Companies

Tessl

tessl.io

Tessl provides governed context, skills, evaluations, and software-factory infrastructure for AI coding agents.

HQLondon, Not applicable, United Kingdom
Employees11-50
Funding$125M
Valuation$0.5B
8 active roles
Profile 6mo agoJobs checked 3h ago
AI / MLAI ApplicationB2B SaaSSeries A$50M-$200M

About

Tessl builds an agent-enablement platform for development teams and organizations adopting AI coding agents. Its differentiated offering combines structured, versioned context with a searchable skills registry, evaluations, integrations, and enterprise-grade security and governance for continuously improving AI-native software development.

Market

Tessl competes in the AI-native software-development and AI coding-agent infrastructure market, positioning itself as an enablement and context layer rather than only an end-user coding assistant. Its differentiation is the lifecycle management of versioned, evaluated agent skills and structured context, combined with spec-driven workflows, enterprise governance, open standards, and MCP-based interoperability. The competitive set includes broad AI coding assistants such as GitHub Copilot, Cursor, and Tabnine, as well as repo-scale or spec-driven tools such as Sourcegraph Cody, Augment Code, and Kiro.

Target Customers

Tessl targets software development teams—especially mid-market and enterprise engineering organizations working on complex, real-world codebases and adopting multiple AI coding agents. Likely buyers are engineering, developer-platform, and software-architecture leaders responsible for developer productivity, reliability, security, and governance.

At a Glance

Problem

AI coding agents can produce code quickly but remain unreliable and overconfident: they may act before understanding the task, choose the wrong implementation, leave work unfinished, or repeat mistakes. As AI-generated code expands, maintaining dependencies and ensuring that components fit together compounds the risk of security incidents, downtime, cost, and wasted engineering effort. Within enterprises, agent adoption also creates a management problem: skill libraries accumulate duplicate, stale, and untested instructions, while teams cannot tell whether a skill actually improves output.

The main use case is helping engineering organizations scale coding agents beyond isolated experiments into reliable production development. Tessl targets the point where agents must work repeatedly across real codebases, follow organizational standards, use libraries correctly, and produce code that can be maintained as the software evolves.

Product / Service

Tessl is an agent-enablement platform that gives coding agents structured, versioned context and a governance layer. Its platform includes an agent-agnostic registry and package manager for discovering, installing, versioning, and rolling back skills and plugins, along with evaluation and observability capabilities that measure whether context is actually improving agent performance. It integrates with agents such as Claude Code, Cursor, Copilot, and Gemini, allowing teams to manage shared context without being locked into one coding assistant.

Its spec-driven development products capture intent in structured specifications that live with the codebase, connect capabilities to tests, and provide guardrails for implementation and future changes. The Spec Registry supplies more than 10,000 pre-built specifications for open-source libraries, helping agents avoid API hallucinations and version mix-ups; teams can also publish internal specifications covering their own technology stacks, APIs, and security policies. The Registry launched in open beta, while the Tessl Framework initially entered closed beta, with the benefit of making AI-generated software more reliable, maintainable, and easier to govern.

Market

Tessl operates in AI-native software development, developer infrastructure, and the emerging market for agent-enablement and context-management platforms. It overlaps with AI coding products such as Cursor, Poolside, and GitHub’s offerings, although Tessl is positioned less as a standalone coding assistant than as the system of record and governance layer that can work across coding agents. Other identified alternatives include Ona, DiffBlue, and CodeGPT; spec-driven development tools such as Kiro, BMAD, and OpenSpec are adjacent substitutes for parts of its workflow.

The company has substantial investor traction but limited publicly evidenced commercial traction in the available research. It announced $125 million in funding—$25 million led by boldstart and GV and a $100 million Series A led by Index with Accel participating—and TechCrunch reported a $750 million post-money valuation. In November 2024 it had no shipped product or customers; by September 2025 it had launched the Spec Registry in open beta and the Framework in closed beta, with more than 10,000 pre-built specs. The evidence does not provide current revenue or customer counts, so Tessl should be characterized as a well-funded, beta-stage company with product traction rather than a company with quantified commercial traction or proven revenue scale.

Founders & Leadership

Guy PodjarnyFounder
Founder & CEO
Dru KnoxHead of Product
Maurilio ComettoHead of Engineering
Stephanie DominyGeneral Counsel and Head of Operations
Simon MapleHead of DevRel

Funding History

2024-04
Seed$25M

boldstart Ventures, GV

2024-11
Series A$100M

Index Ventures

Recent News

2026-06-23product
The new Tessl review: now you decide what "good" looks like

Tessl introduced a review capability that lets users define their own criteria for skill quality, apply agent-based accuracy checks, and retain a history of review runs.

2026-06-03
Tessl Review (2026): The Spec-as-Source Bet

CodeMySpec published a review covering Tessl’s Framework, skill registry, pricing, $125 million in reported funding, and which capabilities were shipping versus still in beta.

2026-03-19partnership
Getting started with Tessl & GitHub Copilot

Tessl announced that its integration with GitHub Copilot IDE and CLI is now automatic, building on its existing MCP integration and supporting setup through Tessl initialization commands.

2026-02-23product
Your AGENTS.md file isn't the problem. Your lack of AI ...

Tessl discussed its review functionality for evaluating AI-agent skills, including custom quality criteria, agent-based accuracy checks, and review-history tracking.

2026-01-29product
Announcing skills on Tessl: the package manager for agent skills

Tessl announced a package manager for agent skills, allowing developers to install skills and browse a registry containing more than 2,000 evaluated skills.

2026-01-19product
Making Claude good at Go using Context Engineering with Tessl

Tessl announced that the top 50 Go libraries were available in its registry, giving developers free access to version-specific context for those libraries.

2025-10-02
Taming AI coding agents with specifications

Tessl published an article arguing that structured specifications can help address the reliability and judgment limitations of fast-moving AI coding agents.

2025-09-23product
Tessl launches spec-driven framework and registry to make AI coding agents reliable

Tessl detailed the launch of its Spec Registry, available in open beta, and Tessl Framework, available in closed beta. The products use structured specifications and more than 10,000 usage specs to give coding agents clearer guidance and guardrails.

2025-09-16product
Announcing Tessl's Products to Unlock the Power of Agents

Tessl launched its first two products: the Tessl Framework and Tessl Spec Registry. The Registry entered open beta, while the Framework entered closed beta, introducing Tessl’s spec-driven development approach.

2025-09-08
Agents.md: an open standard for AI coding agents

Tessl highlighted AGENTS.md as a shared file standard for AI assistants, intended to make project instructions reusable and consistent across development workflows.

Active Roles

8
London Office/Engineering/1d ago
New York/Forward-Deployed Engineer/66d ago
London Office/Product/71d ago
London Office/Engineering/197d ago

Business Model

Tessl monetizes through free and paid subscription plans: Free at $0 per month, Team at $100 per month, and custom Enterprise plans. Paid customers purchase credits for reviews, evaluations, and agent runs, with credit top-ups, usage-based overages, and enterprise platform fees.

Products

Tessl AI-native software development and agent-context platformAgent skills package manager and registrySpec-driven development framework and registryTessl MCP server and coding-agent integrations

Tech Stack

AI coding agentsModel Context Protocol (MCP)Structured, versioned agent contextSpec-driven developmentOpen standards and repository-native plain-text artifacts

Competitors

GitHub Copilot
Cursor
Tabnine
Sourcegraph Cody
Augment Code
Kiro

Key Investors

Index Ventures, Google Ventures, Accel, Boldstart Ventures