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【Project】How We Build the Deep Research Skill

Sep 19, 20261 min
TL;DRThis is the project's own deep research skill design, fully disclosed. Core choices: only Groundlane MCP for web tools, strict source-quality grading (A/B/C/D), research hands off to post skill for publishing. Not the most powerful, but the best fit for us.

🌏 中文版

The previous 12 articles covered other people's research. This one covers ours.

The project's deep-research skill has been iterated since March 2026. This article tears it open: design philosophy, architectural choices, tool boundaries, and why.

Core Design Philosophy

Tool Boundary: Strictly Groundlane Only

This is the most distinctive design choice in the project skill:

All public web research uses only Groundlane MCP (web_search / web_fetch / web_extract). No Tavily, Exa, Firecrawl, Jina, or Linkup.

Why?

  1. Control: Groundlane is a self-maintained MCP server—we control providers, rate-limiting, and authorization
  2. Consistency: All research goes through the same pipeline, behavior is predictable
  3. Cost: Self-hosted provider keys, no per-tool fees
  4. Auditable: All requests through a single entry point, easy to debug

Groundlane itself:

  • Author: vincentxuu
  • Type: Vendor-neutral remote MCP server
  • Providers: Tavily, Exa, Parallel, Browserbase, Brave, Firecrawl, SerpApi, Linkup, Serper, You.com
  • Deployment: Cloudflare Workers + Containers

Output Goal: Research Note → Post Publishing

Not all research gets published. The project skill distinguishes:

OutputStoragePurpose
Research note.research/<YYYY-MM-DD>-<slug>.mdWorking backup, not version-controlled
Published articlesrc/content/posts/<category>/Final article

Flow: deep-research → research note → post skill → bilingual article

This means the research phase doesn't pollute version control—only confirmed-to-publish articles go in.

The 7-Step Workflow

0. Multi-case research (if topic is a series/comparison)
1. Decompose research sub-questions
2. Gather (≥2 sources per sub-question)
3. Catalog reading completeness
4. Cross-verify
5. Extract structure
6. Produce research note
7. Hand off (to post skill for publishing)

Key Discipline

  1. Decompose before searching—wrong questions are more expensive than wrong answers
  2. Bring full text of primary sources—not just query results (queries return snippets)
  3. Cross-table only shows "what sources said"—inference is labeled separately
  4. Numbers with conditions—effect sizes without control conditions are unusable
  5. List conflicting facts—don't pick sides

Source Quality Grading

General Source Tiers

TierDefinitionExamples
A — Official PrimaryPublished by creator/maintainerOfficial docs, release notes, GitHub README
B — First-hand AuthorAuthor's informal publicationsAuthor's X/Mastodon, personal blog, talks
C — High-quality SecondaryThird-party with independent verificationHN top threads,知名 blog with testing
D — Low-quality SecondaryNo independent verificationMedium reprints, SEO blogs, AI summary sites

Academic Paper Quality

Hard indicators: Conference tier (NeurIPS/ICLR/ACL), citation count, institutional prestige Soft indicators: Real benchmarks run, reproducibility, cited by later work, survey's taxonomic insight

Paper Quality Tiers

  • Tier A: Tier-1 conference accepted, >200 citations with open-source code,知名 AI lab with experimental data
  • Tier B: Tier-2 conference, >100 citations,知名 institutions
  • Tier C: arXiv preprint, <50 citations

Companion Skill Ecosystem

SkillRole
deep-researchCore research workflow
research-selectionMulti-case selection (population → coverage matrix → bias)
postPublish after research (bilingual)
post-reviewPre-publishing self-review
post-verifyFact-layer verification
series-curriculum-designSeries planning

This ecosystem forms a pipeline: research → selection → publishing → review → verification.

Design Trade-off Reflections

Why No Adversarial Verification?

External skills (jamoeight v2, tolmachevmaxim) almost all have adversarial verification (Optimist/Pessimist/Fact-Checker). We don't.

Reasons:

  • Adversarial verification needs multiple models, increasing cost
  • Cross-verification (≥2 independent sources) is sufficient in most cases
  • Adversarial verification suits "controversial claims" but deep research is more about "synthesis tasks"

Why No Persistent Knowledge Base?

External skills (hyperresearch) have SQLite-indexed persistent research knowledge. We don't—each session is independent.

Reasons:

  • Persistence requires storage management, increasing complexity
  • Most project research is one-off tasks, no cross-task retrieval needed
  • If needed later, .research/ directory provides basic search

Why Bind to Groundlane?

This is the most controversial design. External skills widely use Tavily, Exa, Serper etc.

Reasons covered above (control, consistency, cost, auditability). But the cost: if Groundlane breaks, the entire pipeline stalls.

Improvement Directions

  1. Adversarial verification module: Add Pessimist/Fact-Checker agents
  2. Persistent knowledge base: .research/source-registry.jsonl for cross-task indexing
  3. MCP expansion: Beyond Groundlane, add GitHub, arXiv, Hugging Face dedicated tools
  4. Automation: Semi-automated from research note to post

References