Candor vs Marrow
A side-by-side look at the Candor and Marrow MCP servers: transport, auth, tools, quality signals, and the config to install either one in Claude, Cursor, Windsurf or VS Code.
Verdict: choose Candor for biology & bioinformatics work as a local process; choose Marrow for biology & bioinformatics as a local process. You can also run both side by side in one mcpServers block.
Which MCP server should you choose?
Choose Candor when
- You need dedicated capabilities in the Biology & Bioinformatics domain.
- You prefer a local stdio subprocess transport.
Choose Marrow when
- You need dedicated capabilities in the Biology & Bioinformatics domain.
- You prefer a local stdio subprocess transport.
- Its auth model fits you: API key required.
- You want tools like
health_summary, list_metrics, metric_daily.
Feature & specification comparison
Rows where the two servers differ are marked.
| Spec | ||
|---|---|---|
| Category | Biology & Bioinformatics | Biology & Bioinformatics |
| Quality signal | 45/100 · Fair | 55/100 · Good |
| Install command | Confirmed | Confirmed |
| Transport | Local subprocess (stdio) | Local subprocess (stdio) |
| Auth | Not declared | API key required |
| Pricing | Not declared | Free |
| Required env vars | None listed | None listed |
| Verified owner | Community listing | Community listing |
| GitHub stars | 1 | 3 |
| Directory activity | 2 views 0 installs 0 upvotes | 3 views 0 installs 0 upvotes |
| Tools | Not listed | 9 |
| Full listing | View Candor | View Marrow |
Tools & capabilities
Candor tools
No tool names declared yet. Check the project README from the listing page.
Marrow tools 9
health_summaryRecent days across activity, heart, sleep and nutritionlist_metricsEvery metric in the mirror, with units and coveragemetric_dailyDaily values for any metric, up to 400 daysmetric_samplesRaw records with timestamps and source devicesworkoutsWorkouts from every source: activity, start, end, duration and sourcenutrition_logThe meal diary: every logged food with full nutrient detail, by daystrength_logEvery lifting set with its set type and estimated 1RM, per-exercise progression, and volume per muscle group (warm-ups left out)sleep_logOne night per wake day: bedtime, wake time, hours asleep, minutes per stagesymptoms_and_moodSymptoms with their severity, and State of Mind entries with valence, feelings and what they were about
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.
Candor
{
"mcpServers": {
"candor": {
"command": "npx",
"args": [
"-y",
"candor-ts"
]
}
}
}
Marrow
{
"mcpServers": {
"marrow-4": {
"command": "uvx",
"args": [
"--from",
"marrow-mcp",
"marrow-server"
]
}
}
}
Frequently asked questions
Candor is categorized under Biology & Bioinformatics and uses a local stdio subprocess. Marrow belongs to Biology & Bioinformatics and uses a local stdio subprocess. Pick Candor for biology & bioinformatics work and Marrow for biology & bioinformatics.
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.
Candor has no declared pricing — check the project's own site. Marrow 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 candor and marrow-4 as separate keys in the same mcpServers object, and your assistant will call tools from either one.
On AllMCPs, Candor has a quality signal of 45/100 (Fair) with 2 views, 0 installs and 1 GitHub stars. Marrow has 55/100 (Good) with 3 views, 0 installs and 3 GitHub stars.