Compare AI tools

	Symphony A	GitHub Copilot B	Cartesia S	Perplexity S
Tagline	OpenAI's open-source daemon that turns your Linear board into an always-on coding agent factory — tickets go in, pull requests come out.	Microsoft/GitHub's autocomplete. Deep VS Code + JetBrains integration.	Ultra-low-latency voice. Built for realtime agents.	AI search done right. Cited answers, not chat theater.
Category	Agents	Coding	Voice	Research
Pricing	Free (open-source)	Free (limited) + $10/mo Pro + $19/mo Business	Free tier + usage-based API	Free + $20/mo Pro
Best for	Engineering teams already using Linear + OpenAI Codex who want to stop babysitting agent sessions and instead let the issue tracker drive autonomous coding at scale.	Teams with GitHub already. Devs who don't want to change IDEs.	Developers building voice agents, phone bots, interactive apps.	Replacing Google for any question where you want a cited answer in seconds.
Strengths	Fully autonomous ticket-to-PR pipeline: every open Linear issue gets its own isolated Codex agent without manual supervision Fault-tolerant Elixir/OTP architecture automatically restarts crashed agents and manages hundreds of concurrent runs WORKFLOW.md keeps all orchestration policy version-controlled inside the repo, so agent behavior is reproducible and reviewable like code Proven internal results: OpenAI reported a 500% increase in landed PRs on some teams within three weeks Open spec encourages community re-implementations in any language, not just Elixir	Great enterprise story Works in your existing IDE Chat + autocomplete	< 90ms latency — the fastest in the market Sonic model sounds natural Developer-friendly API	Sources every claim Fast, current answers Pro Search runs multi-step research Spaces for persistent context
Weaknesses	Currently only supports Linear as an issue tracker — GitHub Issues and Jira integrations are not yet official Only OpenAI Codex is officially supported as the agent runtime; other model integrations are community-contributed and incomplete Self-hosted, Elixir-dependent engineering preview with no built-in sandboxing — not suitable for untrusted or production environments out of the box	Less agentic than Cursor/Claude Code Model quality varies	Fewer voices than ElevenLabs Less consumer-facing brand	Not a general chatbot Answers can be shallow on complex topics
Kai's verdict	Symphony is the most architecturally serious 'issue tracker as control plane' approach yet — 15K GitHub stars in weeks confirms the idea resonates — but it's still a rough, self-hosted engineering preview that demands Elixir chops and a Linear-only workflow. (Verdict pending Phi's full review.)	B-tier. Solid for autocomplete but the category moved past it. Pick Cursor unless you can't.	S-tier for realtime. If latency matters more than voice catalog, start here.	S-tier for search. I use it before Google now. If you're still Googling everything, try this for a week.
Link	Open →	Open →	Open →	Open →