A MartenDB specialist for the Marten document database library for C#. It uses a dedicated documentation server and retrieves only focused sections.

Use it for Marten APIs and concepts such as document sessions, queries, projections, event stores, compiled queries, and indexing.

It helps answer Marten questions from relevant documentation without loading large, unrelated document collections.

martendb — Skill for Claude Code and Codex by stijnVanHorenbeek

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add stijnVanHorenbeek/marten_mcp --skill martendb

Clone the repo

git clone --depth 1 https://github.com/stijnVanHorenbeek/marten_mcp

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/stijnvanhorenbeek/marten_mcp/martendb/github.svg)](https://agentmods.dev/skills/stijnvanhorenbeek/marten_mcp/martendb)

Your own site

<a href="https://agentmods.dev/skills/stijnvanhorenbeek/marten_mcp/martendb"><img src="https://agentmods.dev/badge/skills/stijnvanhorenbeek/marten_mcp/martendb/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/stijnvanhorenbeek/marten_mcp/martendb"><img src="https://agentmods.dev/badge/skills/stijnvanhorenbeek/marten_mcp/martendb.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 58 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 300 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00058	$0.00300
Opus 5.5	$0.00023	$0.00120
Sonnet 5.5	$0.00012	$0.00060
Haiku 4.5	$0.00006	$0.00030

Measured 2mo ago against content hash 87a494a435b4, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

martendb scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

examples/skills/martendb/SKILL.md · 27 lines

What it actually says

MartenDB Expert

Use the marten-docs MCP server for Marten documentation.
Do not fetch bulk doc dumps or alternate mirrors unless the MCP server is unavailable.
Keep retrieval narrow and minimal.

Retrieval pattern

Start with search_docs(query, limit=3).
Narrow within a page using one of:
- list_headings(path)
- search_within_page(path, query, limit=3)
Use read_context(id, before=1, after=1) only to inspect nearby chunk refs.
Read content with read_section(id, offset=0, maxChars=1200).
Continue with offset=nextOffset only when hasMore=true.

Rules

Do not use broad page reads or bulk retrieval.
Prefer continuing from a good hit over running repeated similar searches.
If the user mentions a specific Marten version, include it in the query and answer against that version.
If version behavior is unclear, say the answer is based on current indexed docs.
Separate documented Marten behavior from your own implementation advice.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 27 lines · 58 tokens per session scan A 87a494a435b4

Subscribe to this mod's changes

martendb is a skill published in the GitHub repository stijnVanHorenbeek/marten_mcp (0 stars, last pushed 7mo ago), licensed MIT. It adds 58 tokens to every session and 300 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Databases

martendb next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
martendbstijnVanHorenbeek/marten_mcp	Skill	0	7mo ago	MIT	A	58	Claude Code, Codex
create-prprisma/orm	Skill	48k	yesterday	Apache-2.0	A	48	Claude Code, Codex
schema-explorationlangchain-ai/deepagents	Skill	31k	yesterday	MIT	A	57	Claude Code, Codex
atlas-mssqlariga/atlas	Skill	8.8k	2d ago	Apache-2.0	A	163	Claude Code
ha-data-storesshiwenwen/hope-agent	Skill	1.9k	yesterday	MIT	A	115	Claude Code, Codex
nornicdb-cypher-queriesorneryd/NornicDB	Skill	924	yesterday	MIT	A	79	Claude Code, Codex
volcengine-rds-postgresqlbytedance/agentkit-samples	Skill	484	2d ago	Apache-2.0	A	63	Claude Code, Codex