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.
git clone --depth 1 https://github.com/nyxCore-Systems/letter-for-myselfWrote 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.
[](https://agentmods.dev/agents/nyxcore-systems/letter-for-myself/letter-to-myself)<a href="https://agentmods.dev/agents/nyxcore-systems/letter-for-myself/letter-to-myself"><img src="https://agentmods.dev/badge/agents/nyxcore-systems/letter-for-myself/letter-to-myself/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.
<a href="https://agentmods.dev/agents/nyxcore-systems/letter-for-myself/letter-to-myself"><img src="https://agentmods.dev/badge/agents/nyxcore-systems/letter-for-myself/letter-to-myself.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00017 | $0.00311 |
| Opus 5 | $0.00009 | $0.00156 |
| Sonnet 5 | $0.00003 | $0.00062 |
| Haiku 4.5 | $0.00002 | $0.00031 |
Grade A, and why
letter-to-myself 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 11d 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.
What it actually says
Identity
You are the Context Persistence Agent. Your goal is to prevent "amnesia" between coding sessions.
The Protocol
You act as a normal coding assistant, BUT you have a special directive.
THE TRIGGER:
When the user types /checkpoint, exit, or indicates the session is over, you MUST:
- Stop all coding tasks.
- Review the conversation history.
- Generate a Markdown summary (The Letter).
- Execute the
letter-checkpointskill.
The Letter Template
# 📨 Letter to Myself (Session Handoff)
## 1. Executive Summary
* **Goal:** ...
* **Current Status:** ...
## 2. The "Done" List
* Implemented [Feature A].
## 3. The "Pain" Log (CRITICAL)
* **Tried:** [Library/Method]
* **Failed:** [Error message]
* **Solution:** [How we fixed it]
## 4. Variable State
* Ports, env vars, mocked data.
## 5. Next Steps
1. [ ] ...
Startup Behavior
Check the file list immediately. If a .memory/ folder exists, READ the alphanumerically last file to restore context.
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.
- 11d ago First seen · 47 lines · 17 tokens per session scan A b6e88a691013
letter-to-myself is an agent published in the GitHub repository nyxCore-Systems/letter-for-myself (4 stars, last pushed 1mo ago), licensed MIT. It adds 17 tokens to every session and 311 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 2026-08-31.
Other agents, from other repositories
context-finder
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wiki-ingest
Use this agent when ingesting URLs, files, or pasted text into the vault during automated maintenance cycles. Typical triggers include dev-loop IDLE DISCOVERY ingestion, batch source processing, or converting raw captures to typed-knowledge pages. See "When to invoke" in the agent body for worked scenarios.
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.NET-Notebook-Migration-Agent
Expert .NET and documentation transformation agent that migrates Polyglot Jupyter notebooks into clean Markdown and companion .NET sample code.
AVM Owner Triage
Triage open GitHub issues across the Azure Verified Modules (AVM) repos an owner maintains. Splits the backlog into a Copilot-delegatable pile and a human pile, produces a report with a delegation ratio, and never comments or assigns without explicit user approval.