[8.x] [Obs AI Assistant] Improve instructions for the summarize funct…

…ion (elastic#212936) (elastic#213001)

# Backport

This will backport the following commits from `main` to `8.x`:
- [[Obs AI Assistant] Improve instructions for the summarize function
(elastic#212936)](elastic#212936)

<!--- Backport version: 9.6.6 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sorenlouv/backport)

<!--BACKPORT [{"author":{"name":"Viduni
Wickramarachchi","email":"viduni.wickramarachchi@elastic.co"},"sourceCommit":{"committedDate":"2025-03-03T23:56:55Z","message":"[Obs
AI Assistant] Improve instructions for the summarize function
(elastic#212936)","sha":"ec127e271c5dd23f3c6c11eb410d478030cfb486","branchLabelMapping":{"^v9.1.0$":"main","^v8.19.0$":"8.x","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["release_note:fix","v9.0.0","Team:Obs
AI
Assistant","backport:version","v8.18.0","v9.1.0","v8.19.0"],"title":"[Obs
AI Assistant] Improve instructions for the summarize
function","number":212936,"url":"https://github.com/elastic/kibana/pull/212936","mergeCommit":{"message":"[Obs
AI Assistant] Improve instructions for the summarize function
(elastic#212936)","sha":"ec127e271c5dd23f3c6c11eb410d478030cfb486"}},"sourceBranch":"main","suggestedTargetBranches":["9.0","8.18","8.x"],"targetPullRequestStates":[{"branch":"9.0","label":"v9.0.0","branchLabelMappingKey":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"},{"branch":"8.18","label":"v8.18.0","branchLabelMappingKey":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"},{"branch":"main","label":"v9.1.0","branchLabelMappingKey":"^v9.1.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/212936","number":212936,"mergeCommit":{"message":"[Obs
AI Assistant] Improve instructions for the summarize function
(elastic#212936)","sha":"ec127e271c5dd23f3c6c11eb410d478030cfb486"}},{"branch":"8.x","label":"v8.19.0","branchLabelMappingKey":"^v8.19.0$","isSourceBranch":false,"state":"NOT_CREATED"}]}]
BACKPORT-->

Co-authored-by: Viduni Wickramarachchi <viduni.wickramarachchi@elastic.co>

x-pack/platform/plugins/shared/observability_ai_assistant/server/functions/index.ts

@@ -112,7 +112,7 @@ export const registerFunctions: RegistrationCallback = async ({
     if (isKnowledgeBaseReady) {
       if (availableFunctionNames.includes(SUMMARIZE_FUNCTION_NAME)) {
         instructions.push(`You can use the "${SUMMARIZE_FUNCTION_NAME}" function to store new information you have learned in a knowledge database.
-          Only use this function when the user asks for it.
+          Only use this function when the user asks to remember or store some information.
           All summaries MUST be created in English, even if the conversation was carried out in a different language.`);
       }