What is skill-history?

A command that lists the skills used during the current Claude Code session. It reads filtered session information through a provided script rather than displaying the entire session file.

Use it to review invoked skills, their timestamps, and nearby session context.

It helps you find out which skills were activated and what may have triggered them, without manually searching a large session log.

skill-history — Command for Claude Code by dwmkerr

Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code

/plugin marketplace add dwmkerr/claude-toolkit

Claude Code

/plugin install toolkit

Made for: Claude Code.

Or install toolkit, the plugin that ships this one along with the rest of its 15 skills, 3 commands, 1 agent.

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.

README.md

[![agentmods](https://agentmods.dev/badge/commands/dwmkerr/claude-toolkit/skill-history/github.svg)](https://agentmods.dev/commands/dwmkerr/claude-toolkit/skill-history)

Your own site

<a href="https://agentmods.dev/commands/dwmkerr/claude-toolkit/skill-history"><img src="https://agentmods.dev/badge/commands/dwmkerr/claude-toolkit/skill-history/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.

Your own site · 80×15

<a href="https://agentmods.dev/commands/dwmkerr/claude-toolkit/skill-history"><img src="https://agentmods.dev/badge/commands/dwmkerr/claude-toolkit/skill-history.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 8 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 603 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.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00008	$0.00603
Opus 5	$0.00004	$0.00302
Sonnet 5	$0.00002	$0.00121
Haiku 4.5	$0.00001	$0.00060

Measured 9d ago against content hash 274ee2fb4129, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

skill-history 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 9d 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.

plugins/toolkit/commands/skill-history.md · 91 lines

How it starts

The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill History

Show which skills were invoked during the current Claude Code session.

CRITICAL: Do NOT read the session file directly - it's too large. Use the Bash tool to run grepsession.sh which filters efficiently.

Instructions

Use Bash to run grepsession.sh
```
${CLAUDE_PLUGIN_ROOT}/scripts/grepsession.sh '"name":"Skill"'
```
This outputs matching lines with line numbers from the current session.

Parse the output

Each line is JSONL with this structure:

{
  "type": "assistant",
  "timestamp": "2025-01-05T09:23:15.123Z",
  "message": {
    "content": [
      {
        "type": "tool_use",
        "name": "Skill",
        "input": {
          "skill": "typescript-development",
          "args": ""
        }
      }
    ]
  }
}

Extract:

Line number: from grep prefix (e.g., 1247:{...})
Time: from .timestamp
Skill: from .message.content[].input.skill

If you need more context
```
${CLAUDE_PLUGIN_ROOT}/scripts/grepsession.sh '"name":"Skill"' -C 5
```
Or use Read tool with offset/limit on the session file.

To find what triggered each skill

Look for the most recent user message before each skill. User messages have this structure:

{
  "type": "user",
  "timestamp": "2025-01-05T09:23:00.000Z",
  "message": {
    "content": "fix the type errors in the project"
  }
}

Display results

Format timestamps as relative time (e.g., "3m ago", "1h ago", "2d ago").

## Skills Invoked This Session

| Line | When     | Skill              | Triggered By                    |
|------|----------|--------------------|--------------------------------|
| 1247 | 2h ago   | typescript-dev     | "fix the type errors in..."    |
| 1389 | 45m ago  | technical-writing  | "improve the readme..."        |

**Total**: 2 skills invoked

Read the full file on GitHub · 91 lines

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.

9d ago First seen · 91 lines · 8 tokens per session scan A 274ee2fb4129

Subscribe to this mod's changes

skill-history is a command published in the GitHub repository dwmkerr/claude-toolkit (23 stars, last pushed 2d ago), licensed MIT. It adds 8 tokens to every session and 603 once invoked, about $0.0000 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.

Building agents

skill-history

Getting it into your agent

Wrote this? Show the measurements

What it costs to keep this loaded

Grade A, and why

Nothing flagged

How it starts

Skill History

Instructions

What this file has done since we first saw it

Other commands, from other repositories

checklist

clarify

specify

converge

implement

analyze