sidecar

Amicus: Multi-Model Sidecar Tool

Spawn parallel conversations with different LLMs (Gemini, GPT, ChatGPT, Codex, o3, etc.) and fold results back into your context.

Slash invocation (/amicus:sidecar <model> <prompt…>)

When invoked as a slash command with arguments:

• First argument (the model): $1
• Full argument string: $ARGUMENTS

Treat $1 as the target model alias and the remainder of $ARGUMENTS as the prompt. If $1 is not a plausible model alias (gemini, gemini-pro, gpt, codex, deepseek, qwen, grok, mistral, glm, …), treat the ENTIRE argument string as the prompt and default to gemini. Then apply the critical rules below exactly as for any other invocation (run_in_background: true, --prompt-file for long briefings, interactive by default for a single model, never o3/o3-pro unprompted).

Operating Rules

These rules are mandatory for every amicus invocation in this skill:

1. ALWAYS launch amicus CLI commands with the Bash tool's run_in_background: true. Never run amicus start/resume/continue in the foreground.
2. The fold summary returns on stdout when the user clicks Fold in the GUI or the headless agent finishes. Use TaskOutput to read it when the background task completes.
3. For long or multi-line briefings, write them to a temp file and pass --prompt-file <path> (mutually exclusive with --prompt; avoids shell-quoting hazards and argument-size caps).
4. NEVER use o3 or o3-pro unless the user explicitly asks for it by name. These models are extremely expensive ($10-60+ per request). If the user asks for o3, warn them about the cost before proceeding. Default to gemini for most tasks. The CLI enforces this in code: a built-in budget gate refuses any model above a per-$/Mtok threshold (o3-pro class) before launch unless you pass --no-cost-gate; --max-cost <$> sets a soft estimated-total ceiling. When a run is refused with BUDGET_EXCEEDED, relay the gate's message — don't silently retry with the flag.
5. When the user asks to query MULTIPLE LLMs simultaneously (e.g., "ask Gemini AND ChatGPT", "compare Gemini vs GPT"), ALWAYS use --no-ui (headless) for all of them unless the user explicitly requests interactive. Opening multiple Electron windows at once is disruptive. Launch them all in parallel with run_in_background: true.
6. When the SAME prompt should go to N models, use amicus fanout --models "a,b,c" --prompt-file <path> --json (one headless wave, one JSON result) instead of N separate start calls. Different prompts per model → separate parallel amicus start --no-ui calls.
7. For a SINGLE-model sidecar, DEFAULT to interactive — omit --no-ui so the Electron UI opens and the user can watch, converse, and click Fold. Use --no-ui for a single model only when the user asks for headless/autonomous, or for unattended bulk automation. Interactive launches still use run_in_background: true.
8. If amicus is not on PATH (typical for plugin-only installs), run every command in this skill as npx -y amicus@latest <args> (e.g. npx -y amicus@latest start --model gemini --prompt "..."), or use the MCP tools (amicus_start, amicus_wait, amicus_status, amicus_read, …) instead. Do not conclude the tool is broken because amicus is not found.