Source Validation

Source Validation is a skill for Claude Code, Codex from notforyou23/home23. It costs 24 tokens per session (362 once invoked), scanned A, original, MIT.

A process for checking whether claims and their sources are trustworthy, current, traceable, and potentially biased. It favors original sources over summaries when possible.

In plain words
What is it for?
Use it to verify claims, identify the best supporting source, check authorship and dates, compare disagreements, and report confidence and possible bias.
Why use it?
It reduces the risk of treating popular, outdated, derivative, or circularly cited information as fact.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/notforyou23/home23/source-validation
Any agent
npx skills add notforyou23/home23 --skill source-validation
Clone the repo
git clone --depth 1 https://github.com/notforyou23/home23

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.

agentmods badge for Source Validation

README.md
[![agentmods](https://agentmods.dev/badge/skills/notforyou23/home23/source-validation.svg)](https://agentmods.dev/skills/notforyou23/home23/source-validation)
Your own site
<a href="https://agentmods.dev/skills/notforyou23/home23/source-validation"><img src="https://agentmods.dev/badge/skills/notforyou23/home23/source-validation.svg" alt="Measured on agentmods" height="20"></a>
Per session 24 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 362 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00024 $0.00362
Opus 5 $0.00012 $0.00181
Sonnet 5 $0.00005 $0.00072
Haiku 4.5 $0.00002 $0.00036

Measured 4d ago against content hash d430e71cf107, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

Source Validation 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 4d 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.

workspace/skills/source-validation/SKILL.md · 68 lines

What it actually says

Source Validation

Use this skill before you promote a claim to fact.

When to use

Use source-validation for:

  • checking whether a source is primary or derivative
  • validating recency-sensitive claims
  • spotting bias, missing provenance, or circular citation
  • comparing multiple sources on the same claim

Workflow

  1. Identify the claim being validated.
  2. Find the closest primary source available.
  3. Check date, authorship, and provenance.
  4. Look for disagreement or unsupported jumps in secondary summaries.
  5. Rate confidence and explain why.

Output

  • Claim
  • Best supporting source
  • Source type: primary, secondary, tertiary
  • Risks or bias
  • Confidence

Gotchas

  • Popularity is not evidence.
  • A recent article can still be derivative and weak.
  • If the claim is unsettled, report the uncertainty instead of forcing a verdict.

Examples

Validate this claim before we cite it:
"Company X signed the deal on April 12."
Prefer the primary filing or official announcement over commentary.
Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 4d ago First seen · 68 lines · 24 tokens per session scan A d430e71cf107

Subscribe to this mod's changes

Source Validation is a skill published in the GitHub repository notforyou23/home23 (11 stars, last pushed today), licensed MIT. It adds 24 tokens to every session and 362 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 2026-08-30.

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