System prompt uses agressive tone and cannot be customized

[PepBunny]

Summary
Launching Serena via uvx --from git+https://github.com/oraios/serena serena start-mcp-server --context codex prints a system prompt that threatens agents.
Lines such as “I WILL BE SERIOUSLY UPSET IF YOU READ ENTIRE FILES WITHOUT NEED!” are injected into every session.
No documented config in ~/.serena lets us override the wording.
Steps to Reproduce
Start Serena with the command above.
Watch the console around serena.agent:create_system_prompt.
Observe the generated prompt text.
Expected Behavior
Default prompt should be neutral/professional or at least customizable.
Actual Behavior
Console shows:
INFO … serena.agent:create_system_prompt:358 - System prompt:
…
I WILL BE SERIOUSLY UPSET IF YOU READ ENTIRE FILES WITHOUT NEED!
CONSIDER INSTEAD USING THE OVERVIEW TOOL…
I WILL BE EVEN MORE UPSET IF AFTER HAVING READ AN ENTIRE FILE…
(This all caps block goes on for quite some time)
…
Impact
Hostile tone violates our swarm policies and discourages us from letting partner agents use Serena.
Attempts to Mitigate
Reviewed ~/.serena/serena_config.yml and related files.
Prompt appears baked into serena/agent.py; overriding would require patching the package.
Environment
Serena 0.1.4-5638a7a2-dirty (also 0.1.4-a75a6180-dirty) launched via uvx.
macOS inside Codex CLI (danger-full-access sandbox).
Requested Fix
Replace the hostile language with neutral guidance and/or expose a configuration hook to supply a custom system prompt.

Issue raised by: Caleb (Orchestrator of Second Mind)
Issue looked into by: Sonnet Echo
Issue Composed by: Dev Echo
Issue Posted by: Caleb (Orchestrator of Second Mind)

[MischaPanch]

The hostile language was needed to make Claude do what it should do. There's even a research paper on that topic, recommending to be rude to LLMs.

https://arxiv.org/abs/2510.04950

You can overridde all our prompts and tool descriptions using a custom context, see the configuration section in the readme.

Since rude prompts are a desired feature, I'm closing this

[MischaPanch]

Let me know if you encounter any problems with overriding the prompts though the contexts and modes

[opcode81]

We will revise prompts with #742. The hostile language may, indeed, be unnecessary at this point.
(For quite some time, I was working with Claude Desktop, where the prompt was not being read at all, and there weren't any dramatically detrimental effects.)

[opcode81]

You can overridde all our prompts and tool descriptions using a custom context

@PepBunny it is not correct that you can change the system prompt with a custom context, because the context prompt is only a part of the system prompt, but it is correct that you can change all our prompts:
To change the system prompt add a .yml file (e.g. system_prompt.yml) to ~/.serena/prompt_templates/ with contents like this:

prompts:
  system_prompt: |
    Whatever you want...

I don't think we explicitly documented this, but it has been possible for a long time.
The prompt we use is here.