StartupLondon, UK
Tessl
Agent enablement platform and registry for building, evaluating and distributing agent skills.
Tessl, founded by Guy Podjarny, describes itself as the management layer between developers and their coding agents (Claude Code, Cursor, GitHub Copilot, Gemini and others). The Tessl Platform acts as a control plane for agent context, tackling duplicate skills, tracking skill quality and usage with before-and-after evals, and scanning skills for security. The Tessl Registry indexes skills across an organisation, and Loops run skills on a schedule for tasks like code review and docs maintenance. In September 2025 it launched the Tessl Framework and Spec Registry for spec-driven development.
Neighbours in the directory
San Francisco, CA · Est. 2022
The de-facto standard toolkit for building LLM applications and agents.
LangChain makes the LangChain framework and LangGraph, the low-level orchestration standard for stateful, controllable agents, plus the LangSmith platform for tracing, evaluating and monitoring them in production.
~$75M raised
San Francisco, CA · Est. 2023
Devin, the AI software engineer, and the Windsurf IDE.
Cognition builds Devin, an autonomous AI software engineer that plans and executes engineering tasks end-to-end, and acquired the Windsurf agentic IDE in 2025. One of the defining startups of the coding-agent wave.
~$10.2B valuation (Sep 2025)
San Francisco, CA · Est. 2023
The integration layer: hundreds of managed tools your agents can call.
Composio handles auth, schemas, observability and reliability for the external SaaS tools an agent uses — 'plumbing for agentic actions' across Slack, GitHub, Salesforce and 250+ other surfaces.
Connections
Relations from the Harness Hub knowledge graph, as charted in the State of Harness reports.
Built on · 1
- Claude CodeProject
Sources
Verified Oct 29, 2026