MCP Trace vs Spanlens
A side-by-side look at the MCP Trace and Spanlens MCP servers: transport, auth, tools, quality signals, and the config to install either one in Claude, Cursor, Windsurf or VS Code.
M
MCP TraceMonitoringQuery OpenTelemetry traces from agent runs through MCP.47FairAuth: no auth requiredVerdict: choose MCP Trace for monitoring work; choose Spanlens for monitoring as a local process. You can also run both side by side in one mcpServers block.
Which MCP server should you choose?
MChoose MCP Trace when
- You need dedicated capabilities in the Monitoring domain.
- Its auth model fits you: No auth required.
- You want tools like
list_runs, run_summary, span_tree.
Choose Spanlens when
- You need dedicated capabilities in the Monitoring domain.
- You prefer a local stdio subprocess transport.
- Its auth model fits you: API key required.
- You have the keys it needs:
SPANLENS_API_KEY.
Feature & specification comparison
Rows where the two servers differ are marked.
| Spec | M MCP Trace | |
|---|---|---|
| Category | Monitoring | Monitoring |
| Quality signal | 47/100 · Fair | 59/100 · Good |
| Install command | Not confirmed yet | Confirmed |
| Transport | — | Local subprocess (stdio) |
| Auth | No auth required | API key required |
| Pricing | Free | Free |
| Required env vars | None listed | SPANLENS_API_KEY |
Tools & capabilities
MCP Trace tools 12
list_runsStarting out — recent runs with task, model, duration, cost, decision countsrun_summaryOne run at a glance (accepts trace-id prefix)span_tree"What did the agent actually do?" — nested shape of the runslowest_spans"Why was it slow?" — top-k spans by durationapproval_logHITL audit — every approve/deny/**edit**, who decided, and *the rationale*token_usageCost questions — aggregated across runs or per-runsearch_spansFind spans by tool name, file path, "denied", …failure_reportFind actionable, bounded, redacted errors and failed tool calls.tool_statsRank tools by volume, error rate, denials, and latency.security_auditAudit caller identity, tenant, server provenance, risk, and approval evidence.recent_activityPoll new spans with a cursor while a run is active.compare_runsCompare selected traces for regressions across models or versions.
Spanlens tools
No tool names declared yet. Check the project README from the listing page.
Ready-to-paste client configs
Paste either block (or both) into your client config, e.g. claude_desktop_config.json or ~/.cursor/mcp.json. We only show a config when the install command is confirmed.
MCP Trace
No confirmed install command for MCP Trace yet — follow the setup steps linked from its listing page rather than a guessed package name.
Spanlens
{
"mcpServers": {
"spanlens-spanlens-2": {
"command": "npx",
"args": [
"-y",
"@spanlens/cli"
],
"env": {
"SPANLENS_API_KEY": "YOUR_SPANLENS_API_KEY_HERE"
}
}
}
}
Frequently asked questions
MCP Trace is categorized under Monitoring and uses an install path we have not confirmed yet. Spanlens belongs to Monitoring and uses a local stdio subprocess. Pick MCP Trace for monitoring work and Spanlens for monitoring.
Copy the mcpServers block from the config section on this page into your client's config (for example claude_desktop_config.json or ~/.cursor/mcp.json), then fully restart the client. MCP Trace has no confirmed install command yet — follow its own setup instructions.
MCP Trace is listed as free. Auth: no auth required. Spanlens is listed as free. Auth: api key required. If a server needs environment variables such as API keys, define them under the env key in your client's MCP config.
Yes. MCP clients support multiple servers: add mcp-trace and spanlens-spanlens-2 as separate keys in the same mcpServers object, and your assistant will call tools from either one.
On AllMCPs, MCP Trace has a quality signal of 47/100 (Fair) with 0 views, 0 installs and 0 GitHub stars. Spanlens has 59/100 (Good) with 4 views, 0 installs and 13 GitHub stars.
