Corroboration Skill Builder

Build students' capacity to compare accounts across multiple historical sources — identifying agreements, contradictions, and gaps.

Context cost
7.5k tokensestimated from the bundle, loaded when it triggers
Bundle
1 file · 29.8 kBtext throughout, nothing executable
Licence
not declarednone named by its author
Last change
—v1.0
Servers it uses
Noneruns standalone

What it does

Build students' capacity to compare accounts across multiple historical sources — identifying agreements, contradictions, and gaps. Use when students treat individual documents as complete answers rather than partial perspectives.

What this skill changes about the agent has not been set out here as a list. Its SKILL.md, shown below, says it in the author’s own words.

corroborationdigdisciplinary-literacydocument-analysisdocumentationevidence-weighinghistorical-thinkingmulti-document-reasoning

The skill itself

A skill is instructions the model reads, so you can see what you are getting: below is the start of its SKILL.md. The front matter loads with every session, the body loads when the skill triggers, and the whole file comes with the install.

SKILL.md29.8 kB · preview
--- # AGENT SKILLS STANDARD FIELDS (v2) name: corroboration-skill-builder disable-model-invocation: false user-invocable: true effort: medium # EXISTING FIELDS skill_id: "historical-thinking/corroboration-skill-builder" skill_name: "Corroboration Skill Builder" domain: "historical-thinking" version: "1.0" contributor: "Sean Hu" evidence_strength: "moderate" evidence_sources: - "Wineburg (1991) — Historical problem solving: cognitive processes in the evaluation of documentary and pictorial evidence" - "Reisman (2012) — Reading like a historian: a document-based history curriculum intervention in urban high schools" - "Wineburg & Reisman (2015) — Disciplinary literacy in history: a toolkit for digital citizenship" - "Wineburg & Martin (2004) — Reading and rewriting history" - "Wineburg, Martin & Monte-Sano (2011) — Reading like a historian: teaching literacy in middle and high school history classrooms" - "Wineburg, Smith & Breakstone (2018) — What is learned in college history classes?" input_schema: required: - field: "historical_topic" type: "string" - field: "student_level" type: "string" - field: "current_challenge" type: "string" optional: - field: "available_documents" type: "string" - field: "source_types" type: "string" - field: "curriculum_framework" type: "string" - field: "prior_instruction" type: "string" output_schema: type: "object" fields: - field: "corroboration_progression" type: "object" - field: "explicit_instruction_sequence" type: "object" - field: "corroboration_prompts" type: "array" - field: "common_failure_patterns" type: "array" - field: "assessment_indicators" type: "object" chains_well_with: - "sourcing-skill-builder" - "close-reading-skill-builder" - "contextualisation-skill-builder" - "historical-thinking-strategy-modelling-guide" - "document-based-lesson-designer" - "historical-document-set-curator" - "historical-thinking-assessment-designer" - "argument-structure-scaffold-generator" teacher_time: "4 minutes" tags: ["corroboration", "historical-thinking", "disciplinary-literacy", "multi-document-reasoning", "evidence-weighing", "document-analysis", "DIG"] ---
78# Corroboration Skill Builder
79
80## What This Skill Does
81
82Designs targeted instruction to develop students' corroboration practice — comparing accounts across multiple sources to identify agreements, contradictions, silences, and gaps, and using these comparisons to establish what is probable rather than accepting any single account as definitive. The output includes a developmental progression, an explicit instruction sequence designed for multi-document reasoning, corroboration prompts, common failure patterns, and assessment indicators.
83
84Corroboration is the most complex of the four historical thinking skills because it is inherently intertextual. Sourcing, close reading, and contextualisation can each be practised on a single document. Corroboration cannot — it requires holding multiple accounts in mind simultaneously and reasoning about the relationships between them. This makes it the hardest to teach and the last to develop. Reisman (2012) found no significant treatment effects for corroboration in her six-month intervention, alongside contextualisation. She attributed this partly to the near-absence of whole-class discussion in treatment classrooms — corroboration may require dialogic instruction (discussion, debate, collaborative comparison) more than the other skills because the reasoning is inherently comparative.
85
86Corroboration also depends on the other three skills as prerequisites. To compare sources productively, students must first be able to source each document (who wrote it and why), close-read each document (what exactly does it claim and how), and contextualise each document (what circumstances shaped it). Without these foundations, corroboration degrades into surface-level observation ("these two accounts say different things") rather than analytical reasoning about WHY they differ and what the differences reveal.
87
88## Evidence Foundation
89
90Wineburg (1991) identified corroboration as one of three core heuristics (alongside sourcing and contextualisation) that distinguished expert historians from novice readers. Historians systematically compared accounts, noting where they agreed and diverged, and used discrepancies as diagnostic tools — a contradiction between two sources was not a problem to resolve by picking the "right" one but a clue that demanded explanation. Why would two observers describe the same event differently? The answer always pointed back to the authors' perspectives, circumstances, and purposes.
91
92Wineburg and Martin (2004) demonstrated corroboration in curricular practice through the Pocahontas unit. Students compared John Smith's 1608 and 1624 accounts — the same author contradicting himself — and then examined four historians who used the same evidence to reach different conclusions. The pedagogical power of this design lies in the layered contradiction: first, the same person disagrees with his earlier self; then, professional historians disagree with each other using the same documents. Students learn that historical knowledge is not found in any single source but constructed through the comparison and weighing of multiple accounts.
93
94The Pocahontas chapter in Wineburg, Martin, and Monte-Sano (2011) operationalised corroboration through structured comparison tools. Students used worksheets that required them to identify what each source says, where sources agree and disagree, and what might explain the differences. The lesson architecture — reading sources in successive rounds, with whole-class discussion after each round — was designed to scaffold the comparative reasoning that corroboration demands.
95
96Reisman (2012) found no significant treatment effects for corroboration. Her explanation was twofold: corroboration requires connections between documents (harder to model with discrete actions than sourcing), and the instructional conditions in her study may not have supported it — whole-class discussion, where comparative reasoning becomes visible and practicable, was extremely rare in treatment classrooms. This suggests that corroboration may require more dialogic, discussion-based instruction than a document-based lesson structure typically provides.
This is a preview of SKILL.md. Download or install the skill to get the whole thing.
In the file
SKILL.md4,197 words
Files1
Licencenot declared
Why you can read it

Nothing in a skill executes. The client loads the text and the model follows it, so a skill can be audited the way a runbook is — by reading it.

