Skip to main content
Watch: I Built an AI App Without Leaving Databricks

AI and ML platforms - official Weights & Biases server

W&B MCP server

Lets MCP clients query Weights & Biases runs, Weave traces, evaluations, artifacts and registries in natural language, create W&B reports, and search the W&B documentation. Available as a W&B-hosted HTTP server or run locally over STDIO or HTTP. Weights & Biases hosts it at https://mcp.withwandb.com/mcp, or you can run git+https://github.com/wandb/wandb-mcp-server (git) locally with API key auth.

Last verified 15 tools6 sources

Install

Claude Code

About Claude Code
Terminal
claude mcp add --transport http wandb https://mcp.withwandb.com/mcp \
  --header "Authorization: Bearer [YOUR-WANDB-API-KEY]"

Codex

About Codex
Terminal
export WANDB_API_KEY=[YOUR-WANDB-API-KEY]
codex mcp add wandb \
  --url https://mcp.withwandb.com/mcp \
  --bearer-token-env-var WANDB_API_KEY

Cursor

About Cursor
JSON
{
     "mcpServers": {
       "wandb": {
         "transport": "http",
         "url": "https://mcp.withwandb.com/mcp",
         "headers": {
           "Authorization": "Bearer [YOUR-WANDB-API-KEY]",
           "Accept": "application/json, text/event-stream"
         }
       }
     }
}

VS Code

JSON
{
  "servers": {
    "wandb": {
      "type": "http",
      "url": "https://mcp.withwandb.com/mcp",
      "headers": {
        "Authorization": "Bearer [YOUR-WANDB-API-KEY]"
      }
    }
  }
}

Generic

JSON
{
  "mcpServers": {
    "wandb": {
      "command": "uvx",
      "args": [
        "--from",
        "git+https://github.com/wandb/wandb-mcp-server",
        "wandb_mcp_server"
      ],
      "env": {
        "WANDB_API_KEY": "[YOUR-WANDB-API-KEY]",
        "WANDB_BASE_URL": "https://your-wandb-instance.example.com"
      }
    }
  }
}

Tools

list_entities_tool
List the teams and accounts the API key can reach
query_wandb_entity_projects
List projects for an entity
probe_project_tool
Discover metrics, config keys and tags in a run-based project
infer_trace_schema_tool
Discover field names, types and sample values in a Weave traces project
query_wandb_tool
Query runs, sweeps, configs, summaries or artifacts via structured reads or a bounded query-only GraphQL document
get_run_history_tool
Bounded time-series metric history for a run
compare_runs_tool
Config diff, metric deltas and aligned history across runs
diagnose_run_tool
Check whether a run converged, is overfitting or hit NaN values
query_weave_traces_tool
Query LLM traces with schema, summary or full detail levels
count_weave_traces_tool
Count traces and errors without fetching trace data
resolve_trace_roots_tool
Map child traces back to their root sessions in one batched call
summarize_evaluation_tool
Summarize evaluation pass rates and failing tasks
create_wandb_report_tool
Create a W&B report with Markdown and chart panels
log_analysis_to_wandb
Persist analysis values computed in the session as a W&B run
search_wandb_docs_tool
Search the official W&B documentation

As documented on October 17, 2026. A running server reports its current list through tools/list.

Notes and caveats

  • docs.wandb.ai now redirects to docs.coreweave.com (W&B is part of CoreWeave); API keys are created at forge.coreweave.com.
  • Dedicated Cloud and Self-Managed use https://[YOUR-INSTANCE]/mcp once the operator enables it.
  • The hosted server follows the main branch.
  • The repo's release index lists 0.4.3 as a candidate with release date 'Pending' and no signed source release, so no release date is given.
  • The docs also show 'pip install wandb-mcp-server', but no such package resolved on PyPI on 2026-10-17; install from the GitHub URL.
  • Claude Desktop needs the mcp-remote proxy for API-key auth to the hosted server.
  • Some tools (ARIA, Agent Lens, Weave Agents OTel) are only exposed in specific tool profiles; WANDB_MCP_ACCESS_MODE=read-only removes write tools.

More MCP servers for AI and ML platforms

Related reading

FAQ

What does the W&B MCP server do?

Lets MCP clients query Weights & Biases runs, Weave traces, evaluations, artifacts and registries in natural language, create W&B reports, and search the W&B documentation. Available as a W&B-hosted HTTP server or run locally over STDIO or HTTP. The vendor documents 15 tools, including list_entities_tool, query_wandb_entity_projects, probe_project_tool and infer_trace_schema_tool.

How do I add the W&B MCP server to Claude Code?

Weights & Biases documents a Claude Code config; copy it from the Claude Code section of this page. Snippets for Codex, Cursor, VS Code and Generic are there too.

Does the W&B MCP server need authentication?

Yes, API key. Transport: Streamable HTTP, stdio. Status: GA, last checked October 17, 2026.

Sources

Last verified against 6 Weights & Biases pages, then re-checked independently.

Newsletter

New MCP servers, the week they ship

One email per week. New official MCP servers, the coding tools that support them and how developers wire them up.