Prompt Files (prompts)

Gaunt Sloth composes its system prompt from seven segments, each backed by a prompt file. The prompts config object retargets, disables, or composes any segment — most commonly to feed the agent your project’s coding guidelines.

Lead use case: give the agent your project guidelines

Goal: your coding rules already live in an AGENTS.md at the repo root, and you want every gth run to load them as guidelines instead of maintaining a second copy in .gsloth.guidelines.md.

Point the guidelines segment at that file in .gsloth.config.json:

{
  "prompts": {
    "guidelines": "AGENTS.md"
  }
}

The string "AGENTS.md" is shorthand for { "path": "AGENTS.md" }: the file replaces the built-in guidelines segment, so AGENTS.md is now read into the system prompt on every command. No flag, no per-run pasting. To keep both your .gsloth.guidelines.md and an appended AGENTS.md, use the object form with "mode": "append" (below).

For the coding-workflow walkthrough of this — including the default-file path that needs no config at all — see the Code with your own project rules guide. This page is the full segment reference it points to.

The seven segments

Each segment is backed by a prompt file with a well-known default name:

Segment	Default file	Used
backstory	.gsloth.backstory.md	every command (identity)
guidelines	.gsloth.guidelines.md	every command (project guidelines)
system	.gsloth.system.md	every command (appended last)
chat	.gsloth.chat.md	chat mode prompt
code	.gsloth.code.md	code mode prompt
exec	.gsloth.exec.md	exec mode prompt
review	.gsloth.review.md	review / pr instructions

With no config, each segment reads its default-named file from the config dir (.gsloth/.gsloth-settings/, honouring identity profiles) or the project root, falling back to the bundled default shipped with the installation.

gth init scaffolds only .gsloth.config.json — no template prompt files are planted; the bundled defaults apply until you add your own files or prompts config.

The prompts object

The prompts config object retargets, disables, or extends any segment. Each segment accepts a string (a file path — the common case) or an object { path?, enabled?, mode? }:

{
  "prompts": {
    "guidelines": "AGENTS.md",
    "review": { "path": "docs/review-checklist.md", "mode": "append" },
    "backstory": { "enabled": false }
  }
}

• A string is shorthand for { "path": … }: the file replaces the segment’s built-in content. Pointing guidelines at an existing AGENTS.md is the typical use.
• path resolves like every prompt file: the config dir (and identity profile) first, then relative to the project root.
• enabled: false drops the segment entirely — even its bundled default. Use it to run without a segment rather than shadowing it with an empty file.
• mode controls composition when path is set: "replace" (default) substitutes the built-in segment content; "append" keeps the built-in content (your default-named file, or the bundled default) and appends the file after it — use it to add project rules on top of the stock review prompt instead of rewriting it.

Turning off the bundled defaults (noDefaultPrompts)

By default, Gaunt Sloth falls back to its bundled .gsloth.*.md prompt files when no user-provided files are found. Setting noDefaultPrompts to true disables this fallback, so only user-provided prompt files are used. This applies to all .gsloth.*.md files including backstory, system, chat, code, guidelines, and review instructions.

{
  "noDefaultPrompts": true
}

To drop a single segment (including its bundled default), use prompts.<segment>.enabled: false instead — noDefaultPrompts is the all-segments switch.