Compare AI tools

	Perplexity S	Sudowrite S	Claude Agent SDK S	Devin A
Tagline	AI search done right. Cited answers, not chat theater.	AI writing tool built specifically for fiction writers.	Anthropic's SDK for building your own agents on Claude.	Cognition Labs' autonomous coding engineer.
Category	Research	Writing	Agents	Agents
Pricing	Free + $20/mo Pro	$19-$59/mo	API usage + SDK is free	$500/mo
Best for	Replacing Google for any question where you want a cited answer in seconds.	Novelists, screenwriters, fiction short-form writers.	Developers building custom agents for their own company/product.	Engineering teams offloading tickets. Ops/platform work.
Strengths	Sources every claim Fast, current answers Pro Search runs multi-step research Spaces for persistent context	Brainstorm, expand, rewrite modes designed for fiction Story Bible for character + plot tracking Understands voice + tone better than generic chatbots	Production-grade agent primitives Built on Claude (best reasoning) Full control — build exactly what you need	Works like an engineer — takes Slack tasks, opens PRs Handles multi-hour engineering work Reports back with what it did
Weaknesses	Not a general chatbot Answers can be shallow on complex topics	Pricey for casual use Fiction-only focus — not for business writing	Developer-only You build the UI	Expensive Best for well-scoped tasks Not for solo hobbyists
Kai's verdict	S-tier for search. I use it before Google now. If you're still Googling everything, try this for a week.	S-tier for fiction. If you're writing a novel, this beats raw ChatGPT every time.	S-tier for builders. The right primitives. What Kai is built on under the hood.	A-tier for the right use case. Not for solo devs. If you manage engineers, try one license.
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