private).
 10. Verify non-obvious workarounds have comments stating the intent, why the
     direct approach fails, and why the workaround works.
+11. Verify no compatibility logic or feature guards target Bazel versions
+    older than `MINIMUM_BAZEL_VERSION` in `//:version.bzl`.
 
 @.agents/skills/review-code/review-report-format.md

AGENTS.md

@@ -174,6 +174,9 @@ This repository contains 3 Bazel bzlmod modules.
 public API. DO NOT add, remove, or modify these build flags unless specifically
 instructed to.
 
+`version.bzl` defines `MINIMUM_BAZEL_VERSION`. Do not add compatibility logic
+or feature guards for Bazel versions older than `MINIMUM_BAZEL_VERSION`.
+
 `bazel query --output=build` can be used to inspect target definitions.
 
 In WORKSPACE mode: