SKILL 19 / RESEARCH · ROUNDUP

Research Skills: Ten You Can Actually Install

Retrieval layer / process layer / posture layer — and why strong research skills leave an audit trail

2026-09-20 · BigCat

Research is the category most easily faked by looking like research: numbered citations, confidence markers, a counter-evidence section. Format reads as credible far more readily than content does. All ten items below open in a browser, and the test is single: does it leave behind something you can check afterwards?

Prerequisite → Skill 9 MCP Servers Roundup (the general ledger for items 6-10)

// WHY THIS MATTERS

Writing has no oracle. Research has half of one: whether a citation opens, whether the date is right, whether the sentence is actually what that source said — a machine can settle the first two. So the real divide in this category is not who writes the deepest report, but who leaves a second, checkable ledger alongside it: a citation registry, source-type labels, and the sources that were dropped along with why. Install commands below are copied from each project's own page. Section 02 explains why these ten belong to three layers and cannot be compared as one list, section 03 gives six things you can check in three minutes with SKILL.md open, and section 04 lays out the costs.

// 01

The list first: ten rows, installs below

Claim: read columns two and three across. Failures in this category almost all come from installing two process-layer skills and zero retrieval — the skill governs the procedure tightly, but the eyes it calls are still the default ones.
Item From What it takes off your hands When not to install ────────────────────────────────────────────────────────────────────────────────────────────────────────────── 1 deep-research trio daymade/claude-code-skills Citation registry, frozen You just want an answer 2 claude-deep-research-skill 199-biotechnologies 8 phases + 2 check scripts You want no Python deps 3 Deep-Research-skills Weizhena Outline first, you approve You hate being stopped 4 agent-research-skills lingzhi227 31 skills, whole paper cycle You write no papers 5 discernment-nudge anthropics/skills 3 questions on what to verify You want answers only 6 paper-search-mcp openags 20+ academic sources at once You search web, not papers 7 arxiv-mcp-server blazickjp Papers on disk + BibTeX You keep no local archive 8 exa-mcp-server exa-labs Web search in 2 tool slots You have another retriever 9 firecrawl-mcp-server firecrawl Crawling + change monitoring You only wanted a search 10 tavily-mcp tavily-ai search / extract / map / crawl You never traverse a site ────────────────────────────────────────────────────────────────────────────────────────────────────────────── 1-4 are four implementations of the process layer; pick one. 6-10 are retrieval; pick one or two. 5 goes with anything.

How to install (commands copied from each project's own page)

# 1 — 59 directories in that repo. Copy the two or three you want, not all of it.
/plugin marketplace add daymade/claude-code-skills
git clone --depth 1 https://github.com/daymade/claude-code-skills /tmp/dcs
cp -r /tmp/dcs/deep-research /tmp/dcs/competitors-analysis /tmp/dcs/fact-checker ~/.claude/skills/

# 2 — note: also named deep-research, same target directory as 1. Pick one.
git clone https://github.com/199-biotechnologies/claude-deep-research-skill.git ~/.claude/skills/deep-research

# 3 — clone the repo first, then copy. English and Chinese sets, plus Codex / OpenCode variants.
cp -r skills/research-en/* ~/.claude/skills/
cp agents/web-search-agent.md ~/.claude/agents/
cp -r agents/web-search-modules ~/.claude/agents/
pip install pyyaml

# 4 — pulls in 31 skills at once. Worth it only if you write papers.
npx skills add lingzhi227/agent-research-skills -g -a claude-code

# 5 — official, and a plugin of its own: it is not inside example-skills.
/plugin marketplace add anthropics/skills
/plugin install discernment-nudge@anthropic-agent-skills

# 6 — one project, two forms. This is the skill install; MCP install is in the repo.
uv tool install paper-search-mcp
mkdir -p ~/.claude/skills/paper-search
curl -fsSL https://raw.githubusercontent.com/openags/paper-search-mcp/main/claude-code/SKILL.md \
  -o ~/.claude/skills/paper-search/SKILL.md