What it costs in context

Skills are not billed by the call. They are paid for in context: every token the instructions occupy is a token your code, your diff and your conversation cannot use. Here is what this one takes and when it takes it.

≈1,130
always loaded
The name and description, so the model knows the skill exists and when to reach for it.
6,320
on trigger
The instruction body, read only when the skill fires.
3.7%
of a 200k window
Ten skills this size would take about 37% of the window before you open a file.
050k100k150k200k context window

7.5k tokens, estimated from the bundle at four bytes to the token, held for the rest of the session once it triggers. Heavy. Teams tend to install this one per project rather than globally, and load it only when the job comes up.

Servers bill, skills cost

A server charges by the month. A skill charges once per session, in context, and then keeps charging it for as long as the session lives.

Before and after

The same question, put to the same model twice: once as it comes, and once with these instructions loaded.

No worked example has been published for this skill yet.

The procedure it runs

The procedure has not been set out here step by step. It is in the body of its SKILL.md: the start of it is shown above, and the whole file comes with the install.

Prose, not code

These steps are written for a model to follow, not executed by a runtime. It can still be told to skip one, and it will say so when it does.

Servers it uses

None. This skill calls no MCP servers at all.

Everything it needs is in the instructions, so it works in a project with nothing connected — the model reads the file and changes how it works with what it can already reach.

Its SKILL.md does not declare which tools it asks the agent for, so what it touches is whatever the instructions themselves ask for — read them before you install it.

What it asks for
Writes filesnot declared
Network accessnot declared

This SKILL.md carries no allowed-tools line, so neither is declared. A skill grants no permissions of its own — it can only ask for tools your client already has.

What it will not do

Every skill is narrow, and the useful ones say where they stop. These are the jobs this one is the wrong tool for.

What this skill is not for has not been published here. Nothing is implied by that: it is a section the author has not filled in.

What is in the bundle

1 file, 29.8 kB on disk. A bundle is text throughout: the instructions the model reads, plus the templates it fills in.

  • SKILL.md29.8 kB
What is not in it

No dependencies and nothing executable: a skill is text the agent reads, so the bundle is 1 file you can review in full before installing.

Install

Installing copies the bundle into your project. Nothing runs at install time — the files sit on disk until the model reads them.

# Corroboration Skill Builder · 7.5k tokens when loaded · macOS, Linux mkdir -p .claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/corroboration-skill-builder/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/corroboration-skill-builder" ] && { [ ! -e .claude/skills/corroboration-skill-builder ] || { mv .claude/skills/corroboration-skill-builder "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/corroboration-skill-builder" .claude/skills/ && echo "Installed .claude/skills/corroboration-skill-builder"
On Windows, or any OS with Node 20+
npx mcprush@latest skill add garethmanning/corroboration-skill-builder

Windows PowerShell says 'running scripts is disabled on this system'? Run Set-ExecutionPolicy -Scope CurrentUser RemoteSigned once, or type npx.cmd instead of npx (codex.cmd, gemini.cmd, grok.cmd likewise). PowerShell 7 needs neither. Writes to .claude/skills/corroboration-skill-builder/ in the current project. For every project instead, run mkdir -p ~/.claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/corroboration-skill-builder/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/corroboration-skill-builder" ] && { [ ! -e ~/.claude/skills/corroboration-skill-builder ] || { mv ~/.claude/skills/corroboration-skill-builder "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/corroboration-skill-builder" ~/.claude/skills/ && echo "Installed ~/.claude/skills/corroboration-skill-builder" (macOS, Linux) — or add --global to the npx line. The curl line replaces .claude/skills/corroboration-skill-builder/ only after the download succeeds, so files left there by another skill of the same name, or by an older release, do not mix in. A copy already there is moved aside, not deleted, and the line prints where.

Which clients pick it up on their own

A skill is a folder of text. Most of these read a skills folder and pick it up without being told; the rest take the same folder another way — an upload in the app, a parameter on an API call — and then choose it by its description just the same.

Claude Code.claude/skills/
Claude DesktopCustomize › Skills
ChatGPTSkills › Create › Upload
Cursor.cursor/skills/
VS Code.github/skills/
Codex CLI.agents/skills/
Gemini CLI.gemini/skills/
Grok Build.grok/skills/
Microsoft CopilotSkills › Upload a skill
PerplexityComputer › Skills › Upload a skill
DeepSeek Harness.dsh/skills/
Zed.agents/skills/
Devin Desktop.devin/skills/
Windsurf (legacy).windsurf/skills/
OpenAI Agents SDKInstructions or sandbox Skills
HTTP / APIa request parameter
This release
Version1.0
Publishedno release date on file
PriceFree
Referencegarethmanning/corroboration-skill-builder

Versions

v1.0 is what is on the shelf; no release here carries a date. Instructions change more often than APIs do — a skill can be rewritten entirely without anything it depends on moving.

v1.0
  • No earlier releases have been published to the marketplace.
Pinning

The install command always fetches the release that is current the day you run it — v1.0 today — and cannot ask for an earlier one. The copy on your disk does not change until you run it again.

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