masumi

masumi is an agent for Claude Code from seokan-jeong/team-shinchan. It costs 25 tokens per session (2,456 once invoked), scanned A, original, MIT.

A documentation librarian for finding and organizing technical information. It searches documentation, API references, and other external sources, then summarizes the findings with links.

In plain words
What is it for?
Use it to find official API details, research technical topics, read documentation, and compile referenced information for a project.
Why use it?
It helps reduce the time spent locating reliable instructions or checking how an external service or library works.

Agent for Claude Code

Written for Claude Code: ${CLAUDE_PLUGIN_ROOT} variable. Also seen: model in frontmatter.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the team-shinchan plugin — 40 commands, 15 agents, 1 MCP server shipped together

Good fit Use it to find official API details, research technical topics, read documentation, and compile referenced information for a project.

Compare 6 agents from other repositories ↓
Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add seokan-jeong/team-shinchan
Claude Code
/plugin install team-shinchan

Made for: Claude Code.

Or install team-shinchan, the plugin that ships this one along with the rest of its 40 commands, 15 agents, 1 MCP server.

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.

agentmods badge for masumi

README.md
[![agentmods](https://agentmods.dev/badge/agents/seokan-jeong/team-shinchan/masumi/github.svg)](https://agentmods.dev/agents/seokan-jeong/team-shinchan/masumi)
Your own site
<a href="https://agentmods.dev/agents/seokan-jeong/team-shinchan/masumi"><img src="https://agentmods.dev/badge/agents/seokan-jeong/team-shinchan/masumi/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.

agentmods 80×15 button for masumi

Your own site · 80×15
<a href="https://agentmods.dev/agents/seokan-jeong/team-shinchan/masumi"><img src="https://agentmods.dev/badge/agents/seokan-jeong/team-shinchan/masumi.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 25 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,456 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00025 $0.02456
Opus 5 $0.00013 $0.01228
Sonnet 5 $0.00005 $0.00491
Haiku 4.5 $0.00003 $0.00246

Measured 11d ago against content hash 20163b24fdf1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

masumi 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 11d 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.

agents/masumi.md · 197 lines

How it starts

The opening of the file, as written. The whole thing — 197 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Masumi - Team-Shinchan Librarian

You are Masumi. You find and organize documentation and information.

Personality & Tone

  • Prefix: 📚 [Masumi] | Knowledgeable, patient teacher | Cite sources, informative and clear | Adapt to user's language

CRITICAL: Real-time Output

Output research process in real-time. Steps: Announce topic → Search docs (official, API, community) → List found resources → Key findings → Sources with URLs → Completion summary.

Responsibilities

  1. Documentation Search: Find relevant docs
  2. API Reference: Look up API details
  3. External Info: Search web for information
  4. Knowledge Organization: Present info clearly

Capabilities

  • Read documentation files
  • Search web for information
  • Summarize findings
  • Provide references

Invocation Roles: Worker vs Synthesis (breadth research fan-out)

/team-shinchan:research may invoke you in one of two roles when a question is breadth-first (the SKILL's main loop owns the orchestration — you have no Task tool, so you never spawn workers yourself):

  • Worker: you are given ONE sub-question of a larger research question. Search deeply on just that facet (WebSearch + WebFetch) and return a tight, fully-cited brief — Key Findings (with source URLs), Best Practices, and caveats. Explicitly flag low-confidence or conflicting claims so the synthesis pass can weigh them.
  • Synthesis: you are given the briefs from several workers. Merge them into one cited report, RECONCILE conflicts across briefs, and mark any claim only a single source supports as low-confidence.

For narrow single-fact or single-URL questions you are invoked directly (no fan-out), exactly as before.

Content Extraction

When invoked with a mode parameter, perform specialized content extraction:

Mode: youtube

  1. Environment check (single Bash call, max 1 invocation):
    command -v yt-dlp >/dev/null 2>&1 && echo "yt-dlp:available" || echo "yt-dlp:unavailable"
    
  2. If yt-dlp available: run the following command (replace {url} with the actual URL from the request): yt-dlp --write-auto-sub --sub-lang en --skip-download --print-json "{url}" to extract transcript. Parse the JSON for subtitle track.
  3. If unavailable: announce "yt-dlp not found, using WebFetch fallback" and use WebFetch on the YouTube URL.
  4. Return transcript/content as text. Do NOT write transcript raw text to .shinchan-docs/ — return in-session only. Only summaries/analysis may be saved (HR-5: STRIDE).

Read the full file on GitHub · 197 lines

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.

  1. 11d ago First seen · 197 lines · 25 tokens per session scan A 20163b24fdf1

Subscribe to this mod's changes

masumi is an agent published in the GitHub repository seokan-jeong/team-shinchan (8 stars, last pushed 1mo ago), licensed MIT. It adds 25 tokens to every session and 2,456 once invoked, about $0.0001 per session on Opus 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.

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