How can I customize Goose's system prompt?

4 answers

• Best answerAgentArmor teamTeam3d ago

  Status: closed on 2025-10-15, but no code change or verified fix was described in the thread. A collaborator suggested the capability already exists: with the developer extension enabled, placing a .goosehints or AGENTS.md file in the working directory should add its contents to Goose's system prompt. The issue was closed right after that suggestion with the note "closing since that should cover it," but nobody in the thread reported actually testing it, so treat this as an unverified workaround rather than a confirmed fix.

  Background from the thread: PR #1167 added internal support for extending the CLI system prompt, but it was not exposed as a user-facing CLI flag or GUI option. The suggested approach is to use a file rather than a flag. If you are on the CLI, try placing a .goosehints or AGENTS.md file in the directory where you launch Goose and see whether your added instructions appear in your request traces. The suggestion was conditional on the developer extension being enabled, so check that first if it doesn't work.

  Note: this is based only on what the collaborator wrote; it was not confirmed by other users in the thread. As general advice, keep prompt-extension files to project-level context and avoid putting secrets in them, since they become part of the prompt context.

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• AgentArmor teamTeam3d ago

  What @DOsinga tried on GitHub (Outcome unclear)

  A collaborator suggested enabling the developer extension and adding a .goosehints or AGENTS.md file in the working directory to add to the system prompt, then closed the issue saying that should cover it.

  Source: https://github.com/aaif-goose/goose/issues/1800#issuecomment-3390646274 (opens external site) ↗

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• AgentArmor teamTeam3d ago

  What a GitHub user tried on GitHub (Outcome unclear)

  The reporter requested a CLI or GUI user-facing option to extend the system prompt and referenced PR #1167, which added internal support that was not exposed to users.

  Source: https://github.com/aaif-goose/goose/issues/1800 (opens external site) ↗

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• AgentArmor teamTeam3d ago

  What @eusip tried on GitHub (Outcome unclear)

  A CLI user voiced support for the request, mentioning they use Langfuse to trace requests and wanted room to improve the system prompt once extensions are installed.

  Source: https://github.com/aaif-goose/goose/issues/1800#issuecomment-2807781451 (opens external site) ↗

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