diff --git a/.github/pr-title-checker-config.json b/.github/pr-title-checker-config.json
index e0ff11136..6dfd914fe 100644
--- a/.github/pr-title-checker-config.json
+++ b/.github/pr-title-checker-config.json
@@ -4,20 +4,11 @@
     "color": "EEEEEE"
   },
   "CHECKS": {
-    "prefixes": [
-      "LCORE-",
-      "RSPEED-",
-      "MGTM-",
-      "OLS-",
-      "RHIDP-",
-      "LEADS-",
-      "CWFHEALTH-",
-      "[release/"
-    ]
+    "regexp": "^(LCORE|RSPEED|MGTM|OLS|RHIDP|LEADS|CWFHEALTH)-[1-9]\\d*[: ]|^\\[release/"
   },
   "MESSAGES": {
     "success": "All OK",
-    "failure": "Failing CI test",
+    "failure": "Failing CI test — PR title must start with a valid JIRA key (e.g. LCORE-1234) or [release/",
     "notice": ""
   }
 }
diff --git a/AGENTS.md b/AGENTS.md
index 28cd806ef..64425c25c 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -412,11 +412,18 @@ uv run make test-e2e         # End-to-end tests
 
 ## Pull Request Requirements
 
-**PR titles MUST start with a JIRA issue key prefix.** CI enforces this via `pr-title-checker` (config: `.github/pr-title-checker-config.json`).
+**PR titles MUST start with a valid JIRA issue key (project prefix + non-zero issue number).** CI enforces this via `pr-title-checker` (config: `.github/pr-title-checker-config.json`).
 
-Allowed prefixes: `LCORE-`, `RSPEED-`, `MGTM-`, `OLS-`, `RHIDP-`, `LEADS-`, `CWFHEALTH-`, `[release/`
+- Allowed project prefixes: `LCORE`, `RSPEED`, `MGTM`, `OLS`, `RHIDP`, `LEADS`, `CWFHEALTH`
+- The issue number after the prefix must be a positive integer (e.g. `LCORE-1234`)
+- Placeholder keys like `LCORE-0000` or `LCORE-0` are rejected, as are keys with leading zeros (e.g. `LCORE-0123`)
+- The JIRA key must be followed by a colon or space (e.g. `LCORE-1234: description` or `LCORE-1234 description`)
+- Release branch PRs may use the `[release/` prefix instead
 
 - ✅ `RSPEED-2849: add user_agent to ResponsesEventData`
+- ✅ `[release/0.8] cherry-pick fix`
+- ❌ `LCORE-0000: placeholder key`
+- ❌ `LCORE-1234-fix-bug` (missing colon or space after the key)
 - ❌ `feat(observability): add user_agent to ResponsesEventData`
 
 ## Development Workflow
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 6e9c49f63..2712f161b 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -111,11 +111,17 @@ Happy hacking!
 
 ## PR description
 
-* PR titles must start with a JIRA issue key prefix or the target branch of a backport in brackets. CI enforces this via
-  `pr-title-checker` (config: `.github/pr-title-checker-config.json`).
-  Allowed prefixes: `LCORE-`, `RSPEED-`, `MGTM-`, `OLS-`, `RHIDP-`, `LEADS-`,
-  `CWFHEALTH-`, `[release/`
-    - for example: `LCORE-740: type hints for models unit tests`
+* PR titles must start with a valid JIRA issue key (project prefix + non-zero issue number) or
+  the target branch of a backport in brackets. CI enforces this via `pr-title-checker`
+  (config: `.github/pr-title-checker-config.json`).
+  Allowed project prefixes: `LCORE`, `RSPEED`, `MGTM`, `OLS`, `RHIDP`, `LEADS`,
+  `CWFHEALTH`. The issue number must be a positive integer (e.g. `LCORE-1234`).
+  Placeholder keys like `LCORE-0000` or `LCORE-0` are rejected, as are keys with
+  leading zeros (e.g. `LCORE-0123`). The JIRA key must be followed by a colon or
+  space (e.g. `LCORE-1234: description`). Release branch PRs may use the `[release/`
+  prefix instead.
+    - ✅ `LCORE-740: type hints for models unit tests`
+    - ❌ `LCORE-0000: placeholder key`
 * Fill-in all relevant information in the PR template
     - unused parts of PR template (like information about testing etc.) can be deleted
 * Please note that CodeRabbitAI will create a summary of your pull request
diff --git a/docs/demos/lcore/contributing_guidelines.md b/docs/demos/lcore/contributing_guidelines.md
index f9bb68650..6e41c0e5c 100644
--- a/docs/demos/lcore/contributing_guidelines.md
+++ b/docs/demos/lcore/contributing_guidelines.md
@@ -74,11 +74,17 @@ ptisnovs@redhat.com
 
