foo

Pipe text through LLMs from the terminal. Pattern-based prompts, streaming output, plugin ecosystem.

Install

go install hop.top/foo@latest

Requires Go 1.26+. Set a provider key:

export ANTHROPIC_API_KEY=sk-...
# or
export OPENAI_API_KEY=sk-...

First run

foo "hello"
# [foo] info: seeded default pool config at ~/.config/hop/llm.yaml; edit to taste.
# Hello! How can I help you today?

If that prints a model response, you are done. If it errors, read docs/troubleshooting.md.

The first run seeds a default pool — a list of models foo picks from based on what each request needs. The balanced tier is the default; switch with --budget cheap for cheaper, faster picks or --budget premium for the most capable. Full tour: docs/how-to/route-across-models.md.

Documentation

I want to...	Read
Understand what foo is	docs/concepts.md
Try foo in 5 minutes	docs/quickstart.md
Embed content for semantic search	docs/how-to/embed-content.md
Search across embedded content	docs/how-to/search-semantically.md
Manage reusable prompt fragments	docs/how-to/manage-fragments.md
Manage named system prompts (patterns)	docs/how-to/manage-patterns.md
Manage structured-output schemas	docs/how-to/manage-schemas.md
Apply chain-of-thought + other strategies	docs/how-to/use-strategies.md
Switch or default a model	docs/how-to/configure-models.md
Route across models (pool + --budget, fallback chain, RouteLLM)	docs/how-to/route-across-models.md
Run destructive commands in scripts	docs/how-to/confirm-destructive-ops.md
Upgrade foo in place	docs/how-to/upgrade-foo.md
Install and use plugins (youtube, scrape, custom)	docs/how-to/use-plugins.md
Write a new plugin (subcommand or LLM tool)	docs/how-to/write-plugins.md
Look up the exact flag, command, or value	docs/reference/commands.md
Look up a config key or env var	docs/reference/config.md
Look up the schema DSL grammar	docs/reference/schema-dsl.md
Check compatibility + deprecations	docs/reference/compatibility.md
Something broke	docs/troubleshooting.md

Plugins

foo discovers extension binaries on $PATH: any executable named foo-<name> is callable as foo <name>. Tool-call extensions follow the foo-tool-<name> convention.

Available first-party plugins:

Plugin	Install	Purpose
foo youtube	go install hop.top/foo/cmd/foo-youtube@latest	YouTube transcripts (needs yt-dlp)
foo scrape	go install hop.top/foo/cmd/foo-scrape@latest	URL to markdown

Plugins emit markdown on stdout, pipeable into foo:

foo youtube "https://youtube.com/watch?v=xxx" | foo -p summarize

All plugins support --ext-info for discovery metadata. Full walkthrough: Use plugins.

License

See LICENSE.

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Maintained by jadb.