added guide on release notes

docs/src/content/docs/case-studies/release-notes.mdx

@@ -0,0 +1,86 @@
+---
+title: Release Notes
+sidebar:
+    order: 7
+---
+import { Code } from '@astrojs/starlight/components';
+import scriptSrc from "../../../../../packages/sample/genaisrc/git-release-notes.genai?raw"
+
+There are plenty of automated `release notes` generator
+that inspect the list of commits since the last release and generate a list of changes.
+The release notes are typically exclusively based on the commit messages.
+
+In the GenAIScript projet, we create a release notes generator **that uses 
+both commit history and the diff of the changes**.
+
+You can see one of the first prototype generated 
+release notes for [v1.41.6](https://github.com/microsoft/genaiscript/releases/tag/1.41.6).
+
+```markdown wrap
+We are excited to announce the release of GenAIScript 1.41.6! 🎉
+
+In this release, we've made some significant improvements to enhance your experience. Here are the key changes:
+
+Improved Release Script: We've fine-tuned our release script to ensure smoother and more efficient releases in the future. 🛠️
+...
+
+```
+
+## Commit history and diff
+
+We start our script by calling `git` a few times to retreive the previous release tag,
+the list of commits, the diff since the tag. 
+(This magic was mostly found using a GitHub Copilot Chat session).
+
+```js title="git-release-notes.genai.js" wrap
+const { stdout: tag } = await host.exec("git", ["describe", "--tags", "--abbrev=0", "HEAD^",])
+const { stdout: commits } = await host.exec("git", ["log", `HEAD...${tag}`,])
+const { stdout: diff } = await host.exec("git", ["diff", `${tag}..HEAD`,])
+```
+
+We use the `def` function with `maxTokens` to inline this information without exceeding the content window
+of the model (32k input).
+
+```js title="git-release-notes.genai.js" wrap
+def("COMMITS", commits, { maxTokens: 4000 })
+def("DIFF", diff, { maxTokens: 20000 })
+```
+
+## Role and task
+
+The rest of the script follows a typical pattern with a role and a task.
+
+```js wrap
+$`
+You are an expert software developer and release manager.
+
+## Task
+
+Generate a clear, exciting, relevant, useful release notes
+for the upcoming release. 
+
+- The commits in the release are in COMMITS.
+- The diff of the changes are in DIFF.
+`
+```
+
+
+## The script
+
+The full script as it is running in GenAIScript is as follows:
+
+<Code code={scriptSrc} wrap={true} lang="js" title="git-release-notes.genai.js" />
+
+## Release-it integration
+
+GenAIScript uses [release-it](https://github.com/release-it/release-it)
+to automate the release process. We configured release-it to run the script using the [cli](/genaiscript/reference/cli)
+ by adding a `github.releaseNotes` field in the `release-it` configuration.
+
+```json title="package.json" wrap
+ "release-it": {
+     "github": {
+         "releaseNotes": "npx --yes genaiscript run git-release-notes"
+     }
+ }
+```

packages/sample/genaisrc/git-release-notes.genai.js

@@ -31,17 +31,19 @@ const { stdout: diff } = await host.exec("git", [
     ":!yarn.lock",
 ])
 
-def("COMMITS", commits, { maxTokens: 4000 })
-def("DIFF", diff, { maxTokens: 20000 })
+const commitsName = def("COMMITS", commits, { maxTokens: 4000 })
+const diffName = def("DIFF", diff, { maxTokens: 20000 })
 
 $`
 You are an expert software developer and release manager.
 
 ## Task
 
 Generate a clear, exciting, relevant, useful release notes
-for the upcoming release ${version} of ${product} on GitHub. The commits in the release are in COMMITS.
-The diff of the changes are in DIFF.
+for the upcoming release ${version} of ${product} on GitHub. 
+
+- The commits in the release are in ${commitsName}.
+- The diff of the changes are in ${diffName}.
 
 ## Guidelines