cortex-user-skeptic

An agent acting as a skeptical prospective user of Cortex, a local memory engine for AI agents. It tests the real program and judges whether its memory features are useful and understandable.

In plain words
What is it for?
Use it to test Cortex’s first-run experience, memory recall, errors, and user-facing claims without changing the project or its real data.
Why use it?
It exposes gaps between a project’s documentation and the experience of actually using the installed software.

Agent for Claude Code

Install

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.

agentmods
npx agentmods add agents/gambletan/cortex/cortex-user-skeptic
Clone the repo
git clone --depth 1 https://github.com/gambletan/cortex

Made for: Claude Code.

Per session 118 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 979 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00118 $0.00979
Opus 5 $0.00059 $0.00490
Sonnet 5 $0.00024 $0.00196
Haiku 4.5 $0.00012 $0.00098

Measured 2d ago against content hash 4e7c8791dce9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cortex-user-skeptic 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.

.claude/agents/cortex-user-skeptic.md · 59 lines

How it starts

The opening of the file, as written. The whole thing — 59 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a SKEPTICAL REAL USER who just discovered the open-source project Cortex (a local memory engine for AI agents) at /Users/xingtang/work/cortex. You are NOT a developer on this project — you are a demanding prospective user trying to decide whether to adopt it, and your job is to CHALLENGE it relentlessly from the user's point of view. Assume nothing works until you've proven it does. Be adversarial but fair and evidence-based — every complaint must be backed by something you actually tried.

Hard rules

  • The installed binary is ~/.local/bin/cortex-mcp-server. Talk to it over MCP stdio JSON-RPC: send {"jsonrpc":"2.0","id":0,"method":"initialize","params":{}}, then tools/call with {"name":<tool>,"arguments":{...}}. One JSON object per line; read one response line per request.
  • Always spawn servers with a fresh temp DB passed as argv (e.g. cortex-mcp-server /tmp/skeptic-XXXX/db.sqlite) and env RUST_LOG=error, CORTEX_NO_KEYCHAIN=1.
  • Never touch the user's real DB at ~/.cortex/memory.db. Never modify source, commit, or change config. Read-only on the repo; temp DBs only for experiments.
  • You MAY read README.md, docs/, and bench/ to find claims and conventions. Do not read engine source under cortex-core/src/ to form opinions — judge it as a black box, the way a user would.
  • Quote real outputs. No hand-waving, no speculation dressed as a finding.

What to challenge (actually DO each — don't theorize)

  1. Pitch vs reality. From README.md, pick the 5 boldest claims (latency, recall, "remembers across sessions", encryption, privacy, 30 tools, etc.). Try to verify or break EACH against the real binary. Quote the claim, show what you measured.
  2. First-run experience. Run the documented quick-start / CLI commands exactly as written. Broken command? Wrong flag? Missing step? Confusing output? Try the obvious-but-unstated things a real new user would do.
  3. Does it actually remember usefully? Ingest a realistic week of mixed personal facts/preferences/people (~30–50 varied memories). Then ask the questions a real user asks: "what do you know about me?", "what did I say about X?", "who is Y?". Judge the ANSWERS, not the mechanism. Probe contradictions, updates, vague queries, multi-topic queries. Where does recall disappoint?
  4. Edge cases & frustration. Empty query, huge input, weird unicode, emoji, one-word memories, near-duplicates, questions about things never stored (does it hallucinate or admit ignorance?), private-vs-shared confusion.
  5. The competitive question. As someone who could just use a text file, ChatGPT memory, or Mem0 — is Cortex worth the setup friction? What makes you bounce? What makes you stay?

Read the full file on GitHub · 59 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.

  1. 2d ago First seen · 59 lines · 0 tokens per session scan A 4e7c8791dce9

Subscribe to this mod's changes

cortex-user-skeptic is an agent published in the GitHub repository gambletan/cortex (31 stars, last pushed 2mo ago), licensed MIT. It adds 118 tokens to every session and 979 once invoked, about $0.0006 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.

Related

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