update-claude-md

update-claude-md is a skill for Claude Code from rajitsaha/100xprism. It costs 75 tokens per session (411 once invoked), scanned A, original, MIT.

A guide that records corrections as lasting rules in a project's CLAUDE.md instruction file.

In plain words
What is it for?
Use it after correcting an agent's behavior to document the expected rule for future work.
Why use it?
It helps prevent the same mistake from happening again in later coding sessions.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: model in frontmatter; mentions CLAUDE.md; installed under .agents/ (shared by several agents).

Good fit Use it after correcting an agent's behavior to document the expected rule for future work.

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Install with agentmods
npx agentmods add skills/rajitsaha/100xprism/update-claude-md
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.

Any agent
npx skills add rajitsaha/100xprism --skill update-claude-md
Clone the repo
git clone --depth 1 https://github.com/rajitsaha/100xprism

Made for: Claude Code.

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 update-claude-md

README.md
[![agentmods](https://agentmods.dev/badge/skills/rajitsaha/100xprism/update-claude-md/github.svg)](https://agentmods.dev/skills/rajitsaha/100xprism/update-claude-md)
Your own site
<a href="https://agentmods.dev/skills/rajitsaha/100xprism/update-claude-md"><img src="https://agentmods.dev/badge/skills/rajitsaha/100xprism/update-claude-md/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 update-claude-md

Your own site · 80×15
<a href="https://agentmods.dev/skills/rajitsaha/100xprism/update-claude-md"><img src="https://agentmods.dev/badge/skills/rajitsaha/100xprism/update-claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 75 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 411 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Excessive Agency · line 8
    Skill selects an external model or provider that may use a different account or billing plan than the operator expects. Undisclosed model switches can cause unexpected cost or quota consumption.
    Fix: Remove the model/provider override or disclose it prominently and require explicit operator approval before invoking an external coding CLI or billed model.
How audits are shown
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 $0.00075 $0.00411
Opus 5 $0.00037 $0.00205
Sonnet 5 $0.00015 $0.00082
Haiku 4.5 $0.00007 $0.00041

Measured 6d ago against content hash 81e5e6958a93, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

update-claude-md 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 6d 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/skills/update-claude-md/SKILL.md · 53 lines

What it actually says

Update-Claude — CLAUDE.md Rule Writer

After any correction, update CLAUDE.md with a rule to prevent the same mistake recurring.

How to use

  • /update-claude — after a correction, write a rule to CLAUDE.md

Phase 1 — Identify the pattern

What went wrong? What should have been done instead? Be specific — one clear pattern, not a vague note.


Phase 2 — Write a rule

Formulate as a clear, actionable rule:

- [Rule]: [What to do / not to do]. Why: [brief context].

Short rules stick. Long paragraphs get ignored.


Phase 3 — Update CLAUDE.md

PROJECT_ROOT=$(git rev-parse --show-toplevel)
INSTRUCTION_FILE=$(for f in CLAUDE.md AGENTS.md .cursorrules; do [ -f "$PROJECT_ROOT/$f" ] && echo "$PROJECT_ROOT/$f" && break; done)

Append the rule under a ## Rules or ## Corrections section in the project's instruction file. If no instruction file exists, create CLAUDE.md in the project root.


Phase 4 — Confirm

Tell the user: "Updated [file] with: [rule summary]"

If the rule isn't reducing mistakes after 2–3 sessions: rewrite it — be more specific or more prominent.

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. 6d ago First seen · 53 lines · 75 tokens per session scan A 81e5e6958a93

Subscribe to this mod's changes

update-claude-md is a skill published in the GitHub repository rajitsaha/100xprism (10 stars, last pushed 10d ago), licensed MIT. It adds 75 tokens to every session and 411 once invoked, about $0.0004 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 2026-09-03.