io.github.cyanheads/pubchem-mcp-server
pubchem-mcp-server
Search PubChem compounds, properties, safety data, bioactivity, and cross-references.
alive probed 2026-10-15 · HTTP 200
10tools
9.4ktokens in Claude Opus 5.5
9.6ktokens in Claude Code
4.7 %of a 200k context window
5.5ko200k_base estimate
197 msto initialize
87 msto list tools
- Endpoint
- https://pubchem.caseyjhand.com/mcp (streamable-http)
- Host
- pubchem.caseyjhand.com
- Protocol
- 2025-11-25
- Reports itself as
- pubchem-mcp-server 0.7.0
- Capabilities
- logging, prompts, resources, tools
- Instructions
- 1 056 characters
- Claude count
- Claude Opus 5.5, measured 2026-10-15. Counted again when the tool definitions change. Method.
- Repository
- https://github.com/cyanheads/pubchem-mcp-server
- Registry
- active, updated 2026-10-15 · registry entry
- Reachable
- 7 of the last 7 probes
Most expensive tools
| Tool | Tokens (o200k) | Share of this server |
|---|---|---|
| pubchem_search_compounds | 1 208 | 22 % |
| pubchem_get_compound_details | 1 058 | 19 % |
| pubchem_get_bioactivity | 672 | 12 % |
| pubchem_get_compound_interactions | 522 | 9 % |
| pubchem_get_compound_3d_structure | 470 | 8 % |
History
We add a row when the result changes. A server with no change keeps its last row.
| Probed | Result | Init | Tools | Claude | o200k |
|---|---|---|---|---|---|
| 2026-10-15 10:33 | alive | 216 ms | 10 | 9.4k | 5.5k |
| 2026-10-08 11:13 | alive | 360 ms | 10 | 8.0k | 4.6k |
| 2026-10-05 00:33 | alive | 197 ms | 10 | 8.0k | 4.6k |
| 2026-10-04 10:04 | alive | 257 ms | 10 | 4.6k | |
| 2026-10-04 07:57 | alive | 349 ms | 10 | 4.6k | |
| 2026-10-03 20:37 | alive | 879 ms | 10 | 4.6k | |
| 2026-10-03 17:53 | alive | 409 ms | 10 | 4.6k |
Badge and feed
[](https://mcpcost.ulehla.dev/s/io.github.cyanheads/pubchem-mcp-server)
An entry for every probe that changed the result, the tool count or the token cost: Atom feed. Add it to a feed reader or a Slack RSS app to hear when the server stops answering or its tool set grows.