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 skills add eai-org/agent-toolkit --skill context-checkupgit clone --depth 1 https://github.com/eai-org/agent-toolkitWrote 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/skills/eai-org/agent-toolkit/context-checkup)<a href="https://agentmods.dev/skills/eai-org/agent-toolkit/context-checkup"><img src="https://agentmods.dev/badge/skills/eai-org/agent-toolkit/context-checkup/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/skills/eai-org/agent-toolkit/context-checkup"><img src="https://agentmods.dev/badge/skills/eai-org/agent-toolkit/context-checkup.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 4 findings, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Agent Snooping · line 50 Skill reads from agent configuration directories (.claude/, .codex/, .gemini/). These directories may contain API keys, personal settings, and other credentials that the skill has no legitimate need to access.Fix: Remove all code or instructions that access agent configuration directories (.claude/, .codex/, .gemini/). If configuration values are needed, pass them explicitly as parameters or environment variabl
- high Agent Snooping · line 70 Skill reads from agent configuration directories (.claude/, .codex/, .gemini/). These directories may contain API keys, personal settings, and other credentials that the skill has no legitimate need to access.Fix: Remove all code or instructions that access agent configuration directories (.claude/, .codex/, .gemini/). If configuration values are needed, pass them explicitly as parameters or environment variabl
- high Agent Snooping · line 70 Skill reads from agent configuration directories (.claude/, .codex/, .gemini/). These directories may contain API keys, personal settings, and other credentials that the skill has no legitimate need to access.Fix: Remove all code or instructions that access agent configuration directories (.claude/, .codex/, .gemini/). If configuration values are needed, pass them explicitly as parameters or environment variabl
- high Agent Snooping · line 70 Skill accesses MCP server configuration files (mcp.json). MCP configs contain server URLs, authentication tokens, and tool definitions — reading them allows the skill to discover and potentially abuse other tool integrations.Fix: Remove all code or instructions that read MCP configuration files (mcp.json). MCP server details should be managed by the agent runtime, not read by individual skills.
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 | $0.00027 | $0.02052 |
| Opus 5.5 | $0.00011 | $0.00821 |
| Sonnet 5.5 | $0.00005 | $0.00410 |
| Haiku 4.5 | $0.00003 | $0.00205 |
Grade A, and why
context-checkup scanned grade A with 2 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Reads agent configuration directorieslowAgent snooping
.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.
find -L "$p/.claude/rules" "$c/rules" -name '*.md' -exec sh -c 'for f; do awk '"'"'NR==1&&$0!="---"{exit 1} NR>1&&$0=="---"{exit 1} NR>1&&/^paths:/{f=1;exit} END{exit !f}'"'"' "$f" || printf "%s\0" "$f"; done' _ {} + 2>/ Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
Reads MCP configurationlowAgent snooping
mcp.json carries server URLs and auth tokens; reading it lets a mod discover and abuse other integrations.
{ [ -f "$s/.mcp.json" ] && cat "$s/.mcp.json"; } || echo "no .mcp.json at $s"; cat "$p/.claude/settings.json" "$r/.claude/settings.local.json" 2>/dev/null; [ "$s" = "$r" ] || cat "$s/.claude/settings.local.json" 2>/dev/n Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
How it starts
The opening of the file, as written. The whole thing — 109 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Context checkup
Find what loads automatically into the session's context at startup, quantify it, and propose reversible trims ranked by payoff — shrink the startup context window by cutting what isn't worth its tokens. Read-only — measure and recommend; change settings only on explicit approval.
Mental model (spend attention top-down)
Cost hierarchy, biggest first:
- MCP tool schemas — large, but deferred by tool search. Only a problem if tool search is OFF.
- Always-on text — every always-on instruction file (entry-file chain,
@imports, unscoped rules files) and skill/agent/command descriptions: every available one's description loads every session, except skills flagged non-model-invocable (their description never loads; a manual-only skill costs nothing until invoked). - MCP server instructions — load per enabled server at startup; a chatty preamble can dwarf its tool names.
- MCP tool names — ~10 tokens each. Cheap; 30 names ≈ 300 tokens isn't worth a recommendation.
Rules: measure, never guess — wc/count each source, convert with tokens ≈ words × 1.3 for
prose and characters / 4 otherwise, and state that rule once in the table header. When the agent
has a built-in context breakdown command, ask the user to paste its output and use its numbers as
the baseline; estimate only what it does not break down. Rank by tokens-saved × reversibility.
Distinguish auto-loaded from lazy-linked (nested AGENTS.md referenced from a parent are
not loaded — don't flag them).
Tool-name counts, the skills/agents/commands lists, and tool-search status come from the session's system-reminders, not disk — read them from your own context.
Checklist
Mechanics below are one agent's (settings keys, ~/.claude paths, which CLAUDE_CONFIG_DIR
relocates); on another agent, map each item to its equivalent or ask. p, s and r are the
anchors defined under Useful probes.
0. Verify tool search is on first. Evidence is the session itself: MCP tools listed as deferred
(names only, searched on demand) means on, even once a search has pulled some schemas in; full
schemas loaded from the start means off, and every "names are cheap" conclusion flips. Only then
read the env var or setting (ENABLE_TOOL_SEARCH, incl. auto:N threshold modes) to explain why.
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.
- 5d ago Changed · +7 lines 257f3f061b45
- 6d ago Changed · +30 lines cbdacb9c3dcd
- 1mo ago First seen · 72 lines · 27 tokens per session scan A 3c8aa73af787
context-checkup is a skill published in the GitHub repository eai-org/agent-toolkit (75 stars, last pushed yesterday), licensed MIT. It adds 27 tokens to every session and 2,052 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 2 findings (reads agent configuration directories, reads mcp configuration). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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Self-learning system that captures corrections during sessions and reminds users to run /reflect to update CLAUDE.md. Use when discussing learnings, corrections, or when the user mentions remembering something for future sessions.