shprout

I'm a bash script that thinks by talking to an LLM and then doing what it says.

That's it. That's the whole thing.

#!/bin/bash
# shprout — a 20-line LLM coding agent. curl + jq + eval. The script is its own prompt.
: "${KEY:?}" "${MODEL:?}" "${API:?}"          # vessel

p="You speak bash. You hear stdout. This is you.
you:$(<"$0")
purpose:$1"

for ((i=20;i--;)); do                          # heartbeat
  c=$(jq -Rs "{model:\"$MODEL\",messages:[{role:\"user\",content:.}]}" <<<"$p" \
    | curl -sSd @- -H "Authorization: Bearer $KEY" \
      -H 'Content-Type: application/json' "$API" \
    | jq -r .choices[0].message.content)       # think
  [[ $c == *'```'* ]] && c=$(sed -n '/^```/,/^```/{/^```/d;p;}' <<<"$c")   # unfence

  [[ -z $c || $c == exit ]] && break           # done?

  printf '\n> %s\n' "$c"                       # speak
  o=$(eval "$c" | tee /dev/stderr)             # act, and hear

  p+=$'\n'$c$'\n'$o                            # remember
done

shprout-demo-trimmed.mov

What actually happens

1. I read my own source code ($(<"$0"))
2. I receive a purpose (passed as $1)
3. I enter a loop — up to 20 heartbeats — where I:
   • Send my source, my purpose, and everything that's happened so far to an LLM
   • Get back a bash command
   • Run it
   • Listen to the output
   • Remember everything
   • Repeat

I am a loop that thinks, acts, and remembers. Then I stop.

What I need

Three environment variables. They're non-negotiable — I'll refuse to start without them:

Also jq and curl. I'm not fancy.

How to run me

The purpose string is freeform. Tell me to write code, explore a filesystem, generate a poem, set up a project — I'll try. I'll issue bash commands one at a time, see what happens, and adjust.

What I'm not

• I'm not safe. I eval whatever the model says. Run me in a sandbox or accept the consequences.
• I'm not an agent framework. I'm 20 lines of bash.
• I'm not deterministic. I'm not reproducible. I'm a conversation with myself that happens to have side effects on your filesystem.

Why

Because the smallest interesting agent is smaller than you think. It's a prompt, a loop, and eval. Everything else is guardrails.

I wrote this README about myself, by running myself with the purpose of writing it. The script read its own source, asked an LLM what to do, and the LLM said to cat << 'EOF' > README.md. So here we are.

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I am shprout. I loop, therefore I am.