Compare AI tools

	Symphony A	Grammarly A	GitHub Copilot B	Kling A
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.	Grammar check + tone + AI drafting, everywhere you type.	Microsoft/GitHub's autocomplete. Deep VS Code + JetBrains integration.	Kuaishou's video model. The surprise standout.
Category	Agents	Writing	Coding	Video
Pricing	Free (open-source)	Free + $12-$15/mo Premium + team plans	Free (limited) + $10/mo Pro + $19/mo Business	Credit-based, free trial
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.	Non-native English writers, business email, anyone who types a lot.	Teams with GitHub already. Devs who don't want to change IDEs.	Anyone who wants top-tier video quality for less.
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	Works in every browser/app Now has generative AI (GrammarlyGO) Tone detection + suggestions	Great enterprise story Works in your existing IDE Chat + autocomplete	Very strong motion + physics Often beats Runway on realism Great price
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	Can feel naggy Premium features gate basics Privacy concerns (reads your writing)	Less agentic than Cursor/Claude Code Model quality varies	UX is rough for English speakers Queue times
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.)	A-tier for non-native English speakers. B-tier if your English is already strong — Claude does better with tone.	B-tier. Solid for autocomplete but the category moved past it. Pick Cursor unless you can't.	A-tier. Rising fast. If you can tolerate the UX, quality per dollar is best-in-class.
Link	Open →	Open →	Open →	Open →