Chemical Sourcing (ToolUniverse Claude Skill)

A ToolUniverse agent skill that answers “where can I buy this compound, and at what purity and price?” — and, when the exact compound is unavailable, what to buy instead.

   
Type Claude Skill (one of ToolUniverse’s pre-built agent skills)
Supplier Zitnik Lab, Harvard Medical School
Availability GA — part of the ToolUniverse skills collection (skills/tooluniverse-chemical-sourcing/)
Pricing Free / OSS (Apache-2.0); wraps public and vendor catalogs (PubChem, ChEMBL, ZINC, Enamine, eMolecules, Mcule)
Capabilities Read-only — searches catalogs and compares listings; places no orders
Verified works · 2026-08-06
Security cleared · 2026-08-06 — ToolUniverse Apache-2.0, public read-only catalogs, no credentials

How to install

This skill calls ToolUniverse tools, so the ToolUniverse MCP server must be installed first (see the ToolUniverse page). Simplest registration:

claude mcp add --transport stdio tooluniverse -- uvx tooluniverse

Then add the skills:

  • Claude Code — install the whole skill collection (the skill resolves as tooluniverse-chemical-sourcing): 
    npx skills add mims-harvard/ToolUniverse
  • Manual / other agents — copy just this skill directory into your skills folder: 
    git clone https://github.com/mims-harvard/ToolUniverse
cp -r ToolUniverse/skills/tooluniverse-chemical-sourcing ~/.claude/skills/

    (replace ~/.claude/skills/ with your agent’s skills directory if you are not using Claude Code/Desktop.)

The skill sets disable-model-invocation: true upstream, so invoke it explicitly (e.g. ask Claude to “use the chemical-sourcing skill”) rather than relying on automatic dispatch.

What it does

Runs a five-phase procurement workflow over ten ToolUniverse tools — PubChem_get_CID_by_compound_name, PubChem_get_compound_properties_by_CID, ChEMBL_get_molecule, ZINC_search_compounds, ZINC_get_compound, Enamine_search_catalog, Enamine_get_compound, eMolecules_search, eMolecules_get_compound, and Mcule_get_compound:

  1. Identity resolution — confirm the structure via PubChem CID and canonical SMILES before searching any catalog.
  2. Vendor search — query ZINC (230M+ compounds), Enamine (~4M in stock plus make-on-demand), eMolecules (8M+ across multiple vendors), and Mcule (40M+).
  3. Price and availability comparison — collate pricing, purity grade, stock status, and delivery timelines.
  4. Analog search — when nothing exact is purchasable, find structurally similar in-stock alternatives at Tanimoto ≥ 0.7.
  5. Decision summary — a vendor recommendation with ChEMBL bioactivity context for the compound and any proposed analog.

Purchasing rules the skill applies: in-stock beats cheaper (make-on-demand runs 2–4 weeks); purity floors of ≥ 95% for screening, ≥ 98% for dose-response, and ≥ 99% for reference standards; a listing priced above 5× the median usually signals a different salt form or purity grade, so costs are normalized per mg; and SMILES searches are preferred over name searches because names are ambiguous. Missing purity data, a 4-week “in stock” lead time, or a SMILES mismatch are flagged for vendor confirmation before ordering.

Primary use cases: procuring screening compounds, curating a purchasable virtual library, sourcing analogs for a SAR series.

Notes

It is a reasoning layer over ToolUniverse; without the MCP server registered, the tool calls fail. Prices and stock status are whatever the vendor catalogs report at query time — treat them as a shortlist to confirm with the supplier, not a quote.

Deeper on procurement than the commercial-availability phase of Small Molecule Discovery, which covers the same vendors in one step as part of a broader compound workup. Complements the standalone ZINC, PubChem, and ChEMBL entries, and pairs with SAR Analysis when the goal is buying out an analog series. ToolUniverse ships ~68 such skills; other workflows are catalogued separately.

Sources

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