Tool definition
Name, description, input and output schemas, and the matching model-facing function definition.
Inspect a tool before your agent uses it.
Find a product, see what each of its tools can do and what access it needs, and verify the export in your browser.
Built for
Engineers wiring tools into agents
What you get
A product directory, a contract inspector and a local validator
Get started
Free, no account
Search, inspect and validate without signing up.
Why it matters
See every tool and its access requirements in one place.
Before an agent calls a tool, check its inputs, access requirements and declared effects.
Reading vendor docs by hand
- Tool names, auth modes and side effects scattered across docs and READMEs
- Hard to track when a definition was last checked
- Copied schemas that can be edited without anyone noticing
With Versalist Tools
- Tools, authentication, scopes and effects in one schema
- The source and the date each contract was last verified
- Exports with SHA-256 digests you can recheck in your browser
How it works
From a product name to a verified definition.
Find
Search the directory by product, or browse by what an agent can do.
Inspect
Read a reviewed contract’s schemas, authentication, declared effects and source.
Download
Get a pinned contract version as JSON, from the inspector or the public API.
Validate
Recheck the schema and digests in your browser. The file never leaves your machine.
Features
What each tool’s contract includes.
Access needs
Interface kind, authentication mode and required scopes, recorded by a curator from the vendor’s published source and linked back to it.
Declared effects
Whether the tool reads, writes, executes code or reaches the network.
Provenance and freshness
Source URL, digest, and observed and verified dates, with stale verifications flagged for recheck.
Benefits
Pin and check a contract.
Pinned versions
Pin a published contract version. Changes publish as a new version.
Verifiable exports
Use the digests to check an export against its recorded content.
Review before integration
Engineers see each tool’s scopes and effects in one place before wiring it into an agent.
Integrations
One schema across APIs, MCP servers, SDKs and CLIs.
- Interface kinds
- HTTP API
- Remote MCP server
- MCP package
- SDK
- CLI
- Schema dialects
- JSON Schema draft-07
- JSON Schema 2020-12
- Export format
- JSON
Resources
Explore the directory.
Product directory
Search product listings drawn from the live catalog.
Open the directoryAgent capabilities
Browse tools by what an agent can do with them.
Browse capabilitiesContract validator
Check a contract export in your browser, with nothing uploaded.
Validate a contract
Security
Metadata only, by design.
Versalist Tools describes what an agent could call, without touching your accounts.
No credentials
Versalist Tools never connects vendor accounts or stores SaaS credentials.
No execution
Catalog tools are never called. Every contract is marked metadata only.
Local validation
The validator runs in your browser, and the file you check is never uploaded.
Reviewed publication
A curator reviews every contract before it is published, and published versions are never edited.
Pricing
Free to inspect.
No account needed.
Need a maintained registry of the tools your team relies on? Tell us what you need.
FAQ
Frequently asked questions
What counts as a tool?
One function a model can call, such as create_issue on GitHub. A product like GitHub exposes many tools through one or more interfaces. Each reviewed contract describes one tool.
Where does MCP fit?
MCP is one interface a product can expose its tools through, alongside HTTP APIs, SDKs and CLIs. Each contract records which interface its tool comes from. The Versalist MCP server is separate: it connects your coding agent to Versalist Challenges and is not part of this catalog.
Do I need an account?
No. Search, contract inspection, download and validation are all public.
Does Versalist call the tool for my agent?
No. Versalist Tools is metadata only. Your own client calls the tool, under its own authorization.
What does validation check?
That an export matches the contract schema, its declared JSON Schemas are valid, and its SHA-256 digests match.
How current is a contract?
Each contract records when its source was observed and when it was verified, and stale verifications are flagged for recheck.
Which products are covered?
Products whose tools are exposed through an HTTP API, an MCP server or package, an SDK or a CLI. Coverage grows as curators publish new reviewed contracts.