Marketplace (Skills, Agents, Plugins)

The Marketplace (grid icon) is the in-app store for extending the agent: skills, autonomous agents, MCP bridges, context compactors, and UI plugins — all open source.

Categories

The catalog is large — roughly 190 entries across five categories. The table below shows the count and a representative sample of each; use the filter buttons at the top of the Marketplace to browse a category in full.

Category	Count	Examples
Skills	58	TDD Specialist, Refactoring, API Design, SQL Optimization, Regex Wizard, Accessibility Audit, Git Workflow, Docs Writer, Domain-Driven Design, CQRS & Event Sourcing, GraphQL Schema, gRPC & Protobuf, OAuth & OIDC, Cryptography Review, Threat Modelling, OWASP Top 10, Load Testing, Chaos Engineering, Contract Testing, Property-Based Testing, Mutation Testing, Snapshot Testing, End-to-End Browser Testing, Accessibility Testing, Observability Design, SLO & Error Budget, Incident Response, Runbook Authoring, Cloud Cost Optimisation, Data Modelling, ETL & Data Pipeline, Event Streaming, Caching Strategy, Concurrency & Locking, Memory Profiling, API Versioning, Feature Flag, Monorepo Tooling, Docs-as-Code, Architecture Decision Records, Code Review, Legacy Code Rescue, Dependency Audit
Autonomous Agents	49	Axion Agent (default — installed), Claude (Anthropic), Antigravity (Google), Codex (OpenAI), Gemini (Google), DeepSeek Coder, Qwen Coder, OpenHands, Aider, SWE-Agent, Code Review, Legacy Migration, Performance Optimisation, Security Remediation, Documentation, API Reference, Test Gap, Flaky Test Hunter, Dead Code Removal, Dependency Upgrade, CVE Triage, Localisation, Accessibility Remediation, Database Schema, Query Optimisation, Infrastructure, Kubernetes, CI Pipeline, Release, Changelog, Pull Request Review, Issue Triage, Bug Reproduction, Codebase Onboarding, Architecture Review, Cloud Cost, Log Analysis, Postmortem, Compliance, SBOM, Refactoring, Docstring
Compactors	34	Repomix, Code2Prompt, Universal Ctags, Gitingest, Tree-sitter AST, Signature-Only, Diff-Only, Import Graph, Call Graph, Semantic Chunk, Embedding Rank, BM25 Keyword, Hybrid Retrieval, Cross-Encoder Rerank, Recursive Summariser, Hierarchical Summary, Rolling Window, Near-Duplicate, Whitespace Minifier, Comment Stripper, Test-Aware, Config, Schema, OpenAPI, Log, Stack Trace, Dependency List, Git History, Blame, Docs, Notebook, Binary Asset, Token Budget, Prompt Cache
MCP Servers	3	Blender, Chrome DevTools, GitHub bridges — see MCP Servers for the full catalog of 400+
Plugins	47	Media Converter (ffmpeg), Cryptography Toolkit, Image Compressor, JSON Schema Generator, .env Manager, Cron Scheduler, Markdown Exporter, Cron Expression Builder, JSONPath Explorer, YAML Tools, XML Tools, CSV Tools, Hash & Checksum, JWT Inspector, Timestamp Converter, Three-Way Merge, Regex Explainer, Text Statistics, Case Converter, Line Tools, Escape & Unescape, Placeholder Text, QR Code, SVG Optimiser, Icon Set Generator, Screenshot Annotator, Screen Recorder, Clipboard History, Scratch Notes, TODO Scanner, License Header, Environment Diff, Port Forwarding, Database Browser, API Mock Server, Load Simulation, Dependency Graph

Installing

Click Install on any card. Installed items show a green badge.

Using skills & agents

Installed skills and autonomous agents can be toggled into the agent's system prompt from two places:

The Skills & Agents sparkle icon in the composer toolbar (checkbox per item), or
The Marketplace card toggle.

Enabled items are injected as directives on every prompt — e.g. the TDD skill instructs the agent to write tests before code, and the Axion Agent contributes its full capability playbook.

The Axion Agent

Axion Agent is the first-party default agent — it ships installed and enabled, and can be uninstalled or disabled at any time like any other item. See Axion Agent for everything it can do.

Primary compactor

For compactor entries, Set as Primary switches the workspace compactor used to build prompt context (Repomix, Code2Prompt, Ctags, Gitingest, LSP Native). The active one is shown in the composer's chip.

External Marketplace (Open VSX)

Below the built-in catalog is the External Marketplace panel. It searches a real external marketplace - Open VSX by default - and installs what it provides automatically.

Only what Axion can actually run. Axion has no VS Code extension host. Rather than install something that would silently do nothing, every extension is inspected before it is offered. Anything needing webviews, custom editors, notebook renderers, debug adapters, custom side-bar views, walkthroughs, or the web extension host is marked Not supported with a plain-English reason, and its install button is disabled.

What gets installed, and how

Kind	What Axion does with it
Language Server	Unpacks it and launches its server over LSP.
MCP Server	Registers it as a tool bridge in the MCP Hub.
Theme	Converts its VS Code colours into Axion's 13 theme slots and applies it live.
Snippets	Imports its snippet files.
Agent Skill	Registers its instructions as a prompt directive.

Using it

Open the Marketplace view.
Type a search (e.g. python, java, theme, mcp) and press Search.
Each result shows its kind, a Compatible / Not supported badge, and the reason it was classified that way.
Click Install - Axion downloads the .vsix, unpacks it, and wires it up.

The Compatible only checkbox (on by default) hides unsupported extensions. Turn it off to see them greyed out with the reason, so nothing is hidden from you.

Installs survive a restart. Installed extensions are saved to the encrypted vault and re-registered on the next launch, so your themes, language servers, and skills are still there.

Extensions are unpacked into %LocalAppData%\AxionIDE\extensions\<publisher>.<name>. When an extension only publishes a build for another operating system or CPU, Axion reports "No compatible build for this platform" instead of installing something that cannot run.