io.github.xyzzylabs/tc39-mcp
tc39-mcp
io.github.xyzzylabs/tc39-mcp costs 1 997 tokens of context per session. It has 17 tool definitions. That is 1.0 % of a 200k window. Measured 2026-10-03.
Independent MCP server for the TC39 specs (ECMA-262 + ECMA-402): clauses, search, diffs, history.
alive probed 2026-10-03 · HTTP 200
17tools
2.0ktokens for the tool definitions
1.0 %of a 200k context window
299 msto initialize
441 msto list tools
- Endpoint
- https://mcp.xyzzylabs.ai/tc39/mcp (streamable-http)
- Host
- mcp.xyzzylabs.ai
- Protocol
- 2024-11-05
- Reports itself as
- tc39-mcp 0.6.3
- Capabilities
- prompts, tools
- Instructions
- 2 346 characters
- Repository
- https://github.com/xyzzylabs/tc39-mcp
- Website
- https://mcp.xyzzylabs.ai/tc39
- Registry
- active, updated 2026-09-08 · registry entry
- Reachable
- 2 of the last 2 probes
Most expensive tools
| Tool | Tokens | Share of this server |
|---|---|---|
| spec.crossrefs | 208 | 10 % |
| clause.get | 151 | 8 % |
| spec.grammar | 140 | 7 % |
| test262.search | 138 | 7 % |
| spec.sdo_index | 130 | 7 % |
History
We add a row when the result changes. A server with no change keeps its last row.
| Probed | Result | Init | Tools | Tokens |
|---|---|---|---|---|
| 2026-10-03 20:40 | alive | 299 ms | 17 | 2.0k |
| 2026-10-03 17:55 | alive | 232 ms | 17 | 2.0k |
Badge
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