Borrowing it
Nothing to install: this file belongs to jarmstrong158/context-keeper. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/jarmstrong158/context-keeper/main/CLAUDE.mdgit clone --depth 1 https://github.com/jarmstrong158/context-keeperWrote 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/instructions/jarmstrong158/context-keeper/claude-md)<a href="https://agentmods.dev/instructions/jarmstrong158/context-keeper/claude-md"><img src="https://agentmods.dev/badge/instructions/jarmstrong158/context-keeper/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.
<a href="https://agentmods.dev/instructions/jarmstrong158/context-keeper/claude-md"><img src="https://agentmods.dev/badge/instructions/jarmstrong158/context-keeper/claude-md.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 | $0.04969 | $0.04969 |
| Opus 5.5 | $0.01988 | $0.01988 |
| Sonnet 5.5 | $0.00994 | $0.00994 |
| Haiku 4.5 | $0.00497 | $0.00497 |
Grade A, and why
context-keeper CLAUDE.md scanned grade A with 1 finding 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
**Surfaces 1 and 3 are on the critical path — treat their cost as a budget.** A PreToolUse hook runs before the tool does, so every millisecond it spends delays every Edit and Write in every project. `hooks/scope_guard.p How it starts
The opening of the file, as written. The whole thing — 219 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Context Keeper MCP Server
Context Keeper maintains project memory across Claude conversations: architectural decisions, pipeline flows, and constraints that must not be forgotten or violated.
Project Resolution
Context Keeper stores data in a .context/ directory inside a project. The server resolves the project directory in this order:
CONTEXT_KEEPER_PROJECTenv var (explicit opt-in — trusted)- The Xylem session pointer
~/.xylem/active_project.json(override withXYLEM_ACTIVE_PROJECT_FILE), written by the Xylem SessionStart hook. Also an explicit opt-in: it exists so a persistent server follows the session's project rather than the directory it happened to be launched from, so it outranks cwd discovery. - cwd, but only if it already contains a
.context/directory - Walk parent dirs from cwd, returning the first ancestor that already contains a
.context/(git-style discovery — so launching from a subdirectory of your project still resolves correctly) - Otherwise: refuse.
record_*,update_entry,deprecate_entry, andprune_staleall return an "unresolved project" error.
Steps 3 and 4 only resolve to directories that already contain .context/. The server never creates one implicitly, so you will never silently create a stray .context/ in the wrong directory. The footgun from earlier versions — where Claude Code was launched from a parent directory and polluted it — is fixed at the code level.
All 14 tools accept project_dir for explicit cross-project targeting. When cwd doesn't resolve, pass project_dir to any tool — including record_*.
Still good practice:
- When recording to a non-obvious project, confirm with the user which project you're targeting before calling
record_*.
Capture Loop
Context Keeper has two halves:
- Retrieval (session start): The SessionStart hook injects the compaction report and project summary directly into context (it runs the handlers itself and prints their output). Retrieval is automatic and unskippable — you do not need to call the tools to be oriented on what's already recorded.
get_compaction_report/get_project_summaryremain callable on demand.
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.
- 2mo ago First seen · 219 lines · 4,969 tokens per session scan A 74b6ac4109c8
context-keeper CLAUDE.md is an instructions file published in the GitHub repository jarmstrong158/context-keeper (1 stars, last pushed 2mo ago), licensed MIT. It adds 4,969 tokens to every session, about $0.0199 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
context-keeper CLAUDE.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| context-keeper CLAUDE.mdjarmstrong158/context-keeper | Instructions file | 1 | 2mo ago | MIT | A | 4,969 | Claude Code |
| vscode buildNext.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 9,719 | GitHub Copilot |
| next.js AGENTS.mdvercel/next.js | Instructions file | 143k | yesterday | MIT | A | 7,461 | Codex, OpenCode |
| langchain AGENTS.mdlangchain-ai/langchain | Instructions file | 149k | yesterday | MIT | A | 4,680 | Codex, OpenCode |
| vscode oss-third-party-notices.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 5,516 | GitHub Copilot |
| vscode copilot-instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 3,093 | GitHub Copilot |
| deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness | Instructions file | 274k | 2d ago | MIT | A | 4,313 | Codex, OpenCode |