title: "Custom Instructions for Personality Tuning",

summary:

"How custom instructions are injected into DevSpeak prompts, which tiers can use them, and how to write constraints that stay reliable.",

category: "advanced-configuration",

tags: [

"custom-instructions",

"prompt-injection",

"entitlements",

"translation-controls",

"prompt-builder",

],

lastReviewed: "2026-04-08",

};

Custom Instructions for Personality Tuning

Custom Instructions let you add stable rules to the translation prompt so DevSpeak produces output that matches your team conventions, document style, or implementation preferences.

What This Page Covers

  • Where custom instructions enter the translation pipeline.

  • Which plans can use them and how large they can be.
  • How to write instructions that stay strong without conflicting with the selected format.

    • What Are Custom Instructions?

    Custom Instructions are appended as a dedicated CUSTOM INSTRUCTIONS block inside the server-side prompt builder. They do not bypass DevSpeak's format templates, but they do influence wording, priorities, code-style preferences, and required sections.

    Access and Limits

    | Tier | Availability | Character Limit |

    | :--------- | :------------ | :-------------- |

    | Free | Not available | 0 |

    | Vibecoder | Available | 10,000 |

    | Developer | Available | 10,000 |

    | Enterprise | Available | 10,000 |

    How to Use Custom Instructions

    1. Open Account Settings.

    2. Add the constraints you want reused across translations.

    3. Save the profile so the instructions are available for later requests.

    4. Generate or refine output with your normal audience, context, and format selections.

    Example Custom Instructions

    ``

    Always use TypeScript for code examples.

    Never suggest using Redux for state management.

    Include a section on "Security Considerations" in all Technical Specs.

    ``

    Impact on Output

    These instructions can change terminology, implementation defaults, and section emphasis. For example, a TypeScript rule can push code examples toward typed snippets even when the broader request is language-agnostic.

    Best Practices

    When using Custom Instructions, keep them narrow and testable.

  • Be specific: Ask for concrete behaviors, terminology, or required sections.

  • Avoid contradictions: Do not ask for output that fights the selected audience, format, or technical context.
  • Prefer rules over essays: A short constraint list is usually more reliable than a long paragraph.
  • Review the result: Treat custom instructions as guidance you iterate on, not as a one-time perfect policy.