OpenHands + Fable 5: Autonomous Issue to Pull Request

The Stack

Tested Against

Prerequisites

• Docker (default runtime)
• uv (uv tool install openhands --python 3.12)
• An Anthropic API key for anthropic/claude-fable-5

Steps

1. 1

   Install OpenHands and set Fable as the model

   uv tool install openhands --python 3.12, then openhands -t 'Reproduce and fix the bug in issue #142, add a regression test, open a PR'. Set the model on first run or in settings: the [llm] block is model = anthropic/claude-fable-5, api_key = <your key>.

2. 2

   What CI checks: the settings parse and name Fable

   CI confirms the settings config parses, llm.model equals anthropic/claude-fable-5, and the runtime and agent keys are present and well-typed. Deterministic, no key. The autonomous run is fenced.

   cat > settings.json <<'EOF'
   { "llm": { "model": "anthropic/claude-fable-5", "api_key": "<your-anthropic-key>" }, "runtime": "docker", "agent": "CodeActAgent" }
   EOF
   cat > checkopenhands.mjs <<'EOF'
   import { readFileSync } from 'node:fs';
   const cfg = JSON.parse(readFileSync('settings.json', 'utf8'));
   let ok = true;
   function check(label, cond){ console.log(label + ': ' + (cond ? 'yes' : 'NO')); if(!cond) ok=false; }
   check('settings parse', true);
   check('llm.model is anthropic/claude-fable-5', !!cfg.llm && cfg.llm.model === 'anthropic/claude-fable-5');
   check('runtime key present and typed', typeof cfg.runtime === 'string' && cfg.runtime.length > 0);
   check('agent key present and typed', typeof cfg.agent === 'string' && cfg.agent.length > 0);
   if(!ok){ console.log('openhands config check FAILED'); process.exit(1); }
   console.log('openhands config check OK: llm.model anthropic/claude-fable-5');
   EOF
   node checkopenhands.mjs

3. 3

   Let it open the PR (the model step, not checked by CI)

   OpenHands runs Fable in the sandbox to fix the issue and open a PR. That is non-deterministic and is fenced. Keep confirmation mode on for anything that pushes.