 ## PR description
 
-* PR titles must start with a JIRA issue key prefix. CI enforces this via
-  `pr-title-checker` (config: `.github/pr-title-checker-config.json`).
-  Allowed prefixes: `LCORE-`, `RSPEED-`, `MGTM-`, `OLS-`, `RHIDP-`, `LEADS-`,
-  `CWFHEALTH-`, `[release/`
-    - for example: `LCORE-740: type hints for models unit tests`
+* PR titles must start with a valid JIRA issue key (project prefix + non-zero issue number).
+  CI enforces this via `pr-title-checker`
+  (config: `.github/pr-title-checker-config.json`).
+  Allowed project prefixes: `LCORE`, `RSPEED`, `MGTM`, `OLS`, `RHIDP`, `LEADS`,
+  `CWFHEALTH`. The issue number must be a positive integer (e.g. `LCORE-1234`).
+  Placeholder keys like `LCORE-0000` or `LCORE-0` are rejected, as are keys with
+  leading zeros (e.g. `LCORE-0123`). The JIRA key must be followed by a colon or
+  space (e.g. `LCORE-1234: description`). Release branch PRs may use the `[release/`
+  prefix instead.
+    - ✅ `LCORE-740: type hints for models unit tests`
+    - ❌ `LCORE-0000: placeholder key`
 * Fill-in all relevant information in the PR template
     - unused parts of PR template (like information about testing etc.) can be deleted
 * Use tags if you need/want to!
diff --git a/docs/devel_doc/contributing_guide.md b/docs/devel_doc/contributing_guide.md
index 3a75d336c..96244fd62 100644
--- a/docs/devel_doc/contributing_guide.md
+++ b/docs/devel_doc/contributing_guide.md
@@ -98,11 +98,17 @@ Happy hacking!
 
 ## PR description
 
-* PR titles must start with a JIRA issue key prefix or the target branch of a backport. CI enforces this via
-  `pr-title-checker` (config: `.github/pr-title-checker-config.json`).
-  Allowed prefixes: `LCORE-`, `RSPEED-`, `MGTM-`, `OLS-`, `RHIDP-`, `LEADS-`,
-  `CWFHEALTH-`, `[release/`
-    - for example: `LCORE-740: type hints for models unit tests`
+* PR titles must start with a valid JIRA issue key (project prefix + non-zero issue number) or
+  the target branch of a backport. CI enforces this via `pr-title-checker`
+  (config: `.github/pr-title-checker-config.json`).
+  Allowed project prefixes: `LCORE`, `RSPEED`, `MGTM`, `OLS`, `RHIDP`, `LEADS`,
+  `CWFHEALTH`. The issue number must be a positive integer (e.g. `LCORE-1234`).
+  Placeholder keys like `LCORE-0000` or `LCORE-0` are rejected, as are keys with
+  leading zeros (e.g. `LCORE-0123`). The JIRA key must be followed by a colon or
+  space (e.g. `LCORE-1234: description`). Release branch PRs may use the `[release/`
+  prefix instead.
+    - ✅ `LCORE-740: type hints for models unit tests`
+    - ❌ `LCORE-0000: placeholder key`
 * Fill-in all relevant information in the PR template
     - unused parts of PR template (like information about testing etc.) can be deleted
 * Please note that CodeRabbitAI will create a summary of your pull request