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.
npx agentmods add skills/matrixfounder/agentic-development/skill-update-memorynpx skills add MatrixFounder/Agentic-development --skill skill-update-memorygit clone --depth 1 https://github.com/MatrixFounder/Agentic-developmentWhat 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 | $0.00016 | $0.00560 |
| Opus 5 | $0.00008 | $0.00280 |
| Sonnet 5 | $0.00003 | $0.00112 |
| Haiku 4.5 | $0.00002 | $0.00056 |
Grade A, and why
skill-update-memory 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 2d 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.
How it starts
The opening of the file, as written. The whole thing — 75 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Update Memory Skill
Purpose
Prevent "Agent Amnesia" by keeping .AGENTS.md context files synchronized with code changes.
When to Use
- Before committing code (Developer).
- During Code Review (Reviewer).
- In
04-update-docsworkflow.
Strategy: Automated Detection + Manual Description
Phase 1: Detect Changes
Tool: scripts/suggest_updates.py
Usage:
python3 .agent/skills/skill-update-memory/scripts/suggest_updates.py
Bootstrap Migration Mode (optional):
python3 .agent/skills/skill-update-memory/scripts/suggest_updates.py --mode bootstrap --create-missing --development-root src
Output:
- Identifies modified source files (ignoring build artifacts).
- Groups them by the closest
.AGENTS.md(or suggested per-directory target in source folders). - Generates a template for the update.
- In bootstrap mode, can create missing
.AGENTS.mdfiles without overwriting existing ones. - Creation/suggestions are limited to explicit development roots (
--development-root, default:src). /.agent/skills/*and/.cursor/skills/*are always excluded from memory target creation.
[!NOTE]
.AGENTS.mdremains optional. If it does not exist, the helper must not fail.
Phase 2: Generate Description (.AGENTS.md Update)
For each file listed by the script:
- Identify Change Type:
- New File -> Create entry.
- Modified Logic -> Update description/functions.
- Deleted -> Mark as
(Deleted).
- Write Description:
- Focus on Purpose (Why does it exist?).
- List public Classes/Functions.
Phase 3: Preservation
[!IMPORTANT] NEVER delete sections marked
[Human Knowledge]or<!-- PRESERVE -->.
Append new information below manual annotations.
Example Update
### [new_service.py]
**Purpose:** Handles user authentication.
**Classes:**
- `AuthService` — Main entry point.
- `login()` — Validates credentials.
Integration
- Code Review: Reviewer runs script to check if docs match code changes.
- Pre-Commit: Developer runs script to ensure no "Undocumented Code" is committed.
- Migration/Onboarding: Run bootstrap mode for external projects to create initial
.AGENTS.mdskeletons in source folders.
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.
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.
- 2d ago First seen · 75 lines · 16 tokens per session scan A 160ae0e4c490
skill-update-memory is a skill published in the GitHub repository MatrixFounder/Agentic-development (5 stars, last pushed 19d ago), licensed Apache-2.0. It adds 16 tokens to every session and 560 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.
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