# 7-10 — the retrieval layer. Pick one, at most two.
uvx arxiv-mcp-server                                   # 7 into mcpServers; papers land in ~/.arxiv-mcp-server/papers
claude plugin install exa@claude-plugins-official      # 8 two tools by default
env FIRECRAWL_API_KEY=fc-YOUR_API_KEY npx -y firecrawl-mcp   # 9 twenty-five tools by default
npx -y tavily-mcp@latest                               # 10 four tools, API key required

# Do this immediately after installing
/skill-doctor    # context cost and invocation frequency per skill

Item by item

Further resources · anthropics/skills directory (check real names against repo directories; aggregator sites get them wrong often)
// 02

Why these ten do not compare: three layers, not one row

Claim: retrieval decides what you can get, process decides what trail you leave, posture decides how you receive the conclusion. They complement each other, and almost everyone installs only the middle one.
Posture 5 discernment-nudge -> makes you look back once it has answered ^ Process 1-4 deep-research family -> decompose, dispatch, register, counter-check ^ (it does not go online by itself) Retrieval 6-10 MCP servers -> where web / paper / whole-site bytes come from

One common install is simply wrong: items 1 and 2 together. Both target ~/.claude/skills/deep-research, so the names collide; and even after you rename a directory, the two descriptions compete for the same trigger ("research this topic", "write a report on"), so which procedure runs is a coin flip. Pick exactly one process-layer skill. That one is not negotiable.

The reverse is more common still: a carefully chosen process layer and no retrieval at all. Item 1's rule about reopening originals for load-bearing claims then lands on default web search, which surfaces the same aggregator pages as before. No procedure is stricter than the eyes it calls. Papers mean items 6 and 7; watching a competitor's site means item 9's firecrawl_monitor_*; wanting accurate search without burning tool slots means item 8.

Item 4 is a third kind of thing: not general research but a disciplinary pipeline. Pointed at market research it feels wrong, because rebuttal-writing and latex-formatting will never fire in that context while still costing description budget every turn. The test is easy: does your output carry a bibliography? If yes, install it; if no, do not.

What failure looks like: items 1, 2 and 3 installed together, three process layers taking turns on one trigger, and not a single retrieval server. The symptom is "every report comes out in a different shape, but the citations are always the same three aggregators" — that is not a weak model, that is three procedures all pointed at one pair of eyes.
// 03

Three-minute check: six things to look for in SKILL.md

Claim: research is luckier than writing — it has half an oracle. Whether a citation opens and whether a date is right are machine-checkable. So every criterion here circles one question: does this thing leave a ledger you can audit afterwards?
  1. Is there a citation ledger separate from the prose? Item 1 builds one at P3 — numbered, deduplicated, and recording dropped sources with the reason they were dropped — and the draft may cite only from it once frozen. Without that layer, citations are decoration on the prose: you cannot audit what it used or what it threw away.
  2. Does uncertainty have an exit? Look for [Unverified], confidence markers, an explicit "say you could not find it". A research skill that is not allowed to output "I do not know" will encode uncertainty as certainty, because you left it only one exit.
  3. Is there a dating convention? Item 1 fixes AS_OF at P0 and requires a source date on every time-sensitive claim. Without it, last year's figure and this year's get written into the same sentence as equals.
  4. Is there a check a machine can run? Item 2's verify_citations.py tests whether a DOI or URL exists; validate_report.py runs nine checks. This is the only thing in the category that catches errors without reading the content. Mind its boundary, though — see section 04.
  5. Where can a human intervene? Item 3 makes outline approval a blocking first phase. The most expensive research error is direction, and direction is only cheap to fix in the first few minutes. A skill that involves you only at "please review the report" has no gate at all.
  6. What tools does it assume you have? The easiest one to miss. Read what retrieval the SKILL.md refers to: bundled scripts (item 4's four academic APIs, item 2's search-cli), or an MCP server it assumes you already installed? When that assumption fails it does not error — it degrades quietly.

If three of these six have no answer, what you have bought is the layout of research, not research.

// 04

The honest costs: where it is expensive, and where it fools you

Claim: research is the most expensive skill category, and expensive in ways you do not see — tokens burn inside subagents you never read, and trust burns on the single impression that it looked thorough.

