use code engine nuclei-templates, and use -sign return:[INF] All templates signatures were elaborated success=1 failed=0, but still Could not run nuclei: no templates provided for scan

[237693991]

./nuclei -t  ./44_test.yaml -sign
[INF] All templates signatures were elaborated success=1 failed=0

 ./nuclei -u http://example.com -t ./44_test.yaml  -code
                     __     _
   ____  __  _______/ /__  (_)
  / __ \/ / / / ___/ / _ \/ /
 / / / / /_/ / /__/ /  __/ /
/_/ /_/\__,_/\___/_/\___/_/   v3.4.10

                projectdiscovery.io

[INF] Current nuclei version: v3.4.10 (latest)
[INF] Current nuclei-templates version: v10.2.8 (latest)
[INF] Targets loaded for current scan: 1
[INF] Scan completed in 2.959145ms. No results found.
[FTL] Could not run nuclei: no templates provided for scan

id: hello-python-output
info:
  name: Hello Python Output Test
  author: your_name
  severity: info
  description: "Execute Python code and match output"

code:
  - engine:
      - py
      - python3
    source: |
      import sys
      print("Hello from Nuclei Python code template!")
      print("Status: OK")

matches:
  - type: word
    words:
      - "Status: OK"
    part: body

[Mehrdoost]

Hi there!

The reason you're getting the [FTL] Could not run nuclei: no templates provided for scan error is that Nuclei is failing to validate the YAML schema of your template. When a template has syntax errors, Nuclei silently drops it during the loading phase, resulting in zero templates being passed to the engine.

There are two minor syntax issues in your template:

You used the keyword matches: instead of matchers:.

The matchers block must be correctly indented so it belongs to the specific code execution block, rather than sitting at the root level of the template.

Here is the corrected and fully working YAML for your 44_test.yaml file:

YAML

id: hello-python-output
info:
  name: Hello Python Output Test
  author: your_name
  severity: info
  description: "Execute Python code and match output"

code:

- engine:
    - py
    - python3
  source: |
    import sys
    print("Hello from Nuclei Python code template!")
    print("Status: OK")

  matchers:
    - type: word
      words:
        - "Status: OK"

How to run it now:
Since you modified the content of the file, make sure to sign it again first to update the hash:

Bash
./nuclei -t ./44_test.yaml -sign

Then run it with your target and the -code flag:

Bash
./nuclei -u http://example.com -t ./44_test.yaml -code

Hope this solves your issue! If it works for you, please consider marking this response as the Answer so other researchers facing the same issue can find it easily.