keystone: Agent for Claude Code

.claude/agents/keystone-mode-switcher.md

keystone-mode-switcher is an agent for Claude Code from tacoda/keystone. It costs 23 tokens per session (183 once invoked), scanned A, a copy of mode-switcher, MIT.

A workflow setting that controls whether an agent works with a partner, alone, or with automated steps. It reads and updates the project's pacing mode.

In plain words
What is it for?
Use it to switch between paired, solo, and autopilot work in a project that uses a charter file to define its process.
Why use it?
It prevents invalid workflow changes and makes clear which approval checks become looser or stricter when the mode changes.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter.

This is tacoda/keystone's own configuration. It tells Claude Code how to work on keystone itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything keystone configures →

Reuse

Borrowing it

Nothing to install: this file belongs to tacoda/keystone. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/tacoda/keystone/main/.claude/agents/keystone-mode-switcher.md
Clone the repo
git clone --depth 1 https://github.com/tacoda/keystone

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 keystone-mode-switcher

README.md
[![agentmods](https://agentmods.dev/badge/agents/tacoda/keystone/keystone-mode-switcher/github.svg)](https://agentmods.dev/agents/tacoda/keystone/keystone-mode-switcher)
Your own site
<a href="https://agentmods.dev/agents/tacoda/keystone/keystone-mode-switcher"><img src="https://agentmods.dev/badge/agents/tacoda/keystone/keystone-mode-switcher/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 keystone-mode-switcher

Your own site · 80×15
<a href="https://agentmods.dev/agents/tacoda/keystone/keystone-mode-switcher"><img src="https://agentmods.dev/badge/agents/tacoda/keystone/keystone-mode-switcher.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 23 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 183 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 88% copy Near-identical to another mod 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 $0.00023 $0.00183
Opus 5.5 $0.00009 $0.00073
Sonnet 5.5 $0.00005 $0.00037
Haiku 4.5 $0.00002 $0.00018

Measured 2mo ago against content hash bc92c29ba236, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

keystone-mode-switcher 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 2mo 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.

Origin

This is a copy

88% identical to mode-switcher — 5 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.claude/agents/keystone-mode-switcher.md · 36 lines

What it actually says

Mode switcher

You change the charter pacing mode. Read the current mode from .charter/corpus/state/mode.md, validate the requested target, and write the new mode file.

Posture

  • Refuse silently invalid transitions; explain why.
  • Surface the implications of the target mode (what gates relax, what gates tighten).
  • Confirm before writing — pacing mode change is irreversible without another switch.

Output

---
from: <current>
to:   <target>
gates_relaxed: [...]
gates_tightened: [...]
---

Followed by a one-paragraph note on what changes for the user.

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. 2mo ago First seen · 36 lines · 23 tokens per session scan A bc92c29ba236

Subscribe to this mod's changes

keystone-mode-switcher is an agent published in the GitHub repository tacoda/keystone (44 stars, last pushed 3mo ago), licensed MIT. It adds 23 tokens to every session and 183 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 88% identical to mode-switcher, differing in 5 lines, and is treated as a copy.

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