Money

Anthropic published its own numbers: per its engineering post "How we built our multi-agent research system", 2025-06, Research runs an orchestrator-worker pattern — a lead agent plans, spawns subagents that work in parallel with their own context windows, and merges their findings with a separate citation pass. The return was a 90.2% improvement on their internal research eval for an Opus 4 lead with Sonnet 4 subagents; the price is roughly 15x the tokens of an ordinary chat interaction, and the same post is explicit that this architecture is a poor fit for tightly interdependent work such as coding. Items 1 and 2, with their lead-plus-subagents structure, spend exactly that. Budget a deep report like a compile, not like a question.

Tool slots

Item 9 ships 25 tool definitions by default; item 8 ships 2. Those definitions sit in context every turn whether or not you use them. Count tools before installing a second retrieval server — and the same arithmetic applies to item 1's 59 directories and item 4's 31 skills, where a bulk install is a description tax paid each turn. Run /skill-doctor afterwards: it reports the context cost and invocation frequency of every skill you have.

Where it fools you

Citation verification is not fact verification. verify_citations.py can confirm that a DOI exists and a URL resolves, but it does not check whether the sentence is what that source said. A link that is real, numbered neatly, and does not actually support the claim attached to it is this category's most frequent false positive — and it passes every automated check by construction.

The second trap is that format reads as more credible than content. Numbered citations, confidence markers and a "counter-evidence" section are all visual signals of rigor. A skill that only applies the layout, without ever reopening an original, produces something indistinguishable on screen from real work. The six criteria in section 03 are, at bottom, one question asked six ways: is there a ledger behind this layout?

Third, nearly all of these default to the open web, so second-hand aggregators get treated as sources — Skill 21 on this site takes that apart on its own.

// ONE-PAGE BUYING CARD

Install these three first: deep-research from daymade/claude-code-skills (copy that one directory, not all 59; you are buying the P3 citation registry and the [Unverified] exit) + exa-mcp-server (claude plugin install exa@claude-plugins-official, two tool slots, a decent pair of eyes for the process layer) + discernment-nudge (/plugin install discernment-nudge@anthropic-agent-skills, official, lightest here, fires once per conversation).

Add as needed: openags/paper-search-mcp (papers, most sources key-free) · blazickjp/arxiv-mcp-server (when you want BibTeX and papers archived on disk) · Weizhena/Deep-Research-skills (swap it in for the process layer above when you want a human gate at the outline) · 199-biotechnologies/claude-deep-research-skill (when you want checks that actually run, like verify_citations.py) · item 9's firecrawl_monitor_* (when you really are watching a competitor's site) · tavily-mcp (site map and crawl without twenty-five tools) · lingzhi227/agent-research-skills (when you genuinely write papers).

Explicitly do not install: items 1 and 2 at once (same ~/.claude/skills/deep-research directory, same trigger) · a process layer with no retrieval server at all (a strict procedure wired to default eyes) · firecrawl-mcp's 25 tools for a one-off search · all 31 skills of agent-research-skills when you write no papers.

Three things after installing: run /skill-doctor and count tool slots and context cost · walk your chosen process layer through the six checks in section 03 · set yourself one floor — for any number you will act on, open the citation yourself.

// GLOSSARY

citation registry
A source list kept separate from the prose: deduplicated, numbered, with dropped sources and reasons recorded. Once frozen, the draft cites only from it. The first criterion in this issue.
evidence family
Several reports derived from one filing or one study count as a single source. Not collapsing them turns one source into five and manufactures fake corroboration.
AS_OF
The cutoff date fixed at the start of a research run. Every time-sensitive claim carries its source date, so last year's figure is not silently read as this year's.
orchestrator-worker
A lead agent decomposes the task across subagents with independent context windows, then merges results. The standard deep-research architecture, and the origin of the 15x token figure.
tool-slot budget
Every MCP server's tool definitions sit in context permanently. Exa ships 2 by default, Firecrawl 25 — the number that actually matters when choosing a retrieval layer.

// FURTHER READING